Hprt1^{tm1(CAG-Tgfbr1*)Lba}

Coding sequence for a constitutively active form of murine TGFbeta receptor I was placed downstream of a CAG promoter and a loxP-STOP-loxP motif. An HA tag was included on the C-terminus end followed by the first three exons of the Hprt locus to allow for correct targeting and selection in ES cells that had a deletion of the 5' end of the Hprt locus. The knocked-in Tgfbr1 sequence encoded three missense mutations: T204D that constitutively activates the TbRI kinase and L193A/P194A , mutations that prevent binding of the TbRI inhibitor, FKBP12. Expression of the gene can only be achieved by cre-mediated removal of the floxed STOP cassette. (J:148747)