The mouse alpha myosin heavy chain promoter drives the expression of a mutant Gnaq with the Q209L mutation fused to a mutant hormone-binding domain of the murine estrogen receptor in which replacement of glycine by arginine at amino acid position 525 renders the fusion proteins activity inducible by 4-hydroxytamoxifen, but unresponsive to natural estrogen. Three lines, 5, 7, and 11, were established. Line 7 is the high-expressing line. (J:104100)