TALEN Knockout of the PSIP1 Gene in Human Cells: Analyses of HIV-1 Replication and Allosteric Integrase Inhibitor Mechanism

A Critical Role of the C-terminal Segment for Allosteric Inhibitor-induced Aberrant Multimerization of HIV-1 Integrase

“…When added to target cells, ALLINIs block 3Ј-processing as well as reduce LEDGF/p75-mediated integration into active transcription units (39,46). Knockdown or knock-out of endogenous LEDGF/p75 significantly enhanced the potencies of these inhibitors in target cells, suggesting that there is competition between the cellular protein and ALLINIs for binding to HIV-1 IN during early steps of viral replication (12,47,48). However, the ALLINI antiviral potency is determined primarily through inhibiting the late stage of HIV-1 replication (12,41,42,44,45,48).…”

“…Knockdown or knock-out of endogenous LEDGF/p75 significantly enhanced the potencies of these inhibitors in target cells, suggesting that there is competition between the cellular protein and ALLINIs for binding to HIV-1 IN during early steps of viral replication (12,47,48). However, the ALLINI antiviral potency is determined primarily through inhibiting the late stage of HIV-1 replication (12,41,42,44,45,48). In producer cells, ALLINIs potently promote aberrant, higher-order multimerization of IN during virus maturation resulting in eccentric, non-infectious cores reminiscent to the phenotype seen with some class II IN mutants (8 -12, 44, 45).…”

“…In producer cells, ALLINIs potently promote aberrant, higher-order multimerization of IN during virus maturation resulting in eccentric, non-infectious cores reminiscent to the phenotype seen with some class II IN mutants (8 -12, 44, 45). In contrast with target cells, the absence of LEDGF/p75 had no effect on ALLINI potencies in the virus producer cells (12,44,47,48). The recent discovery of pyridine-based multimerization selective IN inhibitors, which potently promoted aberrant IN multimerization in vitro and in infected cells but were not effective inhibitors of IN-LEDGF/p75 interactions, have further highlighted IN multimerization as a plausible antiviral target (46).…”

Distribution and Redistribution of HIV-1 Nucleocapsid Protein in Immature, Mature, and Integrase-Inhibited Virions: a Role for Integrase in Maturation

“…Inhibition of the LEDGF/p75-IN interaction was initially thought to underlie the mode of ALLINI action (13). However, the compounds were since discovered to affect the late stage of HIV-1 replication in a manner that is independent of LEDGF/p75 expression (12,15,18,21,22). The compounds are also active during the early stage of HIV-1 replication, but much higher concentrations are required to achieve potencies similar to those when virus producer cells are treated (12,14,15,17,18,21,22).…”

Novel Prospective Treatment Options

“…Apart from their role in enhancing resilience to HIV infection, techniques of genetic manipulation are also useful in conferring resistance to viral integration and thereby restricting the reservoir formation [155]. Although the techniques of genetic manipulation has numerous setbacks; poor frequency of recombination faced with gene therapy, unwanted off-target effects and double strand break induced apoptosis occurring with gene editing are the principal challenges that have to be overcome.…”