Hesx1^tm3Jpmb

The coding sequence for wild-type Hesx1 was mutated by PCR so that codon 160 (arginine) was changed to encode a cysteine residue (CGA->TGC). A loxP-flanked PGK-Neo selection cassette was inserted into the first intron of the mutated Hesx1 sequence in the targeting vector. The orientation of the PGK-Neo was inverted relative to the normal direction of transcription in an attempt to reduce expression of the mutated allele, which may have a dominant negative effect in ES cells where the Hesx1 locus is transcripitionally active. Homologous recombination in CCE ES cells replaced the wild-type sequence with the mutant sequence in the targeting vector. F1 animals were crossed with Actin-beta-cre mice to excise the PGK-Neo cassette. (J:142649)