title: Restrictions limiting the generation of DNA double strand breaks during chromosomal V(D)J recombination.
abstract: Antigen receptor loci are composed of numerous variable (V), diversity (D), and joining (J) gene segments, each flanked by recombination signal sequences (RSSs). The V(D)J recombination reaction proceeds through RSS recognition and DNA cleavage steps making it possible for multiple DNA double strand breaks (DSBs) to be introduced at a single locus. Here we use ligation-mediated PCR to analyze DNA cleavage intermediates in thymocytes from mice with targeted RSS mutations at the endogenous TCRbeta locus. We show that DNA cleavage does not occur at individual RSSs but rather must be coordinated between RSS pairs flanking gene segments that ultimately form coding joins. Coordination of the DNA cleavage step occurs over great distances in the chromosome and favors intra- over interchromosomal recombination. Furthermore, through several restrictions imposed on the generation of both nonpaired and paired DNA DSBs, this requirement promotes antigen receptor gene integrity and genomic stability in developing lymphocytes undergoing V(D)J recombination.
authors.affiliation: Washington University School of Medicine, Department of Pathology and Immunology, St. Louis, MO 63110, USA.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Tillman
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Wooley
authors.forename: Maureen M
authors.initials: MM
authors.lastname: Hughes
authors.forename: Tara D
authors.initials: TD
authors.lastname: Wehrly
authors.forename: Wojciech
authors.initials: W
authors.lastname: Swat
authors.forename: Barry P
authors.initials: BP
authors.lastname: Sleckman
mesh_terms: D000483:Alleles; D000818:Animals; D001483:Base Sequence; D002875:Chromosomes / Q000235:genetics; D004247:DNA / Q000235:genetics* / Q000378:metabolism; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor; D051379:Mice; D008817:Mice, Mutant Strains; D011995:Recombination, Genetic
chemical_list: D004247:DNA