Exons 4-10 were replaced by an IRES-lacZ-SV40pA (beta-galactosidase) marker and a PGK-Neomycin-bGHpA selection cassette. Northern blot analysis indicated that no detectable transcript encoding the C-terminus is expressed from this allele. The N-terminus is expressed together with the introduced lacZ gene. LacZ is expressed in Sertoli cells. (J:225512)