Retroviruses

[eagle]

Reverse transcriptases do not proofread as they synthesize DNA using an RNA template.What are the consequences of this for the treatment of AIDS?

[eagle]

Another related Q.
What would you expect to happen to mRNA's if animal cells contained high levels of reverse transcriptase in their cytoplasm?

[eagle]

To Q 1)Since the AIDS virus is a retrovirus using reverse transcriptase to synthesise DNA from an RNA template- there are frequent mutations of the viral genome.In fact, AIDS patients often harbourmany different variants of HIV that are genetically distinct from the original virus that infected them.
So problems arise: drugs that block essential enzymes work only temporarily since new virus strains arise by mutation.
Cool huh?

[eagle]

To Q 2) mRNAs could be converted back to DNA sequences.These DNA sequences would differ because
a) they would contain mutations (reverse transcriptase does not proof read)
b) they would not contain introns, and maybe lack certain promoter sequences.
This defective DNA could rejoin the previous or another chromosome by recombination - but may never be effective for protein synthesis.
Moreover, the high levels of mutations would eventually put the species at a risk.