The Cleavage and Polyadenylation Specificity Factor 6 (CPSF6) Subunit of the Capsid-recruited Pre-messenger RNA Cleavage Factor I (CFIm) Complex Mediates HIV-1 Integration into Genes

J Biol Chem. 2016 May 27;291(22):11809-19. doi: 10.1074/jbc.M116.721647. Epub 2016 Mar 18.

Abstract

HIV-1 favors integration into active genes and gene-enriched regions of host cell chromosomes, thus maximizing the probability of provirus expression immediately after integration. This requires cleavage and polyadenylation specificity factor 6 (CPSF6), a cellular protein involved in pre-mRNA 3' end processing that binds HIV-1 capsid and connects HIV-1 preintegration complexes to intranuclear trafficking pathways that link integration to transcriptionally active chromatin. CPSF6 together with CPSF5 and CPSF7 are known subunits of the cleavage factor I (CFIm) 3' end processing complex; however, CPSF6 could participate in additional protein complexes. The molecular mechanisms underpinning the role of CPSF6 in HIV-1 infection remain to be defined. Here, we show that a majority of cellular CPSF6 is incorporated into the CFIm complex. HIV-1 capsid recruits CFIm in a CPSF6-dependent manner, which suggests that the CFIm complex mediates the known effects of CPSF6 in HIV-1 infection. To dissect the roles of CPSF6 and other CFIm complex subunits in HIV-1 infection, we analyzed virologic and integration site targeting properties of a CPSF6 variant with mutations that prevent its incorporation into CFIm We show, somewhat surprisingly, that CPSF6 incorporation into CFIm is not required for its ability to direct preferential HIV-1 integration into genes. The CPSF5 and CPSF7 subunits appear to have only a minor, if any, role in this process even though they appear to facilitate CPSF6 binding to capsid. Thus, CPSF6 alone controls the key molecular interactions that specify HIV-1 preintegration complex trafficking to active chromatin.

Keywords: CFIm; CPSF6; RNA processing; capsid; human immunodeficiency virus (HIV); infection; integration; nuclear transport; protein complex.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Capsid / metabolism*
  • HIV Infections / genetics
  • HIV Infections / metabolism
  • HIV Infections / virology
  • HIV-1 / genetics
  • HIV-1 / physiology*
  • Humans
  • RNA Precursors / genetics
  • RNA Precursors / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism*
  • Virus Integration*
  • mRNA Cleavage and Polyadenylation Factors / chemistry
  • mRNA Cleavage and Polyadenylation Factors / genetics
  • mRNA Cleavage and Polyadenylation Factors / metabolism*

Substances

  • RNA Precursors
  • RNA, Messenger
  • cleavage factor Im, human
  • mRNA Cleavage and Polyadenylation Factors