Question

For a ssRNA- virus, explain how it Replicates its genome, and expresses its own genes.

Answer 1

Replication and expression of its own gene by negative ssRNA

A virion enters the host cell and releases its negative RNA into the cytoplasm. This virus uses its own RNA replicase known as RNA-dependent RNA polymerase (RdRp) to form positive RNA template strands through complementary base pairing.Once the positive RNA is formed it acts as mRNA, which is translated into structural capsomere proteins and viral RdRp by the host's ribosomes. Then a replicative complex is formed with RdRp: The positive strands can either function as mRNA to produce more proteins or as template to make more negative RNA strands.New viral capsids are assembled with the capsomere proteins. The negative RNA strands combine with capsids and viral RdRp to form new negative RNA virions.After assembly and maturation of nucleocapsid, the new virions exit the cell by budding or lysing through cell membrane to further infect other cells.