The H3K27ac regulatory (enhancer) element of the embryonic external genitalia (eExG) enhancer in the 3' UTR of Mafb was targeted with gRNAs (targeting TCTGTGAGTCCTGGCGGGTCCGG and TGCCGAGATCCACATCGTGCA) using CRISPR/Cas9 technology, resulting in a 1068 bp deletion. (J:306453)