A transgenic construct containing the coding domain of Cre recombinase, driven by a 12.4 kb fragment of the mouse villin 1 gene, and a metallothionein polyadenylation site sequence was injected into the pronuclei of fertilized C57BL/6J x SJL/J mouse eggs. Seven lines were generated. Founder line 1000 was subsequently established. (J:78815)