HIV-1 Resistance to Dolutegravir Is Affected by Cellular Histone Acetyltransferase Activity.

Integrase strand transfer inhibitors (INSTIs) are the newest class of antiretrovirals to be approved for the treatment of HIV infection. Canonical resistance to these competitive inhibitors develops through substitutions in the integrase active site that disrupt drug-protein interactions. However, resistance against the newest integrase inhibitor, dolutegravir (DTG), is associated with an R263K substitution at the C terminus of integrase that causes resistance through an unknown mechanism. The integrase C-terminal domain is involved in many processes over the course of infection and is posttranslationally modified via acetylation of three lysine residues that are important for enzyme activity, integrase multimerization, and protein-protein interactions. Here we report that regulation of the acetylation of integrase is integral to the replication of HIV in the presence of DTG and that the R263K mutation specifically disrupts this regulation, likely due to enhancement of interactions with the histone deacetylase I complex, as suggested by coimmunoprecipitation assays. Although no detectable differences in the levels of cell-free acetylation of the wild-type (WT) and mutated R263K enzymes were observed, the inhibition of cellular histone acetyltransferase enzymes sensitized the NL4.3