Connexin Gene Expression in Seminiferous Tubules of the Sprague-Dawley Rat1

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Abstract
Sertoli and spermatogenic cells establish germ cell- and epithelial stage-dependent networks of cell-cell communication thought to be important for the initiation and maintenance of spermatogenesis. Since gap junctions assemble between Sertoli cells and between Sertoli and spermatogenic cells, it was hypothesized that multiple, unique routes of cell-cell communication may be established, in part, by the assembly of structurally diverse gap junctions from the connexin (Cx) multigene family. Differences in channel structure may support differences in ion or second messenger permeability between cell types. Reverse transcription-polymerase chain reaction (RT-PCR) analyses showed that 11 Cx mRNAs were present in total RNA from seminiferous tubules and that 10 of the Cx mRNAs were present in polysomes and presumably translated. RT-PCR analyses also showed that the Cx mRNA population varied between different seminiferous tubule cell types. There were 9 Cx mRNAs in germ cells, 8 in Sertoli cells, and 5 in peritubular cells. One of the Cx mRNAs, Cx-50, was detected only in pachytene spermatocytes and round spermatids. Comparisons of the Cx mRNAs present in tubules at different postnatal ages showed that at least 2 Cxs (Cx-33 and Cx-50) accumulated when leptotene-zygotene stages developed. The multiple Cx genes and proteins produced in spermatogenesis may support the assembly of structurally diverse gap junctions.