Retroviral intasomes search for a target DNA by 1D diffusion which rarely results in integration

Nat Commun. 2016 Apr 25:7:11409. doi: 10.1038/ncomms11409.

Abstract

Retroviruses must integrate their linear viral cDNA into the host genome for a productive infection. Integration is catalysed by the retrovirus-encoded integrase (IN), which forms a tetramer or octamer complex with the viral cDNA long terminal repeat (LTR) ends termed an intasome. IN removes two 3'-nucleotides from both LTR ends and catalyses strand transfer of the recessed 3'-hydroxyls into the target DNA separated by 4-6 bp. Host DNA repair restores the resulting 5'-Flap and single-stranded DNA (ssDNA) gap. Here we have used multiple single molecule imaging tools to determine that the prototype foamy virus (PFV) retroviral intasome searches for an integration site by one-dimensional (1D) rotation-coupled diffusion along DNA. Once a target site is identified, the time between PFV strand transfer events is 470 ms. The majority of PFV intasome search events were non-productive. These observations identify new dynamic IN functions and suggest that target site-selection limits retroviral integration.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • DNA / chemistry
  • DNA / genetics*
  • DNA / metabolism
  • DNA, Single-Stranded / chemistry
  • DNA, Single-Stranded / genetics
  • DNA, Single-Stranded / metabolism
  • Diffusion
  • Gene Expression
  • Humans
  • Integrases / chemistry
  • Integrases / genetics*
  • Integrases / metabolism
  • Single Molecule Imaging / methods
  • Spumavirus / genetics*
  • Spumavirus / metabolism
  • Terminal Repeat Sequences
  • Time-Lapse Imaging / methods
  • Viral Proteins / chemistry
  • Viral Proteins / genetics*
  • Viral Proteins / metabolism
  • Virus Integration*

Substances

  • DNA, Single-Stranded
  • Viral Proteins
  • DNA
  • Integrases