Creb1^tm1Jsca

A minigene consisting of wild-type exon 4 fused to the downstream exons of this gene locus was used in a targeting vector. The minigene and a neo-selection cassette were flanked with loxP sites and placed upstream of a mutated exon 4 sequence that substitutes the serine at amino acid 133 to an Alanine. This targeting vector was used to replace the endogenous exon 4 of the gene locus. In the absence of Cre expression, splicing between exon 3 and the minigene results in expression of a wild-type protein. Following expression of Cre-recombinase, the minigene is removed and splicing occurs on to the mutated exon 4 leading to transcription of the Ser133Ala mutant. (J:139576)