title: Structure-based mutagenesis of the integrase-LEDGF/p75 interface uncouples a strict correlation between in vitro protein binding and HIV-1 fitness.
abstract: LEDGF/p75 binding-defective IN mutant viruses were previously characterized as replication-defective, yet RNAi did not reveal an essential role for the host factor in HIV-1 replication. Correlative analyses of protein binding and viral fitness were expanded here by targeting 12 residues at the IN-LEDGF/p75 binding interface. Whereas many of the resultant viruses were defective, the majority of the INs displayed wild-type in vitro integration activities. Though an overall trend of parallel loss of LEDGF/p75 binding and HIV-1 infectivity was observed, a strict correlation was not. His-tagged IN(A128Q), derived from a phenotypically wild-type virus, failed to pull-down LEDGF/p75, but IN(A128Q) was effectively recovered in a reciprocal GST pull-down assay. Under these conditions, IN(H171A), also derived from a phenotypically wild-type virus, interacted less efficiently than a previously described interaction-defective mutant, IN(Q168A). Thus, the relative affinity of the in vitro IN-LEDGF/p75 interaction is not a universal predictor of IN mutant viral fitness.
authors.affiliation: Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
authors.forename: Shaila
authors.initials: S
authors.lastname: Rahman
authors.forename: Richard
authors.initials: R
authors.lastname: Lu
authors.forename: Nick
authors.initials: N
authors.lastname: Vandegraaff
authors.forename: Peter
authors.initials: P
authors.lastname: Cherepanov
authors.forename: Alan
authors.initials: A
authors.lastname: Engelman
mesh_terms: D002460:Cell Line; D015658:HIV Infections / Q000821:virology; D019427:HIV Integrase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000378:metabolism / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D019169:Jurkat Cells; D008958:Models, Molecular; D016296:Mutagenesis; D011485:Protein Binding; D016662:Virus Integration
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; C119380:lens epithelium-derived growth factor; D019427:HIV Integrase