Gt(ROSA)26Sor^{em1.1(CAG-ERT2/Hoxb8)Sykes}

CRISPR/cas9 genome editing is used to insert a CAG promoter followed by a loxP:STOP:loxP (LSL) followed by the ER-Hoxb8 fusion protein into the Gt(ROSA)26Sor locus. Transient transfection with cre recombinase removes the LSL and leaves a single loxP site. The ER-Hoxb8 fusion protein comprises the hormone binding domain of the human estrogen receptor alpha fused to the murine Hoxb8 sequence. In this system, the ER-Hoxb8 protein is constitutively expressed; the estrogen receptor fusion renders the protein functionally dependent on estrogen. (J:101977)