EXPRESSION OF HEAT-SHOCK FACTOR-2 IN MOUSE TESTIS - POTENTIAL ROLE ASA REGULATOR OF HEAT-SHOCK PROTEIN GENE-EXPRESSION DURING SPERMATOGENESIS

We have examined the expression and function of heat shock transcripti on factor 2 (HSF2) in spermatogenic cells of mouse testis. The results of in situ RNA hybridization analysis, RNA filter hybridization, and reverse transcription-polymerase chain reaction (RT-PCR) analysis indi cate that HSF2 mRNA expression in testis is subject to developmental a nd cell type-dependent, as well as stage-dependent, regulation. Locali zed expression of HSF2 mRNA in testis first appears between Day 14 and Day 21 of postnatal development. In adult testis, HSF2 mRNA is found at highest levels in spermatocytes and round spermatids. Immunocytoche mical staining and gel mobility shift analysis demonstrate that HSF2 p rotein is localized to the nuclei of spermatocytes and round spermatid s and that this transcription factor exists in testis in a constitutiv ely active DNA binding state. We further demonstrate that the constitu tive HSF2 DNA-binding activity present in testis is able to interact w ith promoter sequences of the hsp70.2 gene, a testis-specific member o f the hsp70 gene family. Taken together, our results show that the exp ression and functional properties of HSF2 are regulated in spermatogen ic cell types of the mouse testis, supporting a role far this transcri ption factor as a regulator of hsp gene expression during spermatogene sis.