Tcra-J^tm1Slek

Using ES cells with a single loxP site 5' of the endogenous TEA promoter, a targeting vector was used to insert a floxed neo, TEA promoter, TEA exon, Jalpha61 and Jalpha56 sequences downstream of the Jalpha region. Resultant ES cells were transfected with cre recombinase, leading to the 66-kb deletion between the loxP sites 5' of the TAE endogenous promoter and 3' of the neomycin resistant gene. Only the Jalpha56 could give rise to a functional Jalpha arrangement in mutant mice. These mice have increased thymocyytes but reduced mature alphabeta T cell numbers. (J:101398)