SJP-L-5 inhibits HIV-1 polypurine tract primed plus-strand DNA elongation, indicating viral DNA synthesis initiation at multiple sites under drug pressure

In a previous study the small molecule SJP-L-5 that inhibits HIV replication, has been shown to block uncoating of the viral capsid. Continued study showed that SJP-L-5 might hinder HIV capsid uncoating by blocking the completion of reverse transcription. However, to date, the mechanism has not been fully elucidated. Here, the effects of SJP-L-5 for reverse transcription were explored via quantitative PCR, DIG-labelled ELISA, fluorescent resonance energy transfer, and Southern blot assays. We also analyzed the resistance profile of this compound against reverse transcriptase. Our results show that SJP-L-5 preferentially inhibits PPT primed plus-strand DNA synthesis (EC(50) = 13.4 ± 3.0 μM) over RNA primed minus-strand DNA synthesis (EC(50) > 3,646 μM), resulting in formation of five segmented plus-strand DNA and loss of HIV DNA flap, suggesting failure of both nuclear import and integration. Moreover, resistance study evidenced that SJP-L-5 requires the amino acid residues Val108 and Tyr181 to exert an inhibitory effect. These results indicate SJP-L-5 as a new non-nucleoside reverse transcriptase inhibitor that inhibits HIV-1 polypurine tract primed plus-strand DNA synthesis, initiating HIV-1 down-stream plus-strand DNA synthesis at multiple sites under drug pressure.