Transcription inhibition of the somatic-type phosphoglycerate kinase 1 genein vitroby a testis-specific factor that recognizes a sequence similar to the binding site for Ets oncoproteins

To elucidate the mechanism by which transcription of the somatic-type phosphoglycerate kinase 1 gene is inactivated during mammalian spermatogenesis, we examined the presence of specific transcription inhibitor(s) in the testis by a cell-free transcription system. Transcription of the mouse phosphoglycerate kinase 1 gene using nuclear extracts of the rat liver was significantly inhibited by the addition of testis extracts, whereas brain extracts had little effect. Transcription inhibition required the binding of a testis-specific factor, designated TIN-1, to the region between positions -268 and -259 relative to transcription initiation site at +1. This region had the sequence 5'-AGGAAGTTCC-3' that includes an inverted repeat of the binding motif, 5'-GGAA-3', for the oncoprotein Ets. A UV-crosslinking experiment revealed that 43- and 45-kDa polypeptides present in testis extracts bind to that sequence. These results suggest that a testis-specific transcription inhibitor TIN-1 inactivates the phosphoglycerate kinase 1 gene in the mammalian spermatogenic pathway.