Influence of alkyltransferase activity and chromosomal locus on mutational hotspots in Chinese hamster ovary cells

被引:5
作者
Belouchi, A [1 ]
Ouimet, M [1 ]
Dion, P [1 ]
Gaudreault, N [1 ]
Bradley, WEC [1 ]
机构
[1] UNIV MONTREAL,DEPT MED,MONTREAL,PQ H3C 3J7,CANADA
关键词
D O I
10.1073/pnas.93.1.121
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
High-density mutational spectra have been established for exon 3 of the gene encoding adenine phosphoribosyltransferase (APRT) of the Chinese hamster ovary (CHO) cell line derivative D422 and closely related and/or modified lines by using the mutagen ethyl methanesulfonate (EMS). The total number of selectable sites (GC --> AT transitions yielding a selectable APRT(-) phenotype) was estimated at 31 based on our own accumulated data base of 136 sequenced exon 3 mutations and on literature reports. D422 and two other APRT hemizygous lines each yielded very similar spectra and showed two populations of mutable sites: (i) 24 ''baseline'' sites that followed the Poisson distribution and therefore were equally susceptible to mutation and (ii) two hotspots, one comprising a cluster at nucleotides 1293-1309 and the other at nucleotide 1365. Collectively, the Latter sites were about 10-fold more frequently mutated than the others. CHO cells are mer(-) as they lack the repair enzyme O-6-methylguanidine methyltransferase (EC 2.1.1.63). In modified repair-proficient CHO cells, the distribution of mutations among all of the 31 sites was random, with only 3 of the 19 GC --> AT transitions in the above hotspots. To determine whether the distribution was locus-dependent, two independent lines carrying single copies of transfected APRT genes were generated from a derivative of D422 carrying a deletion in the endogenous APRT gene. Nucleotides 1293-1309 were again no longer preferentially mutated, but the site at nucleotide 1365 was still a hotspot. We conclude that mutational spectra in mer(-) cells are at least in part locus dependent and that some sequences are particularly susceptible to EMS mutagenesis and perhaps also to methyltransferase repair.
引用
收藏
页码:121 / 125
页数:5
相关论文
共 37 条
[1]  
AQUILINA G, 1992, CANCER RES, V52, P6471
[2]  
ASHMAN CR, 1992, MUTAT RES, V2370, P115
[3]   DNA-REPAIR IN THE C-MYC PROTOONCOGENE LOCUS - POSSIBLE INVOLVEMENT IN SUSCEPTIBILITY OR RESISTANCE TO PLASMACYTOMA INDUCTION IN BALB/C MICE [J].
BEECHAM, EJ ;
MUSHINSKI, JF ;
SHACTER, E ;
POTTER, M ;
BOHR, VA .
MOLECULAR AND CELLULAR BIOLOGY, 1991, 11 (06) :3095-3104
[4]   ANALYSIS OF 2ND-STEP MUTATIONS OF CLASS-II AND CLASS-III CHO APRT HETEROZYGOTES - CHROMOSOMAL DIFFERENCES IN DELETION FREQUENCIES [J].
BELOUCHI, A ;
BRADLEY, WEC .
SOMATIC CELL AND MOLECULAR GENETICS, 1991, 17 (03) :277-286
[5]   A MUTATIONAL HOTSPOT IN THE APRT GENE OF CHINESE-HAMSTER CELLS [J].
BELOUCHI, A ;
BRADLEY, WEC .
MUTATION RESEARCH, 1992, 266 (02) :221-230
[6]   HIGH-FREQUENCY NONRANDOM MUTATIONAL EVENT AT THE ADENINE PHOSPHORIBOSYLTRANSFERASE (APRT) LOCUS OF SIB-SELECTED CHO VARIANTS HETEROZYGOUS FOR APRT [J].
BRADLEY, WEC ;
LETOVANEC, D .
SOMATIC CELL GENETICS, 1982, 8 (01) :51-66
[7]   LOW PERSISTENCE OF THE INDUCED MUTANT PHENOTYPE IN CHINESE-HAMSTER CELLS [J].
BRADLEY, WEC ;
LAVIOLETTE, F .
MUTATION RESEARCH, 1989, 210 (02) :303-311
[8]  
BRONSTEIN SM, 1991, CANCER RES, V51, P5188
[9]   INFLUENCE OF NEIGHBORING BASE SEQUENCE ON N-METHYL-N'-NITRO-N-NITROSOGUANIDINE MUTAGENESIS IN THE LACI GENE OF ESCHERICHIA-COLI [J].
BURNS, PA ;
GORDON, AJE ;
GLICKMAN, BW .
JOURNAL OF MOLECULAR BIOLOGY, 1987, 194 (03) :385-390
[10]   MUTATIONS AFFECTING ADENINE PHOSPHORIBOSYL TRANSFERASE-ACTIVITY IN CHINESE-HAMSTER CELLS [J].
CHASIN, LA .
CELL, 1974, 2 (01) :37-41