Question

Rabies has a — strand (antisense) RNA for its genome. Describe biosynthesis of this virus including genome replication and protein production.

Answer 1

Rabies virus is a bullet shaped, enveloped virus, carrying a negative sense RNA strand. It's genome has 5 proteins in the order of :

5' L -- G -- M -- P -- N 3'.

L codes for RNA polynepoly

G codes for glycoprotein.

M codes for matrix protein.

P codes for phosphoprotein.

N codes for nucleoprotein.

Infection starts with the fusion of virus envelope and the host cell membarane . The interaction happens between the G protein of rabies virus and specific host cell receptors. The virus particles are taken in via pinocytes and on being fused with endosomes membrane, the virus is released and uncoated, releasing only the core protein part in the cytoplasm.

Since it is a - sense RNA, + sense RNA needs to be made which acts as mRNA.so RNA deoendede RNA polymerase of the virus makes + strand from the - sense genome which acts as a mRNA and encodes the viral protein. The proteins then act together and again act to make and accumulated +sense RNA strand which has 2 functions : it either acts as mRNA and encodes protein or acts as a template to make - RNA strands for the progeny viruses.

On accumulation of - RNA genomes, the N, P, L protein codes the genome to make the ribunucleoprotein or RNP. Then it binds to the M protein to form a complex of RNP-M . Glycosylation of the complex happens via Golgi apparatus and this whole thing then buds off from the host Plasma membrane.