Fig. 10F: Replication of a Single-Stranded Plus RNA Viral Genome and Production of Viral mRNA by way of Reverse Transcriptase

To replicate the viral genome, reverse transcriptase enzymes (RNA-dependent DNA polymerases) copy the (+) RNA genome producing ss (-) DNA strands. DNA-dependent DNA polymerase enzymes then copy the (-) DNA strands to produce a dsDNA intermediate. DNA-dependent RNA polymerase enzymes then copy the (-) DNA strands to produce ss (+) RNA genomes.

To produce viral mRNA molecules. DNA-dependent RNA polymerase enzymes copy the (-) DNA strand into (+) viral mRNA. The (+) viral mRNA can then be transtated into viral proteins by host cell ribosomes.