caa a22 4500 46582076X CHVBK 20180323112135.0 cr unu---uuuuu 170327e19900901xx s 000 0 eng 10.1007/BF01233197 doi (NATIONALLICENCE)springer-10.1007/BF01233197 Replication-dependent mutagenesis by 5-bromodeoxyuridine: Identification of base change and sequence effects on mutability [Elektronische Daten] [Faming Xu, Jeffrey Greenspan, Richard Davidson] The moleeular mechanism of reversion induced by 5-bromodeoxyuridine (BrdU) replication-dependent mutagenesis in mammalian cells was studied. Murine cells with single mutant copies of theE. coli gpt gene integrated chromosomally as part of a shuttle vector were mutagenized with BrdU, and GPT+ revertants were selected. Thirteen mutant cell lines (each of which had agpt gene that varied from the wild-type gene by a different GC → AT base transition in the coding region) were mutagenized, and only four were found to be effectively reverted. All revertantgpt genes that were analyzed had reverted via AT → GC base transition at the original site of mutation, thus demonstrating that replication-dependent mutagenesis by BrdU causes AT → GC transitions. The nine cell lines that were nonrevertible by BrdU replication-dependent mutagenesis could be mutated by this protocol to ouabain resistance as effectively as the four revertible lines, indicating that the nonrevertible lines were susceptible to such mutagenesis. Thus, differences among the cell lines in frequencies of HAT' revertants generated by BrdU replication-dependent mutagenesis could not be attributed to differences in general susceptibility of the lines to the mutagenic protocol. The revertible and nonrevertible lines could not be separated according to the position of the original GC → AT transition in thegpt coding region. However, there was evidence that the DNA base sequence flanking the site of mutation affected the susceptibility of that site to BrdU replication-dependent mutagenesis. For example, six of the cell lines tested hadgpt genes in which the mutant T residue was immediately adjacent on its 3′ side to an A residue, and all six were found to be nonrevertible by BrdU replication-dependent mutagenesis. Furthermore, a target AT base pair flanked by GC base pairs in opposite orientation and either immediately adjacent to or one base removed from the target site on both the 5′ and 3′ sides appeared to have an increased susceptibility to BrdU replication-dependent mutagenesis. Plenum Publishing Corporation, 1990 Xu Faming Department of Genetics, University of Illinois College of Medicine, 808 S. Wood St., 60612, Chicago, Illinois aut Greenspan Jeffrey Department of Genetics, University of Illinois College of Medicine, 808 S. Wood St., 60612, Chicago, Illinois aut Davidson Richard Department of Genetics, University of Illinois College of Medicine, 808 S. Wood St., 60612, Chicago, Illinois aut Somatic Cell and Molecular Genetics Kluwer Academic Publishers-Plenum Publishers 16/5(1990-09-01), 477-486 0740-7750 16:5<477 1990 16 11188 https://doi.org/10.1007/BF01233197 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01233197 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Xu Faming Department of Genetics, University of Illinois College of Medicine, 808 S. Wood St., 60612, Chicago, Illinois aut NATIONALLICENCE 700 1- Greenspan Jeffrey Department of Genetics, University of Illinois College of Medicine, 808 S. Wood St., 60612, Chicago, Illinois aut NATIONALLICENCE 700 1- Davidson Richard Department of Genetics, University of Illinois College of Medicine, 808 S. Wood St., 60612, Chicago, Illinois aut NATIONALLICENCE 773 0- Somatic Cell and Molecular Genetics Kluwer Academic Publishers-Plenum Publishers 16/5(1990-09-01), 477-486 0740-7750 16:5<477 1990 16 11188 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer