Final answer:
The "copy choice" recombination in retrovirus replication involves reverse transcriptase switching between RNA templates during cDNA synthesis, contributing to genetic diversity and the emergence of new viral strains. This process is critical for understanding the development of therapeutic strategies against retroviral diseases.
Step-by-step explanation:
“Copy choice” recombination in retrovirus replication is a process where reverse transcriptase enzyme switches between different RNA templates during the synthesis of complementary DNA (cDNA). This can happen during the reverse transcription of the retroviral RNA genome when the enzyme encounters sequences that are similar between the two RNA molecules. Such template switching allows the retrovirus to potentially mix and match genetic information, which can result in the generation of recombinant viral genomes.
Retroviruses, like HIV, contain reverse transcriptase that converts their single-stranded RNA into a double-stranded DNA form, which can then integrate into the host cell's genome, becoming a provirus. Once integrated, the proviral DNA can produce transcripts that are translated into proteins necessary for the formation of new viral particles. However, should reverse transcriptase copy RNA of a defective virus or of an endogenous retrovirus (ERV), these copied cDNAs might not form infectious particles but could behave like LTR retrotransposons and integrate into the host genome.
In summary, the “copy choice” recombination is a significant factor that contributes to the genetic diversity of retroviruses and can lead to the emergence of new viral strains with different properties. Understanding this process is critical for the development of therapeutic strategies targeting retroviral diseases.