Isolation and characterization of an oligomerization-negative mutant of HIV-1 integrase

The yeast two-hybrid method was used to screen mutagenized DNAs to isolate a variant of the human immunodeficiency virus type 1 integrase (IN) that do es not interact with the wild-type IN. The responsible mutation, leading to a single amino acid change (V260E) in the C-terminal domain of IN, blocks IN-IN multimerization but has only small effect on binding to a host intera cting protein, INI1 (hSNF5). Binding studies in vitro confirmed the defect in multimerization of the mutant IN. Biochemical analyses of the mutant IN enzyme expressed in bacteria detected only subtle changes in its properties , suggesting that the yeast system is a sensitive reporter of correct IN co nformation. Mutant virus carrying the V260E substitution was blocked in rep lication at the time of DNA integration, consistent with IN multimerization being important for its activity in vivo. (C) 1999 Academic Press.