title: Utility of a C57BL/6 ES line versus 129 ES lines for targeted mutations in mice.
abstract: Inbred ES lines, though useful for generating targeted mutations in mice, are used infrequently. To appreciate the relative efficiency of inbred ES lines, a C57BL/6 ES line was compared with 129 strain ES lines for effectiveness in chimera formation leading to the establishment of targeted mutations in mice. Data from a transgenic facility spanning 7 years were collected. C57BL/6 ES cells injected into Balb/c embryos results in lower coat color chimerism than do 129 ES cells injected into C57BL/6 embryos. Combined data indicate that five independent targeted C57BL/6 clones should be injected as compared to three independent 129 clones to generate enough chimeras to effectively test for germ-line transmission. Thus, although less efficient than 129 ES lines, the C57BL/6 ES line is a relatively competent line and useful for the routine generation of targeted mutations in mice on a defined genetic background.
authors.affiliation: Department of Comparative Medicine, University of Washington, Box 357190, Seattle, WA 98195-7190, USA. cware@u.washington.edu
authors.forename: Carol B
authors.initials: CB
authors.lastname: Ware
authors.forename: La' Akea N
authors.initials: LA
authors.lastname: Siverts
authors.forename: Angelique M
authors.initials: AM
authors.lastname: Nelson
authors.forename: John F
authors.initials: JF
authors.lastname: Morton
authors.forename: Warren C
authors.initials: WC
authors.lastname: Ladiges
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques / Q000379:methods; D002478:Cells, Cultured; D002678:Chimera; D004624:Embryo Transfer; D004622:Embryo, Mammalian / Q000166:cytology; D005260:Female; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008845:Microinjections; D009154:Mutation; D013234:Stem Cells / Q000166:cytology*