title: Comparison of the molecular characteristics of lacZ transgenic mouse mutations detected by visual and positive selection.
abstract: lacZ gene mutations in the transgenic Muta Mmouse can be detected by two different selection systems. While mutant frequencies recovered by phenyl-beta-D-galactoside (P-gal) selection are comparable with those obtained using 5-bromo-4-chloro-3-indolyl beta-D-galactopyranoside (X-gal) as substrate for beta-galactosidase, there may still be differences at the molecular level in the mutations detected by these two methods. Accordingly, we have examined a spectrum of mutants recovered from the X-gal system by regrowing these mutants on the P-gal plates. All colourless X-gal mutants grew normally on the P-gal plates. However, 11 out of 53 single light blue mutants, which express partial beta-galactosidase activity, produce few or no plaques on the P-gal plates, indicating the possible loss of some mutations using the positive selection system. Further analysis of mutant phenotypes and base changes indicates that such loss is not mutation-type specific. Our data suggest that the positive selection method can detect the majority of lacZ mutations detectable by visual selection and is more efficient at detecting mutants within a reduced range of beta-galactosidase activity.
authors.affiliation: Mutagenesis Section, Environmental Health Centre, Ottawa, Ontario, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Jiao
authors.forename: G R
authors.initials: GR
authors.lastname: Douglas
authors.forename: J D
authors.initials: JD
authors.lastname: Gingerich
authors.forename: L M
authors.initials: LM
authors.lastname: Soper
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000187:drug effects; D005038:Ethylnitrosourea / Q000633:toxicity; D005697:Galactosides / Q000378:metabolism; D005821:Genetic Techniques; D007211:Indoles / Q000378:metabolism; D008099:Liver / Q000187:drug effects; D008297:Male; D051379:Mice; D008822:Mice, Transgenic / Q000235:genetics*; D009153:Mutagens / Q000633:toxicity; D009154:Mutation; D012641:Selection, Genetic; D013094:Spermatozoa / Q000187:drug effects; D019076:Transgenes; D001616:beta-Galactosidase / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism
chemical_list: D005697:Galactosides; D007211:Indoles; D009153:Mutagens; C046399:phenyl-D-galactopyranoside; D001616:beta-Galactosidase; D005038:Ethylnitrosourea; C044888:5-bromo-4-chloro-3-indolyl beta-galactoside