Testis-specific TTF-D binds to single-stranded DNA in the c-mos and Odf1 promoters and activates Odf1

We recently identified testis-specific nuclear factor binding sites in the testis-specific promoters of the cmos gene and the Odf1 gene, which are 80% identical. Here we characterize a testis-specific nuclear factor, TTF-D, w hich is able to complex with both binding sites and stimulates Odf1 promote r activity. TTF-D is detectable in mouse testis as early as day 11 postpart um and contains three peptides of 22, 25, and 35 kDa in size. Surprisingly, TTF-D binds specifically to its cognate double-stranded DNA binding site a s well as to its single-stranded DNA binding site. Both double-stranded and single-stranded binding site oligonucleotide DNA can specifically repress Odf1 promoter activity. Our results suggest that TTF-D is involved in posit ive transcription regulation of a pre-meiotic and a post-meiotic gene in th e testis.