Promoter traps in embryonic stem cells: a genetic screen to identify and mutate developmental genes in mice.
A general strategy for selecting insertion mutations in mice has been devised. Constructs lacking a promoter and including a beta-galactosidase gene, or a reporter gene encoding a protein with both beta-galactosidase and neomycin phosphotransferase activity, were designed so that activation of the reporter gene depends on its insertion within an active transcription unit. Such insertion events create a mutation in the tagged gene and allow its expression to be followed by beta-galactosidase activity. Introduction of promoter trap constructs into embryonic stem (ES) cells by electroporation or retroviral infection has led to the derivation of transgenic lines that show a variety of beta-galactosidase expression patterns. Intercrossing of heterozygotes from 24 strains that express beta-galactosidase identified 9 strains in which homozygosity leads to an embryonic lethality. Because no overt phenotype was detected in the remaining strains, these results suggest that a substantial proportion of mammalian genes identified by this approach are not essential for development.
Friedrich
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G
Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas 77030.
Soriano
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P
D000818:Animals; D015152:Blotting, Northern; D015139:Blotting, Southern; D002460:Cell Line; D003001:Cloning, Molecular; D005333:Fetus; D005822:Genetic Vectors; D005854:Germ Cells; D019868:Kanamycin Kinase; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008822:Mice, Transgenic; D016254:Mutagenesis, Insertional / Q000235:genetics*; D010641:Phenotype; D010770:Phosphotransferases / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D013234:Stem Cells; D001616:beta-Galactosidase / Q000235:genetics* / Q000378:metabolism
D010770:Phosphotransferases; D019868:Kanamycin Kinase; D001616:beta-Galactosidase