RNA VIRUSdrh. Sruti Listra Adrenalin, M.Sc.

3 Maret 2020

VIRUS

Virion : kesatuan partikel virus

F/ : mengirim genom RNA/DNA ke sel host u/ di ekspresikan (translasi, transkripsi) o/sel host

Kapsid : protein pelindung as. Nukleat, disandi genom

Nukleokapsid : gab kapsid + as.Nukleat

Kapsomer : Kapsid terbentuk dari banyak subunit protein

KLASIFIKASI VIRUS

1. Bentuk:

Ikosahedral, bentuk 20 segitiga sama sisi, dengan sumbu rotasi ganda. C/ virus polio, adenovirus, picornaviridae, Calicivirade, Togaviridae, Flaviviridae, Reoviridae, Retroviridae.

Heliks, menyerupai batang panjang, nukleokapsid tidak kaku dalam selaputpembungkus lipoprotein dan berbentuk heliks, memiliki satu sumbu rotasi. Contoh :Orthomyxoviridae, Paramyxoviridae, Filoviridae, Rhabdoviridae.

Kompleks, struktur sgt kompleks dan pada umumnya lebih lengkap dibandingdengan virus lainnya.

… KLASIFIKASI VIRUS

2. Selubung

Virus berselubung, mempunyai selubung yang tersusun atas lipoprotein atauglikoprotein. Contoh : Poxvirus, Herpesvirus, Orthomyxovirus, Paramyxovirus, Rhabdovirus, Togavirus, Retrovirus.

Virus tdk berselubung, Nukleokapsid tidak diselubungi oleh lapisan yang lain hanyamemiliki kapsid (protein) dan asam nukleat. Contoh : Adenovirus, Papovavirus, Parvovirus, Picornavirus, Reovirus.

3. Asam Nukleat

Virus DNA Contoh : Poxvirus, Hepesvirus, Adenovirus, Papovavirus, Parvovirus.

Virus RNA Contoh : Orthomyxoviruses, Paramyxoviruses, Rhabdoviruses, Picornaviruses, Togaviruses, Reoviruses, Retroviruses.

RNA vs DNA VIRUS

DNA RNA

Umumnya double stranded Single stranded

Kemampuan mutase lebih rendah Kemampuan mutase tinggi

Replikasi terjadi di nucleus Replikasi di sitoplasma

Sugar deoxyribose Sugar ribose

Stabil pd kondisi alkalin Tidak stabil

Basa: adenine-thymin (AT), cytocine-guanine (CG) Adenin-uracil (AU), cytocine-guanine (CG)

Self replicating RNA disintesis dari DNA berdasarkan kebutuhan

Bertanggung jawab terhadap penyimpanan dan transfer informasi genetic

Secara langsung mengkode asam amino dan sebagaimessenger antara DNA dan ribosom untuk membuatprotein

BALTIMORE CLASSIFICATION

RNA VIRUS

KLASIFIKASI BALTIMORE

RNA VIRUS 1

dsRNA (Class III):

1. Reoviridae

2. Birnaviridae

ssRNA (+) (class IV):

1. Coronaviridae

2. Flaviviridae

3. Caliciviridae

4. Picornaviridae

5. Togaviridae

RNA VIRUS 2

ssRNA (-) (Class V):

1. Bunyaviridae

2. Orthomyxoviridae

3. Filoviridae

4. Bornaviridae

5. Paramyxoviridae

6. Rhabdoviridae

ssRNA (RT) (Class VI):

1. Retroviridae

REOVIRIDAE

Virions are nonenveloped, spherical in outline, 5580 nm in diameter.

Virions are composed of three concentric capsid layers, all with icosahedral symmetry; the outer capsid differs in appearance in the various genera.

Genome is composed of double-stranded RNA

Cytoplasmic replication.

Genetic reassortment occurs between viruses within each genus or serogroup (genetic shift), along with mutation of individual genes (genetic drift).

… R

EOV

IRID

AE

BIRNAVIRIDAE

Virions are nonenveloped, hexagonal in outline, approximately 65 nm in diameter, single shell having icosahedral symmetry.

Genome consists of two molecules of linear double-stranded RNA.

A single major capsid protein, and one or more nonstructural proteins (RNA polymerase (transcriptase)).

Cytoplasmic replication.

Survives at 60°C for 60 min; stable at pH 3-9.

Birnaviruses occur in chickens (infectious bursal disease virus), salmonid fish (infectious pancreatic necrosis virus), and many species of marine fish and shellfish (aquatic birnaviruses) as well as reptiles, crustaceans, and insects.

CORONAVIRIDAE

Virions are pleomorphic or spherical (Subfamily Coronavirinae) or disc-, kidney-, or rod-shaped (Subfamily Torovirinae); 80220 nm-120140 nm in diameter. Virions are enveloped, with large club-shaped spikes (peplomers).

Virions have an icosahedral core structure within which is a helical nucleocapsid(coronaviruses) or a tightly coiled tubular nucleocapsid in a doughnut (toroviruses) or bacilliform (bafiniviruses) shape.

The genome consists of a single molecule of linear positivesense, single-stranded RNA, 2531 kb in size, and infectious.

Coronavirus virions contain structural proteins: a major spike glycoprotein (S), transmembrane glycoproteins (M and E), a nucleoprotein (N), and, in some viruses, a hemagglutinin esterase (HE).

Viruses replicate in the cytoplasm.

Virions are formed by budding into the endoplasmic reticulum and are released by exocytosis. Cell fusion may occur.

… C

OR

ON

AV

IRID

AE

… C

OR

ON

AV

IRID

AE

… C

OR

ON

AV

IRID

AE

FLAVIVIRIDAE

Flavivirus, mostly arthropod-borne viruses; Pestivirus, nonarthropod-borne, includes several veterinary pathogens; Hepacivirus, human hepatitis C virus and several related and newly identified viruses of animals of uncertain pathogenic significance; Pegivirus, including a group of newly identified human and veterinary viruses of uncertain pathogenic significance.

Virions are spherical, 4060 nm in diameter, and consist of a tightly adherent lipid envelope covered with indistinct spikes (peplomers) surrounding a spherical nucleocapsid.

Genome is a single molecule of linear, positive-sense, single-stranded RNA, infectious.

Cytoplasmic replication; have eight or nine nonstructural proteins and three or four structural proteins.

Maturation occurs on intracytoplasmic membranes without budding.

… FLA

VIV

IRID

AE

… FLA

VIV

IRID

AE

PICORNAVIRIDAE

Virions appear smooth and round in outline, are nonenveloped, ,30 nm in diameter, and have icosahedral symmetry.

The genome consists of a single molecule of linear, positivesense, single-stranded RNA, 78.8 kb in size, infectious.

Virion RNA acts as mRNA and is translated into a polyprotein (s) cleaved to yield some 11 or 12 individual proteins.

Cytoplasmic replication.

… PICORNAVIRIDAE

CALICIVIRUS

Virions are nonenveloped, 2740 nm in diameter, with icosahedral symmetry.

Some virions have a characteristic appearance

Virions are assembled from one capsid protein.

Genome is composed of a single molecule of linear positive-sense, single-stranded RNA, 7.48.3 kb in size, infectious.

Cytoplasmic replication.

Currently five genera.

TOGAVIRIDAE

• Alphavirus, arthropod-borne viruses, and Rubivirus, rubella virus (an exclusively human pathogen).

• Virions are spherical, enveloped, 70 nm in diameter, and consist of an envelope with fine glycoprotein spikes surrounding an icosahedral nucleocapsid.

• The genome is a single molecule of linear, positive-sense, single-stranded RNA, 9.711.8 kb in size, infectious.

• The 50 two-thirds of the genome encodes nonstructural proteins; the 30 one-third encodes the structural proteins,

• Virions contain two (or three) envelope glycoproteins E1, E2, and E3, which form the spikes, and a nucleocapsidprotein, C.

• Replication occurs in the cytoplasm, and maturation occurs via budding from the plasma membrane.

REFERENCES

Amri, I,A., Qosimah, D., Nugroho, W. 2019. Pengantar Virologi Veteriner. UB Press.

MacLachlan, N.J., Dubovi, E.J. 2016. Fenner’s Veterinary Virology 5th Edition. Academic Press.