A

taw(adssvscopy

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1

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(A

0d

Available online at wwwsciencedirectcom

Molecular Immunology 45 (2008) 945ndash953

The 2prime-5prime-oligoadenylate synthetase in the lowest metazoaisolation cloning expression and functional activity

in the sponge Lubomirskia baicalensis

Heinz C Schroder a Filipe Natalio a Matthias Wiens a Muhammad Nawaz Tahir bMohammed Ibrahim Shukoor b Wolfgang Tremel b Sergey I Belikov c

Anatoli Krasko a Werner EG Muller alowasta Institut fur Physiologische Chemie Abteilung Angewandte Molekularbiologie Universitat Duesbergweg 6 D-55099 Mainz Germany

b Institut fur Anorganische Chemie und Analytische Chemie der Johannes Gutenberg-Universitat Duesbergweg 10-14 D-55099 Mainz Germanyc Limnological Institute of the Siberian Branch of Russian Academy of Sciences Ulan-Batorskaya 3 RUS-664033 Irkutsk Russia

Received 31 May 2007 received in revised form 28 July 2007 accepted 31 July 2007Available online 12 September 2007

bstract

Aquatic animals especially filter feeders such as sponges [phylum Porifera] are exposed to a higher viral load than terrestrial species Until nowhe antiviral defense system in the evolutionary oldest multicellular organisms sponges is not understood One powerful protection of vertebratesgainst virus infection is mediated by the interferon (IFN)-inducible 2prime-5prime-oligoadenylate synthetase [(2-5)A synthetase] system In the present studye cloned from the freshwater sponge Lubomirskia baicalensis a cDNA encoding a 314 aa long ORF with a calculated size of 35748 Da a putative

2-5)A synthetase and raised antibodies against the recombinant protein The native enzyme was identified in a crude extract from L baicalensis bypplication of a novel separation procedure based on polymer coated ferromagnetic nanoparticles The particles were derivatized with a syntheticouble-stranded RNA [dsRNA] synthetic poly(IC) a known allosteric activator of the latent (2-5)A synthetase These particles were used to

eparate a single 35 kDa protein from a crude extract of L baicalensis which cross-reacted with antibodies raised against the sponge enzyme Initu hybridization studies revealed that highest expression of the gene is seen in cells surrounding the aquiferous canals Finally primmorphs an initro cell culture system from L baicalensis were exposed to poly(IC) they responded to this dsRNA with an increased expression of the (2-5)Aynthetase gene already after a 1-day incubation period We conclude that sponges contain the (2-5)A synthetase antiviral protection system

2007 Elsevier Ltd All rights reserved

anopa

s2fcsM

eywords Sponges Lubomirskia baicalensis Immunity (2-5)A synthetase N

Introduction

During the evolution from the uni- to the multicellular ani-als structural and functional novelties were invented and

cquired Among them are the cellndashcell and cellndashmatrix adhe-ion molecules which provide the structural elements for a

uned interaction and labor division between different cellypes Sponges as the evolutionary oldest metazoans alreadyossess the complex repertoire of characteristic animal adhe-

The following sequence from Lubomirskia baicalensis has been depositedEMBLGenBank) the cDNA the (2-5)A synthetase [LB2-5OAS] underM747627lowast Corresponding author Tel +49 6131 392 5910 fax +49 6131 392 5243

E-mail address wmuelleruni-mainzde (WEG Muller)

dndash(ttTtci

161-5890$ ndash see front matter copy 2007 Elsevier Ltd All rights reservedoi101016jmolimm200707036

rticles Toll receptor pathway

ion molecules (reviewed in Muller 1997 Muller et al004) In parallel with the acquisition of the genetic toolkitsor cell interaction and differentiation from totipotent stemells to pluripotent somatic cells (Muller 2003 Muller 2006)ponges had to develop a potent immune system (reviewed in

uller et al 1999a Muller and Muller 2003) An effectiveefenseprotection system is essential for their survival sinceas filter feeders ndash they are exposed to heavy loads of bacteria

Thakur et al 2005) and viruses (Bergh et al 1989) Sponges fil-er huge amounts of water [one ton per day and kg body weight]hrough their elaborate aquiferous system (see Simpson 1984)

hey suck water in through their inhalant openings ostia which

hen passes into the lacunae and canals to reach the choanocytehambers and subsequently leaves through the exhalant open-ngs (Simpson 1984) During this passage almost all bacterial

9 ar Im

(r

ftcMaPtstdIersua(ttelislbav

tl2mfhp2e11sdcee

ttam1shst

dab1stha(atbddpw

2

2

gPasMldquo

2

Hu

2etnaa6foadp

2

iE

46 HC Schroder et al Molecul

Wehrl et al 2007) or viral particles (to be published) areemoved from the water

Most of the molecular and functional studies with proteinsrom sponges in general and with immune molecules in par-icular have been performed with the demosponges Geodiaydonium and Suberites domuncula (reviewed in Muller anduller 2003) While a few molecules involved in selfndashself

nd selfndashnonself recognition are shared between sponges androtostomia eg tachylectin (Schroder et al 2003) most of

he immune-related molecules identified in sponges show highequence and functional similarities with sequences of Deuteros-omia such as (i) receptors displaying immunoglobulin (Ig)omains with surprisingly high sequence similarity to the humang variable region (Blumbach et al 1999) (ii) cytokines (Mullert al 1999a) and also (iii) interferon (IFN)-inducible antivi-al proteins eg the 2prime-5prime-oligoadenylate synthetase [(2-5)Aynthetase] (Muller and Schroder 1994) The IFNs have ndashntil now ndash only been found in vertebrates where they displayntiviral cell growth regulatory and immunomodulatory activityreviewed in Sen and Lengyel 1992 Stark et al 1998) Amonghe approximately 120 genes whose expression levels are underhe control of IFN in mammals (Der et al 1998) are the genesncoding the (2-5)A synthetases They comprise a family ofatent enzymes which can bind double-stranded RNA [dsRNA]n order to become active enzymatic complexes These enzymesynthesize 2prime-5prime-oligoadenylates [2-5A] that bind to a likewiseatent endonuclease [the RNase L] After activation of RNase Ly 2-5A this enzyme degrades cellular and viral RNA (Dongnd Silverman 1995) thus switching off protein biosynthesis inirus-infected cells

The group of Kelve (Kuusksalu et al 1995 1998) succeededo demonstrate that the demosponge G cydonium possesses highevels of (2-5)A synthetase and produces larger amounts of-5A surprisingly the level of synthesis is higher than in mam-alian cells Cloning the enzyme from G cydonium and later

rom S domuncula (Wiens et al 1999 Grebenjuk et al 2002)ighlighted the putative characteristic domains in the deducedrotein eg (i) the (2-5)A synthetase signature-1 and signature-(Hartmann et al 1998) (ii) the ATP-binding site which is

ssential for enzyme activity (Ghosh et al 1991 Suhadolnik994) and (iii) the putative dsRNA binding region (Ghosh et al991) Experiments furthermore revealed that the sponge (2-5)Aynthetase is inducedactivated in cells that had been exposedirectly to bacteria or to the bacterial endotoxin lipopolysac-haride (LPS Grebenjuk et al 2002) Until now however thenzyme could neither be purified nor could the enzyme in thenriched extract of G cydonium be stimulated by dsRNA

Therefore it was the aim of the present study to purifyhe enzyme and to clarify whether the sponge (2-5)A syn-hetase is also inducible by dsRNA The synthetic polyinosiniccidndashpolycytidylic acid [poly(IC)] able to bind to the mam-alian enzymes was applied as a model polymer (Hovanessian

991) and its binding property was used to isolate the (2-5)A

ynthetase from sponge crude extract For the studies describedere we selected the freshwater sponge Lubomirskia baicalen-is Freshwater sponges are evolutionary much younger thanheir 700 million old marine ancestors (Muller et al 2006b) and

vGnp

munology 45 (2008) 945ndash953

iverged from them only about 200 million years ago (Manconind Pronzato 2000) They live in waters that are less loaded withacteria and viruses than the marine environment (Pile et al997) therefore the (2-5)A synthetase was expected to be moreensitive towards microbial load than in marine sponges Forhe bindingextraction studies we used dsRNA poly(IC) whichad been immobilized onto -Fe2O3 nanoparticles (Shukoor etl 2007) After successful identification and purification of the2-5)A synthetase from L baicalensis we cloned the enzymend raised antibodies against the recombinant protein to verifyhe enzyme Furthermore we determined the expression levely in situ hybridization Finally primmorphs special three-imensional sponge cell aggregates containing proliferating andifferentiating cells (Muller et al 1999b) were treated witholy(IC) to demonstrate that they react in response to dsRNAith an increased expression of the (2-5)A synthetase gene

Materials and methods

1 Chemicals materials and enzymes

The sources of most chemicals and enzymes used wereiven earlier (Krasko et al 2000 Schroder et al in press)olyinosinic acidndashpolycytidylic acid [poly(IC)] polyinosiniccidndashpotassium salt [poly(I)] and polycytidylic acidndashpotassiumalt [poly(C)] were obtained from Sigma (Taufkirchen

unchen Germany) Lake Baikal water was obtained fromLakerdquo Comp (Irkutsk Russia)

2 Sponges and primmorphs

Live specimens of L baicalensis (Porifera Demospongiaeaplosclerida) were collected in Lake Baikal (Russia) from annpolluted natural site (near the village of Listvianka)

Primmorphs were prepared as described (Muller et al006a) In brief cells were obtained by dissociation with 50 mMthylenediaminetetraacetic acidndashNa salt (EDTA) After 40 minhe supernatant was collected and filtered through a 40 m meshylon net The single cells were harvested by centrifugationnd resuspended in Baikal water supplemented with penicillinnd streptomycin A cell suspension of 107 cells was added toml (final volume) of medium in 10 ml flasks (Nuclon sur-

ace 136196 Nunc Wiesbaden [Germany]) Primmorphs werebtained from these single cells they reached sizes of 3ndash7 mmfter 2 days For the experiment primmorphs were kept for 2ays at 16 C As indicated the primmorphs remained withoutoly(IC) or were treated for 2 days with 5 gml of poly(IC)

3 Tissue extract

Tissue samples of 10 g from L baicalensis were homogenizedn lysis-buffer (1times TBS [Tris-buffered saline] pH 75 1 mMDTA 1 Nonidet-P40 10 mM NaF 1 mM sodium ortho-

anadate and protease inhibitor mixture [Roche Mannheimermany]) After centrifugation (10000 times g 5 min) the super-atants were collected and used for the identification andurification of the enzyme

ar Im

2

riRFa(stcssTwsui

2o

niaotpdndTrtmpawAdcmtb

2o

(nwanp

wIcfw

2c

itsmtT4a

2

lfe(1a

fRsb(t1gcmrT

2b

pct5Htw

HC Schroder et al Molecul

4 Synthesis of iron oxide colloids

Ferrimagnetic iron oxide nanoparticles were synthesized atoom temperature by co-precipitation of ferrous and ferric ionsn sodium hydroxide solution as reported (Kang et al 1996)outinely an aqueous solution of Fe ions at a molar ratio ofe(II)Fe(III) of sim05 was prepared by dissolving 325 g FeCl3nd 20 g FeCl2middot4xH2O powders in 60 ml of acidified water50 ml deionized water and 10 ml of 1 M HCl) The resultingolution was added drop wise into 100 ml of a 1 M NaOH solu-ion under vigorous stirring resulting in the formation of blackolloidal particles The reaction was carried out in an inert atmo-phere under nitrogen for a period of 30 min The colloidalolution obtained was collected by centrifugation at 10000 times ghe sediment was washed with deionized water The solutionas then dispersed in 500 ml of water A portion of the synthe-

ized iron colloid solution was dried for further characterizationsing transmission electron microscopy (TEM Schroder et aln press)

5 Preparation of polymer coated ferromagnetic ironxide nanoparticles

In order to provide functionality and stability to iron oxideanoparticles a multifunctional statistical copolymer contain-ng two different functionalities was used (i) dopamine servings a robust anchor group capable of binding to many metalxides and (ii) free amine groups for a covalent binding ofhe phosphate groups present in the nucleic acid polymeroly(pentafluoro-phenylacrylate) [PFA poly(active ester)] asescribed (Eberhardt et al 2005) In brief 10 mg of iron oxideanoparticles were treated with 50 mg of the reactive polymerissolved in NN-dimethylformamide (DMF SigmandashAldrich)he reaction was carried out under vigorous mechanical stir-

ing at 40 C for 12 h followed by cooling the reaction systemo room temperature To remove unbound polymer the coated

agnetic particles in the solution were extracted by a magneticarticle concentrator (Dynal MPC1-50 Dynal Biotech France)t room temperature The resulting magnetic nanoparticles wereashed with DMF to ensure the removal of unreacted polymerportion of the washed magnetic nanoparticles was freeze-

ried for subsequent characterization using TEM The averagerystallite size of particles with and without functional poly-er coating was estimated by TEM Finally the suspension was

ransferred and dispersed in an aqueous 01 M methyl imidazoleuffer ([MELM] pH 75 Fluka)

6 dsRNA poly(IC) binding to amine functionalized ironxide nanoparticles

The procedure applied here has been recently publishedShukoor et al 2007) In brief double-stranded RNA polyi-osinic acidmiddotpolycytidylic acid [poly(IC)] was functionalized

ith 1-ethyl-3-[3-dimethylamino-propyl] carbodiimide (EDC)

nd coupled to iron oxide nanoparticles To ensure that allanoparticles reacted with poly(IC) an aliquot of the sus-ension was subjected to agarose gel electrophoresis The gel

oPPa

munology 45 (2008) 945ndash953 947

as stained in ethidium bromide and inspected with a Trans-lluminator (BIO-RAD Munchen Germany) Samples whichontained particles that did not migrate into the gel were used forurther experiments A portion of the washed magnetic particlesas freeze-dried for subsequent characterization using TEM

7 Incubation of sponge extract with poly(IC)-iron oxideonjugated nanoparticles

Sponge extract (800 l containing 100 g of protein) wasncubated with 200 l of poly(IC)-nanoparticles for 30 mino allow binding of poly(IC)-interacting proteins Then theamples were subjected to a magnetic field to concentrate theagnetic nanoparticles as outlined by Shukoor et al (2007)

hey were washed twice with PBS (phosphate buffered saline)o remove the interacting protein the samples were treated withM urea (pH 70) for 30 min The supernatant was collected andnalyzed by NaDodSO4-PAGE

8 NaDodSO4-PAGE and Western blot analysis

Samples containing 1ndash3 g of protein were dissolved inoading buffer (Roti-Load Roth Karlsruhe Germany) boiledor 5 min and then subjected to 10 polyacrylamide gellectrophoresis containing 01 sodium dodecyl sulphateNaDodSO4-PAGE) After separation the gels were washed in0 methanol (supplemented with 7 acetic acid) for 30 minnd then stained in Coomassie brilliant blue

For Western blot analysis the polypeptides were transferredrom the polyacrylamide gel to a nitrocellulose membrane (Bio-ad Munchen Germany [162-0112]) using the Trans-Blot SD

ystem (Bio-Rad) The membrane was rinsed in TBS and incu-ated for 1 h with polyclonal anti-(2-5)A synthetase antibodiesPoAb from rabbits [PoAb-25OAS see below] 11000 dilu-ion) After washing in TBS the membranes were incubated forh with anti-rabbit IgG (alkaline phosphatase conjugate fromoat Sigma) The immunocomplexes were visualized with theolor develop system NBTBCIP (Roth) In a control experi-ent 100 l of the PoAb-25OAS was adsorbed with 01 mg of

ecombinant (2-5)A synthetase for 30 min at 4 C prior to usehis preparation did not react with protein(s) on the blot

9 Cloning of a cDNA encoding the putative Laicalensis (2-5)A synthetase

The complete sponge LB2-5OAS cDNA was cloned byolymerase chain reaction (PCR) from the L baicalensisDNA library in TriplEx2 vector (BD Biosciences Clon-ech Palo Alto CA USA) The degenerate reverse primerprime-YGYHGGRTYIGCIGGRTC-3prime (where I = inosine Y = TC= TAC R = AG) in conjunction with the TriplEx2 vec-

or 5prime-end vector-specific forward primer was used This primeras designed against the conserved amino acid (aa) segment

f the signature-2 between aa302 and aa307 (Asp-Pro-Ala-Asp-ro-Thr) in the mouse (2-5)A synthetase I (accession number11928) Completion of the cDNA was achieved by PCR using3prime-end vector specific primer and internal LB2-5OAS specific

9 ar Im

pf57aLt

2

((waom(t1as1

2a

eErwGp3vteinpm0ldquo

fifaptt

2

iw

2tuldquotwfiDptjw(

2

mUumoftcSADou(Ilsp

2

e

3

3f

sor(s

48 HC Schroder et al Molecul

rimers PCR were carried out at an initial denaturation at 95 Cor 5 min followed by 35 amplification cycles at 95 C for 30 s6 C for 25 s 70 C for 15 min and a final extension step at0 C for 10 min Fragments of the expected size were obtainednd sequenced using standard procedures The clone encoding baicalensis LB2-5OAS is 1154 nucleotides long (excluding

he poly(A) tail)

10 Sequence analyses

The sequence was analyzed with computer programs BLAST2005 httpwwwncbinlmnihgovblastblastcgi) and FASTA2005 httpwwwebiacukfasta33) Multiple alignmentsere performed with CLUSTAL W Ver 16 (Thompson et

l 1994) Phylogenetic trees were constructed on the basisf aa sequence alignments by neighbour-joining as imple-ented in the ldquoNeighborrdquo program from the PHYLIP package

Felsenstein 1993) The distance matrices were calculated usinghe Dayhoff PAM matrix model as described (Dayhoff et al978) The degree of support for internal branches was furtherssessed by bootstrapping (Felsenstein 1993) The graphic pre-entations were prepared with GeneDoc (Nicholas and Nicholas997)

11 Recombinant sponge (2-5)A synthetase and raising ofntibodies

The sponge L baicalensis LB2-5OAS sequence wasxpressed with pTrcHis2-TOPO vector (Invitrogen) inscherichia coli cells strain TOP10 The complete open

eading frame (ORF) without start Met (nt37 to nt975)as isolated by PCR using one forward primer (5prime-CGGCGTCTGCGCATAGCGTGGTT-3prime) and one reverserimer (5prime-ATCCAAGGAAGTCGTTAAATCAAGACTGC-prime) The 939 bp long segment was cloned into the expressionector pTrcHis2-TOPO which contains at the 3prime-terminushe myc epitope and the polyhistidine region The insert wasxpressed overnight at 30 C in the presence of 01 mM ofsopropyl-beta-d-thiogalactopyranoside (IPTG) The recombi-ant protein was extracted and purified applying the Hismiddottagurification kit (Novagen Madison WI USA) The purity of theaterial was checked by 14 polyacrylamide gels containing

1 NaDodSO4 (PAGE) according to Laemmli (1970) thePrecision Plus Protein Standardsrdquo (Bio-Rad) were used

Polyclonal antibodies (PoAb) were raised against the puri-ed recombinant L baicalensis 25OAS LUBAI protein inemale rabbits (White New Zealand) as described (Schutze etl 2001) Ten micrograms of recombinant (2-5)A synthetaseer injection were dissolved in PBS and the animals boostedhree times The serum was collected the PoAb preparation wasermed PoAb-25OAS

12 In situ hybridization

Sponge tissue was embedded in Tissue-Tek and kept insopentane before cutting In situ hybridization was performedith digoxigenin-labeled (DIG) ssDNA probes (Perovic et al

s52h

munology 45 (2008) 945ndash953

003) Labeling was carried out with the ldquoPCR DIG Probe Syn-hesis Kitrdquo (Roche) The DNA oligonucleotide LB2-5OAS probesed was 264 bp long (nt172 and nt436) Thick cryosections (onSilane-prep slidesrdquo) were fixed with paraformaldehyde Afterreatment with Proteinase K followed by fixation the sectionsere incubated with increasing concentrations of ethanol andnally with isopropanol The sections were hybridized withIG-labeled antisense ssDNA probes Sense probes were used inarallel as negative controls in the experiments After blockinghe sections were incubated with an anti-DIG antibody con-ugated with alkaline phosphatase Hybridization was detectedith the dye reagent NBTX-Phosphate in 100 mM Tris-buffer

pH 95 100 mM NaCl 50 mM MgCl2)

13 RNA preparation and Northern blot analysis

RNA was extracted from liquid-nitrogen pulverized prim-orphs with TRIzol Reagent (GibcoBRL Grand Island NYSA) as described (Grebenjuk et al 2002) and then re-purifiedsing the SNAP Total RNA Isolation Kit (Invitrogen) Fiveicrograms of total RNA each was electrophoresed and blotted

nto a Hybond-N+ nylon membrane (Amersham Little Chal-ont Buckinghamshire UK) Hybridization was performed withhe (2-5)A synthetase probe (LB2-5OAS nt172 and nt436 of theDNA) The probes were labeled with the PCR-DIG-Probe-ynthesis Kit according to the ldquoInstruction Manualrdquo (Roche)fter washing DIG-labeled nucleic acid was detected with anti-IG Fab fragments [conjugated to alkaline phosphatase dilutionf 110000] and visualized by chemiluminescence techniquesing CDP according to the instructions of the manufacturerRoche) The screens were scanned with the GS-525 Molecularmager (Bio-Rad) In one series of experiments the RNA wasoaded onto the gels to demonstrate the equalization of the RNAamples used for the analysis staining of the agarose gel waserformed with ethidium bromide (1 gml)

14 Analytical technique

Protein concentrations were determined as described (Lowryt al 1951) using bovine serum albumin as standard

Results

1 Cloning of the cDNA encoding the (2-5)A synthetaserom L baicalensis

The complete sponge LB2-5OAS cDNA was isolated andequenced from a L baicalensis cDNA library The sequencebtained is 1154 nucleotides long and comprises one ORF whichanges from nt35ndash37 to nt977ndash979(stop) The deduced polypeptide25OAS LUBAI) comprises 314 aa (Fig 1A) the calculatedize is 35748 Da with a theoretical pI of 812 Highest sequence

imilarity was found with the two isoforms of the putative (2-)A enzymes from S domuncula (ldquoexpect valuerdquo (Coligan et al000) of 1eminus45) and from G cydonium (2eminus7) as well as to theuman (2-5)A synthetase-1 (4eminus06) Fig 1A

HC Schroder et al Molecular Immunology 45 (2008) 945ndash953 949

Fig 1 L baicalensis (2-5)A synthetase (A) The deduced protein of the L baicalensis sequence (25OAS LUBAI) was aligned with the S domuncula putative (2-5)A synthetase-1 (25OAS1 SUBDO CAC829331) the (2-5)A synthetase from G cydonium (25OAS GEOCY CAB380271) and the human (2-5)A synthetase-1(25OAS1 HOMO P00973) Residues conserved (similar or related with respect to their physico-chemical properties) in all sequences are shown in white on blackand those in at least three sequences in white on gray The characteristic sites in the sequences are marked the catalytic aspartic acid () the three residues in theactive site (sect) the 2prime-5prime-oligoadenylate synthase N-terminal region profile (sim25Asim) the poly(A) polymerase core region ([-PAP-]) and the nucleotidyltransferasedomain ((+NTP transf 2+)) Furthermore the two conserved signatures (|simSig-1 and |simSig-2) the potential ATP-binding region (|+ ATP) the dsRNA bindingsegment (-Bdg dsRNA) and the polyA-related domain (|polyA-related domain|) are indicated (B) A slanted phylogenetic tree was constructed after aligningthese sponge proteins with the second S domuncula (2-5)A synthetase-2 (25OAS2 SUBDO CAC829341) as well as with the related synthetases from human(25OAS1 HOMO P00973) isoform 2 [2prime-5prime-oligoadenylate synthetase 2 6971 kDa] (25OAS2 HOMO AAH492151) isoform 3 [2prime-5prime-oligoadenylate synthetase3 p100] (25OAS3 HOMO Q9Y6K5) and the human poly(A) polymerase alpha (PAP HUMAN NP 1160212) (C) Recombinant L baicalensis (2-5)A synthetaseThe cDNA was was expressed in E coli as described under Section 2 The fusion protein was extracted and analyzed by NaDodSO4-PAGE (lane a) the dominant4 e mar

dT25pm2f(tat1d

dapsc

maamL

0 kDa protein was purified by affinity chromatography (lane b) M protein siz

Search of domains was performed using the Motif Scanatabase (httpmyhitsisb-sibchcgi-binmotif scan ExPASy)he following characteristic regions have been identified theprime-5prime-oligoadenylate synthase N-terminal region profile [(2-)A SYNTH 3 MATRIX] ranging from aa40 to aa72 theolyA-related domain found in enzymes such as poly(A) poly-erase (2-5)A synthetase and topoisomerase I (Isrec-Server

001) from aa169 to aa211 and the nucleotidyltransferase domainrom aa18 to aa66 In addition the L baicalensis putative2-5)A synthetase comprises the two characteristic (2-5)A syn-hetase signatures (Hartmann et al 1998) signature-1 between

a195 and aa207 and signature-2 from aa264 to aa273 The puta-ive ATP-binding site the substrate binding site (Suhadolnik994 Isrec-Server 2001) resides between aa299 and aa207 ThesRNA binding region of the (2-5)A synthetase can be narrowed

htpw

kers

own between aa87 and aa130 (Suhadolnik 1994 Hartmann etl 1998 2003) Finally the three catalytic Asp residues atositions 58 60 and 122 and the three residues in the activeite Ser-46 SerLeu-47 and Lys-176 (Hartmann et al 2003) areonserved in the L baicalensis sequence Fig 1A

A phylogenetic tree was constructed with the above-entioned sequences and the additional human isoforms as well

s with the more distantly related human poly(A) polymeraselpha and the two isoforms from S domuncula After align-ent a slanted tree was constructed (Fig 1B) It shows that the baicalensis sequence falls in the branch together with the other

itherto known sponge sequences more distantly related are thehree human isoforms with ndash as expected ndash the human poly(A)olymerase alpha on the basis of the tree No invertebrate proteinith a significant similarity (lteminus01) could be included

9 ar Immunology 45 (2008) 945ndash953

3a

aai((s(

3n

orftgpaptta

3e

NmscsNbust

(rWtPsnb

3s

b

Fig 2 Isolation and identification of L baicalensis (2-5)A synthetase (A) Iso-lation of the (2-5)A synthetase by NaDodSO4-PAGE (Lane a) A crude extractwas prepared and separated by gel electrophoresis (Lane b) The crude extractwas supplemented with poly(IC)-iron oxide conjugated nanoparticles and afterseparation of the particles in a magnetic field and following elution of the asso-ciated proteins the soluble molecules were size separated The gels were stainedwith Coomassie brilliant blue M a size marker was run in parallel (B) Westernblot analysis of the fraction obtained after separation with poly(IC)-iron oxideconjugated nanoparticle This fraction was subjected to NaDodSO4-PAGE fol-lowed by a transfer of the proteins to a membrane which was finally reacted withPoAb-25OAS antibodies The immunocomplexes were identified with labeledsecondary antibodies The 35 kDa protein can be identified in the poly(IC)-ironoxide-nanoparticle fraction after desorption with urea (lane a) In a separateWwi

siicsts

3p

ost(

50 HC Schroder et al Molecul

2 Recombinant (2-5)A synthetase and respectiventibodies

The L baicalensis (2-5)A synthetase was expressed in E colis described under Section 2 The fusion protein was extractednd analyzed by NaDodSO4-PAGE (Fig 1C lane a) The dom-nant 40 kDa protein was purified by affinity chromatographyFig 1C lane b) This hybrid protein is composed of the 36 kDa2-5)A synthetase and the 4 kDa large myc and polyhistidineegments Finally antibodies were raised against the purified2-5)A synthetase (PoAb-25OAS)

3 Synthesis and characterization of poly(IC)-iron oxideanoparticles

At first iron oxide colloids composed of ferrimagnetic ironxide nanoparticles were prepared by co-precipitation of fer-ous and ferric ions The resulting iron colloid particles wereunctionalized with the reactive polymer PFA After purifica-ion the derivatized nanoparticles comprising the formed amineroups were allowed to bind to the 5prime-end of the poly(IC)olymer applying phosphoramidate chemistry (Shukoor etl 2007) The preparation obtained contained no unboundoly(IC) as checked by agarose gel electrophoresis (see Sec-ion 2) TEM analysis showed that under the conditions usedhe non-derivatized ferrimagnetic iron oxide nanoparticles haven average size of 10ndash12 nm (see Shukoor et al 2007)

4 Isolation of (2-5)A synthetase incubation of spongextract with poly(IC)-iron oxide conjugated nanoparticles

Tissue from L baicalensis was extracted and analyzed byaDodSO4-PAGE (Fig 2A lane a) If this extract was supple-ented with poly(IC)-iron oxide conjugated nanoparticles and

ubjected after incubation to a magnetic field the nanoparticlesould be recovered Proteins bound to the particles were dis-olved with urea the particle-free preparation was analyzed byaDodSO4-PAGE (Fig 2A lane b) After separation a clearand with a size of 35 kDa could be visualized This molec-lar weight corresponds to the calculated size of the (2-5)Aynthetase deduced from the cloned L baicalensis (2-5)A syn-hetase cDNA [35748 Da]

To verify that the separated 35 kDa polypeptide represents the2-5)A synthetase antibodies (PoAb-25OAS) which had beenaised against the recombinant sponge protein were applied for

estern blotting With this probe a clear cross-reactivity withhe 35 kDa could be visualized (Fig 2B lane a) As a controloAb-25OAS were adsorbed with recombinant sponge (2-5)Aynthetase This antibody preparation did not show any sig-ificant cross-reactivity to a protein on the blot (Fig 2B lane)

5 In situ localization of cells expressing (2-5)A

ynthetase in tissue

Fresh tissue from L baicalensis was cryosectioned followedy in situ hybridization of the sections using the antisense (2-5)A

tbpg

estern blotting experiment the membranes were reacted with PoAb-25OAShich had been adsorbed with recombinant (2-5)A synthetase [ads] no signal

s seen (lane b)

ynthetase probe the probe was DIG-labeled to allow visual-zation of hybridization signals using anti-DIG antibodies Themages show (see example in Fig 3A) that especially around theanals the cells are brightly stained As a control correspondinglices were reacted with a DIG-labeled sense ssDNA probe Inhose samples the cells around the canals show only a weakignal (Fig 3B)

6 Induction of sponge (2-5)A synthetase in response tooly(IC)

Primmorphs were exposed to 5 gml of poly(IC) for peri-ds of 1 or 2 days Then RNA was extracted size separated andubjected to Northern blot hybridization Using the (2-5)A syn-hetase probe transcripts with a size of 12 kb could be identifiedFig 4A) The level of expression in samples not treated with

he dsRNA remained almost constant during the 2-days incu-ation period (Fig 4A upper panel) while animals exposed tooly(IC) responded with an up-regulation of (2-5)A synthetaseene expression (Fig 4A lower panel) the steady-state level

HC Schroder et al Molecular Immunology 45 (2008) 945ndash953 951

F waso probs

afTishpoo

4

wi

Fwutasdlg

Tia[bfOrtai

ig 3 Expression of (2-5)A synthetase in tissue from L baicalensis analysisf the sponge (A) Cryosection hybridized with an antisense (2-5)A synthetaseynthetase probe The aquiferous canal is marked (ca)

fter 1 day exposure was 27-fold higher and after 2 days 47-old higher than the signal determined at day 0 (set to 1-fold)o verify that (almost) the same amount of RNA was loaded

n all lanes the RNA was stained in the agarose gel after sizeeparation (Fig 4B) In controls to poly(IC) parallel studiesad been performed with 1 5 or 10 gml of either poly(I) oroly(C) After a 2-days incubation period no significant changef the steady-state level of expression of (2-5)A synthetase wasbserved after Northern blot hybridization (not shown)

Discussion

Earlier it was found that sponges are also equippedith genomic regulatory systems allowing complex arrays of

mmune responses including those towards microorganisms

ig 4 Expression of sponge (2-5)A synthetase gene in response to incubationith poly(IC) (A) In one series of experiments the primmorphs remainedntreated [minus poly(IC)] (upper panel) while in parallel assays the cells werereated with this polymer [plus poly(IC)] (lower panel) RNA was extractedt day 0 (lane a left) day 1 (lane b middle) and day 2 (lane c right) andize fractioned and then hybridized with a labeled (2-5)A synthetase probe asescribed in Section 2 (B) To verify that equal amounts of RNA (5 g) wereoaded onto the gel RNA was stained with ethidium bromide in a parallel agaroseel [plus poly(IC)] the positions of the 28S and 18S rRNA are marked

(vsavktl

gdwdt(pttaH(astvt

wTbf

performed by in situ hybridization Cross-sections were prepared from tissuee as described under Section 2 (B) Section hybridized with the sense (2-5)A

he immune defense systems are highly related to those foundn vertebrates (Muller et al 1999a Muller 2005) among themre the defense systems directed against gram-positive bacteriapeptidoglycan recognition (Thakur et al 2005)] gram-negativeacteria [perforin-responsive defense (Wiens et al 2005)] andungi [(1-3)--d-glucan receptor mediated defense (Perovic-ttstadt et al 2004)] Recently the existence of the innate

esponse system including the Toll-like receptor could be iden-ified as well (Wiens et al 2007) Since sponges live in anqueous environment they are exposed also to a viral load thats more complex and higher than in the terrestrial environmentBergh et al 1989) The only hitherto identified suspected anti-iral defense system known from sponges involves the (2-5)Aynthetase The product of this enzyme is 2-5A which mightctivate the latent RNase L In turn this nuclease degrades bothiral and cellular RNA (see Section 1) Until now it was notnown if the sponge (2-5)A synthetase has the potency to bindo dsRNA a process which is required for the conversion of theatent to the active form in higher invertebrates

In the present study we asked whether (i) the L baicalensisenome contains and expresses ndash like in the marine sponges Somuncula and G cydonium ndash the (2-5)A synthetase and (ii)hether this (2-5)A synthetase binds to dsRNA By PCR withegenerate primers designed against the conserved region ofhe mammalian (2-5)A synthetase the respective L baicalensis2-5)A synthetase was identified and sequenced The deducedolypeptide with a size of 36 kDa comprises the characteris-ic features known also from vertebrate (2-5)A synthetases eghe ATP-binding site the dsRNA-association region and the cat-lytic amino acid moieties (reviewed in Eskildsen et al 2002artmann et al 2003) Like the enzymes from G cydonium

Wiens et al 1999) and S domuncula (Grebenjuk et al 2002)lso the L baicalensis (2-5)A synthetase belongs to the (2-5)Aynthetases I This finding underscores earlier propositions thathe sponge enzymes share a direct common ancestor with theertebrate (2-5)A synthetases with the (2-5)A synthetase I ashe evolutionary oldest representative (Wiens et al 1999)

The purpose of isolating the L baicalensis (2-5)A synthetase

as to clarify the (potential) affinity of this enzyme to dsRNAherefore we applied ferrimagnetic nanoparticles which hadeen linked to poly(IC) as a tool to isolate the (2-5)A synthetaserom the crude extract The technology for the preparation of

HC Schroder et al Molecular Immunology 45 (2008) 945ndash953 951

F waso probs

afTishpoo

4

wi

Fwutasdlg

Tia[bfOrtai

ig 3 Expression of (2-5)A synthetase in tissue from L baicalensis analysisf the sponge (A) Cryosection hybridized with an antisense (2-5)A synthetaseynthetase probe The aquiferous canal is marked (ca)

fter 1 day exposure was 27-fold higher and after 2 days 47-old higher than the signal determined at day 0 (set to 1-fold)o verify that (almost) the same amount of RNA was loaded

n all lanes the RNA was stained in the agarose gel after sizeeparation (Fig 4B) In controls to poly(IC) parallel studiesad been performed with 1 5 or 10 gml of either poly(I) oroly(C) After a 2-days incubation period no significant changef the steady-state level of expression of (2-5)A synthetase wasbserved after Northern blot hybridization (not shown)

Discussion

Earlier it was found that sponges are also equippedith genomic regulatory systems allowing complex arrays of

mmune responses including those towards microorganisms

ig 4 Expression of sponge (2-5)A synthetase gene in response to incubationith poly(IC) (A) In one series of experiments the primmorphs remainedntreated [minus poly(IC)] (upper panel) while in parallel assays the cells werereated with this polymer [plus poly(IC)] (lower panel) RNA was extractedt day 0 (lane a left) day 1 (lane b middle) and day 2 (lane c right) andize fractioned and then hybridized with a labeled (2-5)A synthetase probe asescribed in Section 2 (B) To verify that equal amounts of RNA (5 g) wereoaded onto the gel RNA was stained with ethidium bromide in a parallel agaroseel [plus poly(IC)] the positions of the 28S and 18S rRNA are marked

(vsavktl

gdwdt(pttaH(astvt

wTbf

performed by in situ hybridization Cross-sections were prepared from tissuee as described under Section 2 (B) Section hybridized with the sense (2-5)A

he immune defense systems are highly related to those foundn vertebrates (Muller et al 1999a Muller 2005) among themre the defense systems directed against gram-positive bacteriapeptidoglycan recognition (Thakur et al 2005)] gram-negativeacteria [perforin-responsive defense (Wiens et al 2005)] andungi [(1-3)--d-glucan receptor mediated defense (Perovic-ttstadt et al 2004)] Recently the existence of the innate

esponse system including the Toll-like receptor could be iden-ified as well (Wiens et al 2007) Since sponges live in anqueous environment they are exposed also to a viral load thats more complex and higher than in the terrestrial environmentBergh et al 1989) The only hitherto identified suspected anti-iral defense system known from sponges involves the (2-5)Aynthetase The product of this enzyme is 2-5A which mightctivate the latent RNase L In turn this nuclease degrades bothiral and cellular RNA (see Section 1) Until now it was notnown if the sponge (2-5)A synthetase has the potency to bindo dsRNA a process which is required for the conversion of theatent to the active form in higher invertebrates

In the present study we asked whether (i) the L baicalensisenome contains and expresses ndash like in the marine sponges Somuncula and G cydonium ndash the (2-5)A synthetase and (ii)hether this (2-5)A synthetase binds to dsRNA By PCR withegenerate primers designed against the conserved region ofhe mammalian (2-5)A synthetase the respective L baicalensis2-5)A synthetase was identified and sequenced The deducedolypeptide with a size of 36 kDa comprises the characteris-ic features known also from vertebrate (2-5)A synthetases eghe ATP-binding site the dsRNA-association region and the cat-lytic amino acid moieties (reviewed in Eskildsen et al 2002artmann et al 2003) Like the enzymes from G cydonium

Wiens et al 1999) and S domuncula (Grebenjuk et al 2002)lso the L baicalensis (2-5)A synthetase belongs to the (2-5)Aynthetases I This finding underscores earlier propositions thathe sponge enzymes share a direct common ancestor with theertebrate (2-5)A synthetases with the (2-5)A synthetase I ashe evolutionary oldest representative (Wiens et al 1999)

The purpose of isolating the L baicalensis (2-5)A synthetase

as to clarify the (potential) affinity of this enzyme to dsRNAherefore we applied ferrimagnetic nanoparticles which hadeen linked to poly(IC) as a tool to isolate the (2-5)A synthetaserom the crude extract The technology for the preparation of

9 ar Im

t2bc53wpatalb

iattswii

swmtifei(([tctm(drTtmshmp(istk

tis

(c(

A

FuBTt

R

A

B

BB

C

D

D

D

E

E

FFG

G

H

H

H

52 HC Schroder et al Molecul

hese particles has recently been described (Shukoor et al007) Using this polymer as a probe a 35 kDa protein coulde isolated from the extract In order to verify that this proteinorresponds to L baicalensis (2-5)A synthetase the sponge (2-)A synthetase recombinant protein with the predicted size of5748 Da was prepared and antibodies were raised By their usee could demonstrate by Western blot analysis that the 35 kDarotein identified by NaDodSO4-PAGE cross-reacted with thentibodies These molecular and biochemical data demonstratehat the (2-5)A synthetase gene is present in the sponge genomend is expressed in the living organism Furthermore the iso-ation procedure shows that the sponge protein displays stronginding ability to dsRNA

This finding has important implications for the understand-ng of the evolution of the metazoan immune system to protectgainst viral load As outlined in the Section 1 the (2-5)A syn-hetase system has been ndash until now ndash exclusively found inhe Porifera (sponge)-Deuterostomia lineage However recenttudies with marine crustaceans show that shrimps if treatedith dsRNA respond with an increased resistance against viral

nfection (Robalino et al 2004) suggesting the existence of annterferon-related system in these invertebrates

In a further series of experiments primmorphs which are apecial form of two-dimensional cell culture from L baicalensisere treated with the dsRNA poly(IC) to clarify if the ani-als are able to respond to these polymers After treatment

he expression level of the (2-5)A synthetase gene stronglyncreased reflecting that sponges have the recognition systemor poly(IC) in their cells From our recent studies we couldstablish that sponges are provided with two molecules knownn mammals to be required for dsRNA responsiveness These arei) the Toll-like receptor (TLR) identified from S domunculaWiens et al 2007) and (ii) IL-1 receptor-associated kinasesIRAKs] (Wiens et al 2007) Specifically TLR3 is known to behe recognizing receptor for dsRNApoly(IC) on mammalianell surfaces (Alexopoulou et al 2001 Hiscott 2004) A fur-her molecule interacting with a Toll-like receptor (TLR4) the

yeloid differentiation factor 88 (MyD88)-like adapter proteinMcGettrick and OrsquoNeill 2004) was identified in the sponge Somuncula (Wiens et al 2005) Since the S domuncula Toll-likeeceptor forms in a phylogenetic tree the basis for the receptorsLR1ndashTLR10 identified both in Protostomia and in Deuteros-

omia it may be assumed that the sponge Toll-like receptoright respond to dsRNA as well A further possibility is that

ponges comprise an array of different TLRs some of whichave perhaps a closer relationship to mammalian TLR3 Untilore sequence data become available from sponges we pro-

ose that the observed up-regulation of the gene coding for the2-5)A synthetase is a result of an IFN-related molecule thatnteracts (indirectly) with a TLR molecule on the sponge cellurface and elicits intracellular signaling processes involvingyrosine kinases and the recruitment of phosphatidyl-inositol-3inase and the TANK-binding kinase (Hiscott 2004)

Taken together the data presented show that members ofhe evolutionary oldest metazoan phylum the Porifera possessmmune-defense systems which can recognize bacteria and asuggested here also viruses In addition the cytokine-dependent

H

I

munology 45 (2008) 945ndash953

2-5)A synthetase system might have functions in the control ofell proliferation and differentiation as has been proposed earlierShimizu and Sokawa 1979)

cknowledgements

This work was supported by grants from the Deutscheorschungsgemeinschaft the Bundesministerium fur Bildungnd Forschung Germany [project Center of ExcellenceIOTECmarin] the European Union (MCRTN ldquoBIOCAPI-ALrdquo) the European Society for Marine Biotechnology andhe International Human Frontier Science Program

eferences

lexopoulou L Holt CA Medzhitov R Flavell RA 2001 Recognitionof double-stranded RNA and activation of NF-B by Toll-like receptor 3Nature 413 732ndash738

ergh O Borsheim KY Bratbak G Heldal M 1989 High abundance ofviruses found in aquatic environments Nature 340 467ndash468

LAST 1997 httpwwwncbinlmnihgovblastblastcgi Internetlumbach B Diehl-Seifert B Seack J Steffen R Muller IM Muller

WEG 1999 Cloning and expression of new receptors belonging to theimmunoglobulin superfamily from the marine sponge Geodia cydoniumImmunogenetics 49 751ndash763

oligan JE Dunn BM Ploegh HL Speicher DW Wingfield PT 2000Current Protocols in Protein Science John Wiley and Sons Chichester pp201ndash2817

ayhoff MO Schwartz RM Orcutt BC 1978 A model of evolutionarychange in protein In Dayhoff MO (Ed) Atlas of Protein Sequence andStructure Nat Biomed Res Foundation Washington DC pp 345ndash352

er SD Zhou A Williams BRG Silverman RH 1998 Identification ofgenes differentially regulated by interferon or using oligonucleotidearrays Proc Natl Acad Sci USA 95 5623ndash15628

ong B Silverman RH 1995 2-5A-dependent RNase molecules dimerizeduring activation by 2-5A J Biol Chem 270 4133ndash4137

berhardt M Mruk R Theato P Zentel R 2005 Synthesis of pentafluo-rophenyl(meth)acrylate polymers new precursor polymers for the synthesisof multifunctional materials Eur Polym J 41 1569ndash1575

skildsen S Hartmann R Kjeldgaard NO Justesen J 2002 Gene structureof the murine 2prime-5prime-oligoadenylate synthetase family Cell Mol Life Sci 591212ndash1222

ASTA 2005 httpwwwebiacukfasta33html Internetelsenstein J 1993 PHYLIP ver 35 University of Washington Seattlehosh SK Kusari J Bandyopadhyay SK Samanata H Kumar R Sen

GC 1991 Cloning sequencing and expression of two murine 2prime-5prime-oligoadenylate synthetases J Biol Chem 266 15293ndash15299

rebenjuk VA Kuusksalu A Kelve M Schutze J Schroder HC MullerWEG 2002 Induction of (2prime-5prime)oligoadenylate synthetase in the marinesponges Suberites domuncula and Geodia cydonium by the bacterial endo-toxin lipopolysaccharide Eur J Biochem 269 1382ndash1392

artmann R Noerby PL Martensen PM Joergensen P James MCJacobson C Moestrup SK Clemens MJ Justesen J 1998 Activationof 2-5 oligoadenylate synthetase by single-stranded and double-strandedRNA aptamers J Biol Chem 273 3236ndash3246

artmann R Justesen J Sarkar SN Sen GC Yee VC 2003 Crystalstructure of the 2prime-specific and double-stranded RNA-activated interferon-induced antiviral protein 2prime-5prime-oligoadenylate synthetase Mol Cell 191173ndash1185

iscott J 2004 Another detour on the Toll road to the interferon antiviral

response Nat Struct Mol Biol 11 1028ndash1030

ovanessian AG 1991 Interferon-induced and double-stranded RNA-activated enzymes a specific protein kinase and 2prime5prime-oligoadenylatesynthetase J Interferon Res 11 199ndash205

srec-Server 2001 Available from httphitsisb-sibchcgi-binPFSCAN

ar Im

K

K

K

K

L

L

M

M

M

M

M

M

M

M

M

M

M

M

M

N

P

P

P

R

S

S

S

S

S

S

SS

S

T

T

W

W

W

HC Schroder et al Molecul

ang YS Risbud S Rabolt JF Stroeve P 1996 Synthesis and charac-terization of nanometer-size Fe3O4 and -Fe2O3 particles Chem Mater 82209ndash2211

rasko A Batel R Schroder HC Muller IM Muller WEG 2000Expression of silicatein and collagen genes in the marine sponge Suberitesdomuncula is controlled by silicate and myotrophin Eur J Biochem 2674878ndash4887

uusksalu A Pihlak A Muller WEG Kelve M 1995 The (2prime5prime) oligoad-enylate synthetase presence in the lowest multicellular organisms the marinesponges demonstration of the existence and identification of its reactionproducts Eur J Biochem 232 351ndash357

uusksalu A Subbi J Pehk T Reintamm T Muller WEG Kelve M1998 (2prime-5prime)oligoadenylate synthetasee in marine sponge identification ofits reaction products Eur J Biochem 257 420ndash426

aemmli UK 1970 Cleavage of structural proteins during the assembly ofthe head of bacteriophage T4 Nature 227 680ndash685

owry OH Rosebrough NJ Farr AL Randall RJ 1951 Protein mea-surement with the folin phenol reagent J Biol Chem 193 265ndash275

anconi R Pronzato R 2000 Suborder Spongillina subord Nov freshwatersponges In Hooper JNA van Soest RWM (Eds) Systema Porifera AGuide to the Classification of Sponges Kluwer AcademicPlenum Publish-ers New York pp 921ndash1019

cGettrick AF OrsquoNeill LAJ 2004 The expanding family of MyD88-like adaptors in Toll-like receptor signal transduction Mol Immunol 41577ndash582

uller WEG 1997 Origin of metazoan adhesion molecules and adhesionreceptors as deduced from their cDNA analyses from the marine spongeGeodia cydonium Cell Tissue Res 289 383ndash395

uller WEG 2003 The origin of metazoan complexity Porifera as integratedanimals Integr Comp Biol 43 3ndash10

uller WEG 2005 Spatial and temporal expression patterns in animals InMeyers RA (Ed) Encyclopedia of Molecular Cell Biology and MolecularMedicine 13 WileyndashVCH GmbH Weinheim pp 269ndash309

uller WEG 2006 The stem cell concept in sponges (Porifera) metazoantraits Semin Cell Dev Biol 17 481ndash491

uller WEG Muller IM 2003 Origin of the metazoan immune systemidentification of the molecules and their functions in sponges Integr CompBiol 43 281ndash292

uller WEG Schroder HC (Eds) 1994 Biological ResponseModifiersmdashInterferons Double-Stranded RNA and 2prime5prime-OligoadenylatesSpringer-Verlag Berlin

uller WEG Blumbach B Muller IM 1999a Evolution of the innateand adaptive immune systems relationships between potential immunemolecules in the lowest metazoan phylum [Porifera] and those in vertebratesTransplantation 68 1215ndash1227

uller WEG Wiens M Batel R Steffen R Borojevic R Custodio MR1999b Establishment of a primary cell culture from a sponge Primmorphsfrom Suberites domuncula Mar Ecol Progr Ser 178 205ndash219

uller WEG Wiens M Adell T Gamulin V Schroder HC Muller IM2004 The bauplan of the Urmetazoa the basis of the genetic complexity ofmetazoa using the siliceous sponges [Porifera] as living fossils Int RevCytol 235 53ndash92

uller WEG Belikov SI Kaluzhnaya OV Perovic-Ottstadt S Fat-torusso E Ushijima H Krasko A Schroder HC 2006a Cold stressdefense in the freshwater sponge Lubomirskia baicalensis role of okadaicacid produced by symbiotic dinoflagellates FEBS J 274 23ndash36

uller WEG Schroder HC Wrede P Kaluzhnaya OV Belikov SI2006b Speciation of sponges in Baikal-Tuva region (an outline) J ZoolSyst Evol Res 44 105ndash117

icholas KB Nicholas Jr HB 1997 GeneDoc a tool for editing and anno-tating multiple sequence alignments Version 11004 Distributed by theauthor wwwcriscomsimketchupgenedocshtml Internet

erovic S Schroder HC Sudek S Grebenjuk VA Batel R StifanicM Muller IM Muller WEG 2003 Expression of one sponge Iroquois

W

munology 45 (2008) 945ndash953 953

homeobox gene in primmorphs from Suberites domuncula during canalformation Evol Dev 5 240ndash250

erovic-Ottstadt S Adell T Proksch P Wiens M Korzhev M GamulinV Muller IM Muller WEG 2004 A (1 rarr 3)--d-glucan recogni-tion protein from the sponge Suberites domuncula mediated activation offibrinogen-like protein and epidermal growth factor gene expression Eur JBiochem 271 1924ndash1937

ile AJ Patterson MR Savarese M Chernykh VI Fialkov VA 1997Trophic effects of sponge feeding within Lake Baikalrsquos littoral zone2 Sponge abundance diet feeding efficiency and carbon flux LimnolOceanogr 42 178ndash184

obalino J Browdy CL Prior S Metz A Parnell P Gross P Warr G2004 Induction of antiviral immunity by double-stranded RNA in a marineinvertebrate J Virol 78 10442ndash10448

chroder HC Ushijima H Krasko A Gamulin V Schutze J MullerIM Muller WEG 2003 Emergence and disappearance of an immunemolecule an antimicrobial lectin in basal metazoa the tachylectin familyJ Biol Chem 278 32810ndash32817

chroder HC Natalio F Shukoor I Tremel W Schloszligmacher U WangX Muller WEG in press Apposition of silica lamellae during growth ofspicules in the demosponge Suberites domuncula biologicalbiochemicalstudies and chemicalbiomimetical confirmation Struct Biol

chutze J Skorokhod A Muller IM Muller WEG 2001 Molecular evo-lution of metazoan extracellular matrix cloning and expression of structuralproteins from the demosponges Suberites domuncula and Geodia cydoniumJ Mol Evol 53 402ndash415

en GC Lengyel P 1992 The interferon system J Biol Chem 2675017ndash5020

himizu N Sokawa Y 1979 2prime5prime-Oligoadenylate synthetase activity in lym-phocytes from normal mouse J Biol Chem 254 12034ndash12037

hukoor MI Natalio F Ksenofontov V Tahir MN Eberhardt M TheatoP Schroder HC Muller WEG Tremel W 2007 dsRNA [poly IC]immobilized onto -Fe2O3 nanoparticles using a multifunctional polymericlinker Small 3 1374ndash1378

impson TL 1984 The Cell Biology of Sponges Springer-Verlag New Yorktark GR Kerr IM Williams BRG Silverman RH Schreiber RD

1998 How cells respond to interferons Annu Rev Biochem 67227ndash264

uhadolnik RJ 1994 Photolabeling of the enzyme of the 2-5A syn-thetaseRNase Lp68 kinase antiviral system with azido probes Prog MolSubcell Biol 14 260ndash275

hakur NL Perovic-Ottstadt S Batel R Korzhev M Diehl-Seifert BMuller IM Muller WEG 2005 Innate immune defense of the spongeSuberites domuncula against gram-positive bacteria induction of lysozymeand AdaPTin Mar Biol 146 271ndash282

hompson JD Higgins DG Gibson TJ 1994 CLUSTAL W improv-ing the sensitivity of progressive multiple sequence alignment throughsequence weighting positions-specific gap penalties and weight matrixchoice Nucleic Acids Res 22 4673ndash4680

ehrl M Steinert M Hentschel U 2007 Bacterial uptake by the marinesponge Aplysina aerophoba Microb Ecol 53 355ndash365

iens M Kuusksalu A Kelve M Muller WEG 1999 Origin of theinterferon-inducible (2prime-5prime)oligoadenylate synthetases cloning of the (2prime-5prime)oligoadenylate synthetase from the marine sponge Geodia cydoniumFEBS Lett 462 12ndash18

iens M Korzhev M Krasko A Thakur NL Perovic-Ottstadt S BreterHJ Ushijima H Diehl-Seifert B Muller IM Muller WEG 2005Innate immune defense of the sponge Suberites domuncula against bacteriainvolves a MyD88-dependent signaling pathway induction of a perforin-like

molecule J Biol Chem 280 27949ndash27959

iens M Korzhev M Perovic-Ottstadt S Luthringer B Brandt D KleinS Muller WEG 2007 Toll-like receptors are part of the innate immunedefense system of sponges (Demospongiae Porifera) Mol Biol Evol 24792ndash804