541. Increased Integration of Lentiviral Vector Carrying a D167H Integrase Relies on the Presence of LEDGF/p75

Abstract

HIV-1 vectors derive from a virus specialized of host human cells whose replication relies on a dynamic interplay between viral and cellular proteins. Critical for HIV-1 replication is the integration of its genome in the host cellular chromatin, a feature exploited by lentiviral vectors to ensure persistent transgene expression across generations in proliferating cells. To reach to that point the RNA genome of HIV must first ensure its reverse transcription as it is transported to the nucleus. During this early step of transduction the vector particle undergoes successive structural transformation from the reverse transcription complex (RTC), where the vector DNA is synthesized, to the preintegration complex (PIC) which is an assembly of vector and cellular factors able to catalyze vector genome integration into cellular DNA. The viral protein integrase (IN), in addition to catalyze viral DNA integration, also participates in the structure and function of these dynamic complexes through timely interactions with itself and with other viral and cellular proteins. We have previously shown that a HIV vector carrying a mutant integrase (D167H) had improved integration capabilities as compared to particles with wild type integrase. Here we show that such improvement is dependent on the presence of the cellular factor LEDGF/p75 and that this protein is required at integration step but is dispensable for nuclear translocation of the PIC.