Retroviral integration: Structure of the initial covalent product and its precursor, and a role for the viral IN protein Academic Article uri icon


MeSH Major

  • DNA, Viral
  • Genes, Viral
  • Leukemia Virus, Murine
  • Viral Proteins


  • An essential step in the life cycle of a retrovirus is the integration of a DNA copy of the viral genome into a host cell chromosome. We have analyzed the structure of the initial covalent product of an in vitro retroviral integration reaction and determined the structure of the ends of the unintegrated linear viral DNA molecules present in vivo in cells infected with murine leukemia virus (MLV). Our results lead to the following conclusions: (i) Circularization of viral DNA plays no role in integration. The direct precursor to the integrated MLV provirus is a linear molecule. (ii) The initial step in the integration reaction is probably a cleavage that removes the terminal 2 bases from each 3' end of the viral DNA. This cleavage depends on a virally encoded protein, IN, that has previously been shown genetically to be required for integration. (iii) The resulting viral 3' ends are joined to target DNA to form the initial recombination intermediate.

publication date

  • January 1989



  • Academic Article



  • eng

PubMed Central ID

  • PMC286949

PubMed ID

  • 2539592

Additional Document Info

start page

  • 2525

end page

  • 9


  • 86


  • 8