The BET family of proteins targets moloney murine leukemia virus integration near transcription start sites

Cell Rep. 2013 Nov 27;5(4):886-94. doi: 10.1016/j.celrep.2013.09.040. Epub 2013 Oct 31.

Abstract

A hallmark of retroviral replication is integration of the viral genome into host cell DNA. This characteristic makes retrovirus-based vectors attractive delivery vehicles for gene therapy. However, adverse events in gene therapeutic trials, caused by activation of proto-oncogenes due to murine leukemia virus (MLV)-derived vector integration, hamper their application. Here, we show that bromodomain and extraterminal (BET) proteins (BRD2, BRD3, and BRD4) and MLV integrase specifically interact and colocalize within the nucleus of the cell. Inhibition of the BET proteins' chromatin interaction via specific bromodomain inhibitors blocks MLV virus replication at the integration step. MLV integration site distribution parallels the chromatin binding profile of BET proteins, and expression of an artificial fusion protein of the BET integrase binding domain with the chromatin interaction domain of the lentiviral targeting factor LEDGF/p75 retargets MLV integration away from transcription start sites and into the body of actively transcribed genes, conforming to the HIV integration pattern. Together, these data validate BET proteins as MLV integration targeting factors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells
  • Amino Acid Sequence
  • Animals
  • Azepines / pharmacology
  • Cell Line
  • Chromosomal Proteins, Non-Histone
  • DNA, Viral / genetics
  • Intercellular Signaling Peptides and Proteins / genetics
  • Intercellular Signaling Peptides and Proteins / metabolism
  • Leukemia Virus, Murine / genetics*
  • Mice
  • Molecular Sequence Data
  • Nuclear Proteins / antagonists & inhibitors
  • Nuclear Proteins / genetics*
  • Protein Structure, Tertiary
  • Protein-Serine-Threonine Kinases / antagonists & inhibitors
  • Protein-Serine-Threonine Kinases / genetics*
  • Transcription Factors / antagonists & inhibitors
  • Transcription Factors / genetics*
  • Transcription Initiation Site*
  • Triazoles / pharmacology
  • Virus Integration / genetics*
  • Virus Replication / drug effects
  • Virus Replication / genetics

Substances

  • (+)-JQ1 compound
  • Azepines
  • Brd2 protein, mouse
  • Brd3 protein, mouse
  • Brd4 protein, mouse
  • Chromosomal Proteins, Non-Histone
  • DNA, Viral
  • Intercellular Signaling Peptides and Proteins
  • Nuclear Proteins
  • Transcription Factors
  • Triazoles
  • lens epithelium-derived growth factor
  • Protein-Serine-Threonine Kinases