Tcrb^tm7Slek

ES cells containing Tcrbtm1Slek, which contain a loxP site in place of the Dbeta2-Jbeta2 gene cluster, were additionally targeted to generate a TCRb allele with only a single mutated Dbeta gene segment and a wild-type Jbeta gene segment. Five of the six Jbeta1 segments (Jbeta1.2-1.6) were replaced with a loxP-flanked neomycin cassette. The neomycin resistance gene was then removed by cre-mediated recombination. In addition, the downstream Dbeta1.1 heptamer-nonamer recombination sequence motif (cacggtg-acaaaaacc) was mutated to "attttaa-ccctctctt" to disrupt Rag mediated recombination. This allele thus has a 2 kb deletion of the Dbeta2-Jbeta2 gene segment cluster, and a 1.5 kb deletion of five Jbeta1 gene segments. As a result, all TCRbeta chain genes assembled on this allele use the mutated Dbeta1 and the Jbeta1.1 gene segments. (J:143738)