title: Repair of chromosomal RAG-mediated DNA breaks by mutant RAG proteins lacking phosphatidylinositol 3-like kinase consensus phosphorylation sites.
abstract: Ataxia telangiectasia mutated (ATM) and DNA-dependent protein kinase catalytic subunits (DNA-PKcs) are members of the phosphatidylinositol 3-like family of serine/threonine kinases that phosphorylate serines or threonines when positioned adjacent to a glutamine residue (SQ/TQ). Both kinases are activated rapidly by DNA double-strand breaks (DSBs) and regulate the function of proteins involved in DNA damage responses. In developing lymphocytes, DSBs are generated during V(D)J recombination, which is required to assemble the second exon of all Ag receptor genes. This reaction is initiated through a DNA cleavage step by the RAG1 and RAG2 proteins, which together comprise an endonuclease that generates DSBs at the border of two recombining gene segments and their flanking recombination signals. This DNA cleavage step is followed by a joining step, during which pairs of DNA coding and signal ends are ligated to form a coding joint and a signal joint, respectively. ATM and DNA-PKcs are integrally involved in the repair of both signal and coding ends, but the targets of these kinases involved in the repair process have not been fully elucidated. In this regard, the RAG1 and RAG2 proteins, which each have several SQ/TQ motifs, have been implicated in the repair of RAG-mediated DSBs. In this study, we use a previously developed approach for studying chromosomal V(D)J recombination that has been modified to allow for the analysis of RAG1 and RAG2 function. We show that phosphorylation of RAG1 or RAG2 by ATM or DNA-PKcs at SQ/TQ consensus sites is dispensable for the joining step of V(D)J recombination.
authors: Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors: Eric J
authors: EJ
authors: Gapud
authors: Baeck-Seung
authors: BS
authors: Lee
authors: Grace K
authors: GK
authors: Mahowald
authors: Craig H
authors: CH
authors: Bassing
authors: Barry P
authors: BP
authors: Sleckman
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D002461:Cell Line, Transformed; D019457:Chromosome Breakage; D033481:Chromosomes, Mammalian / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D055261:Immunogenetic Phenomena / Q000502:physiology; D008214:Lymphocytes / Q000276:immunology / Q000378:metabolism; D051379:Mice; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D010766:Phosphorylation / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D011995:Recombination, Genetic / Q000502:physiology*; D017384:Sequence Deletion; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism
chemical_list: D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D025521:Tumor Suppressor Proteins; C499308:Rag2 protein, mouse; C064658:RAG-1 protein; C576325:Atm protein, mouse