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In vivo loss of heterozygosity in T‐cells of B6C3F1 Aprt +/− mice
Author(s) -
Liang Li,
Deng Li,
Shao Changshun,
Stambrook Peter J.,
Tischfield Jay A.
Publication year - 2000
Publication title -
environmental and molecular mutagenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 87
eISSN - 1098-2280
pISSN - 0893-6692
DOI - 10.1002/(sici)1098-2280(2000)35:2<150::aid-em10>3.0.co;2-0
Subject(s) - adenine phosphoribosyltransferase , loss of heterozygosity , mutagen , mitotic crossover , microbiology and biotechnology , in vivo , biology , mutagenesis , mutation , chromosome , genetics , allele , carcinogen , biochemistry , enzyme , gene , purine
We have used B6C3F1 mice heterozygous at Aprt (adenine phosphoribosyltransferase) as a model to study in vivo loss of heterozygosity (LOH) in normal splenic T‐lymphocytes. APRT‐deficient T‐cells were selected in medium containing 50 μg/ml 2,6‐diaminopurine (DAP), an adenine analog that is toxic only to cells with APRT enzyme activity. DAP‐resistant (DAP r ) T‐cell variants were recovered at an average frequency of 3 × 10 −5 from 21 B6C3F1 Aprt +/− mice. Allele‐specific PCR of Aprt showed that about 70% of 122 DAP r colonies were caused by loss of the nontargeted Aprt allele ( Aprt + ). Analysis of microsatellite markers along the length of chromosome 8 suggested that mitotic recombination, or chromosome loss, with or without duplication of the remaining chromosome are the predominant mechanisms resulting in loss of Aprt + . DNA sequencing of Aprt RT‐PCR products from the DAP r variants that retained Aprt + indicated that point mutation as well as other mechanisms could cause this second class of variants. The high spontaneous frequency of in vivo Aprt LOH in mouse T‐cells, mediated by LOH mechanisms that are also known to produce human cancers, suggests that the Aprt heterozygous mouse is a valid model for studying the diversity of mechanisms for in vivo somatic mutagenesis. Environ. Mol. Mutagen. 35:150–157, 2000 © 2000 Wiley‐Liss, Inc.