Loss of alleles in aprt mutants of CHO cells demonstrated by BclI restriction-fragment-length variation.
A BclI restriction-fragment-length variation (RFLV) has been identified 7 kb downstream of the 3' end of the adenine phosphoribosyltransferase (aprt) gene in the Chinese hamster CHO cell line. This RFLV generates 19 kb and 17 kb + 2 kb BclI fragments. Three other cell lines derived from different Chinese hamsters are homozygous for this RFLV. The 17 kb + 2 kb allele was mapped to the Z4 chromosome based upon the absence of this allele in the CHO-derived hemizygote AA8-5, whose functional allele is known to map to chromosome Z7. The class 2 aprt+/-line D416 loses the 19-kb allele after undergoing the high-frequency (HF) deletion event, indicating that the HF deletion event occurs on the Z7 chromosome. On the other hand, deletion events in the class 3 heterozygote D423 (which do not spontaneously occur at HF) resulted in loss of the 17 kb + 2 kb allele. This is consistent with a previously proposed model holding that the two aprt alleles in the CHO cell line have different inherent probabilities of undergoing a large deletion event.
Dewyse
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Institut du Cancer de Montréal, Sherbrooke, Québec, Canada.
Bradley
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D000228:Adenine Phosphoribosyltransferase / Q000235:genetics*; D000483:Alleles; D000818:Animals; D015139:Blotting, Southern; D002460:Cell Line; D002874:Chromosome Mapping; D002875:Chromosomes; D006224:Cricetinae; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D006579:Heterozygote; D006720:Homozygote; D009154:Mutation; D010430:Pentosyltransferases / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D015183:Restriction Mapping
D010430:Pentosyltransferases; D000228:Adenine Phosphoribosyltransferase; C041666:endodeoxyribonuclease BclI; D015252:Deoxyribonucleases, Type II Site-Specific