Hanks M, Wurst W, Anson-Cartwright L, Auerbach A B, Joyner A L
Division of Molecular and Developmental Biology, Samuel Lunenfeld Research Institute, Mt. Sinai Hospital, Toronto, Canada.
Science. 1995 Aug 4;269(5224):679-82. doi: 10.1126/science.7624797.
The related mouse Engrailed genes En-1 and En-2 are expressed from the one- and approximately five-somite stages, respectively, in a similar presumptive mid-hindbrain domain. However, mutations in En-1 and En-2 produce different phenotypes. En-1 mutant mice die at birth with a large mid-hindbrain deletion, whereas En-2 mutants are viable, with cerebellar defects. To determine whether these contrasting phenotypes reflect differences in temporal expression or biochemical activity of the En proteins, En-1 coding sequences were replaced with En-2 sequences by gene targeting. This rescued all En-1 mutant defects, demonstrating that the difference between En-1 and En-2 stems from their divergent expression patterns.
