title: Breakpoints and junctional regions of intragenic deletions in the HPRT gene in human T-Cells.
abstract: DNA sequences of the deletion breakpoints of 24 human T-lymphocyte hprt gene mutations are reported. These independent deletions ranged in size from 18 to 15655 base pairs. Seven of the 21 in vivo mutations arose in normal adults, three in normal children, eight in radioimmunotherapy patients and three in platinum chemotherapy patients. One in vitro mutation was isolated after 93cGy radon exposure and two after 300cGy gamma radiation. The breakpoints were found to be non-random and a cluster of small deletions in exon 6 is reported. Ten of the mutations had 2-5bp direct repeats at the breakpoints. There was no excess of "deletion-associated" motifs over that expected by chance. Some breakpoints do occur at consensus topoisomerase II cleavage sites and the centromeric end of a Donehower sequence occurs exactly at a telomeric breakpoint. Three mutants had breakpoints at hairpins expected by the model of Glickman and Ripley.
authors.affiliation: VCC Genetics Laboratory, University of Vermont, Burlington, Vermont 05401, USA.
authors.forename: I R
authors.initials: IR
authors.lastname: Rainville
authors.forename: R J
authors.initials: RJ
authors.lastname: Albertini
authors.forename: J A
authors.initials: JA
authors.lastname: Nicklas
mesh_terms: D000328:Adult; D001483:Base Sequence; D001665:Binding Sites; D002648:Child; D002999:Clone Cells; D016384:Consensus Sequence; D017931:DNA Primers / Q000737:chemistry; D004250:DNA Topoisomerases, Type II / Q000378:metabolism; D005091:Exons; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics*; D007231:Infant, Newborn; D007438:Introns; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D017354:Point Mutation; D016133:Polymerase Chain Reaction / Q000379:methods; D017384:Sequence Deletion; D013601:T-Lymphocytes / Q000201:enzymology*
chemical_list: D017931:DNA Primers; D007041:Hypoxanthine Phosphoribosyltransferase; D004250:DNA Topoisomerases, Type II