Testis hormone-sensitive lipase expression in spermatids is governed by a short promoter in transgenic mice

A testicular form of hormone-sensitive lipase (HSLtes), a triacylglycerol l ipase, and cholesterol esterase, is expressed in male germ cells. Northern blot analysis showed HSLtes mRNA expression in early spermatids. Immunoloca lization of the protein in human and rodent seminiferous tubules indicated that the highest level of expression occurred in elongated spermatids. We h ave previously shown that 0.5 kilobase pairs of the human HSLtes promoter d irects testis-specific expression of a chloramphenicol acetyltransferase re porter gene in transgenic mice and determined regions binding nuclear prote ins expressed in testis but not in liver (Blaise, R,, Grober, J,, Rouet, P. , Tavernier, G., Daegelen, D., and Langin, D. (1999) J. Biol. Chem. 274, 93 27-9334). Mutation of a SRY/Sox-binding site in one of the regions did not impair in vivo testis-specific expression of the reporter gene. Further tra nsgenic analyses established that 95 base pairs upstream of the transcripti on start site were sufficient for correct testis expression. In gel retarda tion assays using early spermatid nuclear extracts, a germ cell-specific DN A-protein interaction was mapped between -46 and -29 base pairs. The DNA bi nding nuclear protein showed properties of zinc finger transcription factor s. Mutation of the region abolished reporter gene activity in transgenic mi ce, showing that it is necessary for testis expression of HSLtes.