The Sox10 Multiple Species Conserved Sequence 4 (MCS 4) enhancer sequence located 28.5 kb upstream of the transcriptional start site was placed in front of the Fos (c-fos) minimal promoter to drive the cre open reading frame and polyadenylation sequence. The construct was injected into pronuclei of B6SJLF1 oocytes. (J:154787)