Association of integrase, matrix, and reverse transcriptase antigens of human immunodeficiency virus type 1 with viral nucleic acids following acute infection.

Abstract

We have examined components of the preintegration complex of human immunodeficiency virus type 1 (H1V-1) and have analyzed features which govern the association of these components. HIV-1 nucleoprotein complexes, isolated from nuclear and cytoplasmic extracts of CD4+ cells after acute virus infection, contained viral RNA and DNA in association with viral matrix (MA), integrase (IN), and reverse ranscriptase (RT) antigens but not capsid (CA) antigens and posessed integration activity in vitro. Association of IN but not RT or MA antigens with viral DNA was detergent-stable. Analysis of viral DNA synthesis and nuclear import of viral nucleoprotein complexes in the presence of a reversible RT inhibitor demonstrated that reverse transcription of viral RNA could be completed entirely in the host cell nucleus. Our studies demonstrate structural and functional features of the nudeoprotein (preintegration) complex of HIV-1 which are pertinent to the understanding of early events in the lentiviral life cycle.

Integrase, LEDGF/p75 and HIV replication

“…The PIC is a macromolecular assemblage that consists of the viral cDNA, a subset of viral proteins retained from the initial reverse transcription complex, and probably host cell proteins [5,[15][16][17][18][19]. Similarly, chromatin is compositionally and structurally intricate.…”

Intracellular trafficking of retroviral vectors: obstacles and advances

“…Where uncoating occurs in the cytoplasm is controversial. While some believe the viral CA immediately disassembles from the core after entry into the cytoplasm based on purified RTC/PIC preparations, [41][42][43] others have evidence that the CA shell persists longer in the cytoplasm 26,44 (see below). Furthermore, the role of reverse transcription in uncoating remains unclear.…”

“…26,[41][42][43] However, reports that MA phosphorylation regulates late reverse transcript production 48,49 and NC chaperones reverse transcription (reviewed elsewhere 50 ) suggests MA and NC stay with HIV RTCs for atleast part of their cytoplasmic journey to impart their effects on reverse transcription. Along with the viral RT and IN enzymes, specialized viral proteins like the Vpr and Nef accessory proteins also remain with HIV-1 cores deposited in the cytoplasm.…”

“…26 Both RTC types contained the HIV-1 MA protein (p17 MA ) consistent with some biochemical studies. 41,43 While the p24 CA -positive RTCs may represent defective complexes incapable of further infection, it is equally possible these p24 CApositive and -negative RTCs represent an early and later step in RTC maturation enroute to the nucleus. Recent work investigating HIV-1 restriction in owl monkey cells supports the notion early p24 CA HIV-1 RTCs exist in the cytoplasm.…”

“…26,[41][42][43] Therefore, how might CA promote nuclear import if it has already been shed from the PIC? It is possible HIV-1 CA may direct viral RTCs on a cytoplasmic pathway before being shed that leads to efficient NPC trafficking.…”