Replication Strategy of ss(+)RNA Viruses Replicating via a Longer-Than-Genome-Length DNA Intermediate

Note: look at status bar when mouse is over numbers in picture for explanations of steps

Note: this is an animated GIF, which takes about 30 sec to cycle through completely.

Steps in Replication

1. Reverse transcription in cytoplasm, using tRNA primer, of virion ss(+)RNA by virion-associated reverse transcriptase (RT), into intermediate RNA/DNA complex

2. Conversion of RNA/DNA complex into linear and circular proviral dsDNA forms with long terminal repeats (LTRs) by RT; import into nucleus

3. Integration of linear proviral DNA into host cell DNA, by means of integrase function of RT

4. Replication and trasncription as for host DNA, using host enzymes

5. Modification of transcription by (early) viral products (bias to production of genome-length (+)sense RNA?)

6. Translation, accumulation of (late) structural protein, assembly with (+)sense genomic RNA into viral nucleoprotein, budding through membrane containing viral envelope (glyco)proteins