Role of poly(ADP-ribosyl)ation in DNA-PKcs- independent V(D)J recombination.
V(D)J recombination is critical to the generation of a functional immune system. Intrinsic to the assembly of antigen receptor genes is the formation of endogenous DNA double-strand breaks, which normally are excluded from the cellular surveillance machinery because of their sequestration in a synaptic complex and/or rapid resolution. In cells deficient in double-strand break repair, such recombination-induced breaks fail to be joined promptly and therefore are at risk of being recognized as DNA damage. Poly(ADP-ribose) polymerase-1 is an important factor in the maintenance of genomic integrity and is believed to play a central role in DNA repair. Here we provide visual evidence that in a recombination inducible severe combined immunodeficient cell line poly(ADP-ribose) formation occurs during the resolution stage of V(D)J recombination where nascent opened coding ends are generated. Poly(ADP-ribose) formation appears to facilitate coding end resolution. Furthermore, formation of Mre11 foci coincide with these areas of poly(ADP-ribosyl)ation. In contrast, such a response is not observed in wild-type cells possessing a functional catalytic subunit of DNA-dependent protein kinase (DNA-PK(cs)). Thus, V(D)J recombination invokes a DNA damage response in cells lacking DNA-PK(cs) activity, which in turn promotes DNA-PK(cs)-independent resolution of recombination intermediates.
Brown
Matthew L
ML
Department of Microbiology, Molecular and Cellular Biology Program, Arizona State University, Tempe, AZ 85287-2701, USA.
Franco
Daniel
D
Burkle
Alexander
A
Chang
Yung
Y
D000818:Animals; D002874:Chromosome Mapping; D004249:DNA Damage; D051747:DNA-Activated Protein Kinase; D004268:DNA-Binding Proteins; D004789:Enzyme Activation; D005568:Forms and Records Control; D007133:Immunoglobulin Joining Region / Q000235:genetics*; D007135:Immunoglobulin Variable Region / Q000235:genetics*; D051379:Mice; D016513:Mice, SCID; D011064:Poly Adenosine Diphosphate Ribose / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D011995:Recombination, Genetic
D004268:DNA-Binding Proteins; D007133:Immunoglobulin Joining Region; D007135:Immunoglobulin Variable Region; D011064:Poly Adenosine Diphosphate Ribose; D011065:Poly(ADP-ribose) Polymerases; D051747:DNA-Activated Protein Kinase; D017346:Protein Serine-Threonine Kinases