SPERMATOCYTE-SPECIFIC TRANSCRIPTION BY CALMODULIN GENE-II PROMOTER INTRANSGENIC MICE

Transgenic mice carrying a fused gene of the 294-base upstream and 68- base leader sequences of a rat calmodulin gene, CaMII, and beta-galact osidase gene were made. Only spermatocytes expressed the transgene mRN A in the testes of four independent transgenic lines. The localization of transgene mRNA was consistent with that of the mouse endogenous Ca MII analyzed by in situ hybridization with the probe of 3'-noncoding r egion of mouse CaMII. Thus, this short promoter of CaMII evidently con ferred the expression of transgene only on spermatocytes but not on sp ermatogonia nor on spermatids of the testis. The rat CaMII promoter up to -294 contained no sequences that corresponded to any of the report ed sequence features of genes expressed in the testis. Therefore, this short promoter region of CaMII seemed to carry a certain novel machin ery for the spermatocyte-specific gene expression.