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

摘要

High-density mutational spectra have been established for exon 3 of the gene encoding adenine phospho- ribosyltransferase (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 tran- sitions 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.