title: Spectrum of spontaneous HPRT- mutations in TK6 human lymphoblasts.
abstract: The occurrence of deletions, coding sequence alterations, and intronic changes leading to aberrant splicing has been characterized among 33 spontaneous HPRT- mutants in TK6 human lymphoblasts. Deletions detectable by multiplex PCR amplification accounted for 45% (15/33) of the mutant collection. Base substitutions represented 30% (10/33) of the total, and were predominated by changes at G:C base pairs. The remaining mutants were distributed among frameshifts (9%, 3/33), small deletions (6%, 2/33), and compound alterations (9%, 3/33). Five mutants (15%) demonstrated aberrant splicing of the hprt transcript. A cluster of 4 deletion/insertion events was identified in hprt exon 6. A nearly perfect 13 bp duplication differed from the original sequence only by an A:T to G:C transition, which was observed as a unique alteration in another HPRT- mutant. A model involving correction of a mismatch in a secondary structure formed by the duplicated sequence may account for these results.
authors.affiliation: Graduate Programs, University of California, Riverside 92521.
authors.forename: C R
authors.initials: CR
authors.lastname: Giver
authors.forename: S L
authors.initials: SL
authors.lastname: Nelson
authors.forename: A J
authors.initials: AJ
authors.lastname: Grosovsky
mesh_terms: D001402:B-Lymphocytes / Q000201:enzymology / Q000648:ultrastructure; D001483:Base Sequence; D002460:Cell Line; D004252:DNA Mutational Analysis; D016368:Frameshift Mutation; D017353:Gene Deletion; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics*; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009154:Mutation; D009692:Nucleic Acid Heteroduplexes; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D017384:Sequence Deletion; D013489:Suppression, Genetic
chemical_list: D009692:Nucleic Acid Heteroduplexes; D007041:Hypoxanthine Phosphoribosyltransferase