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Michael Risley1 *, Lucy Perrone1 , Eiman Ramzi1 , Natalia Yemelynova1
Department of Biological Sciences, Fordham University, Bronx, N.Y. 10458 1
Gap junctions are present between rat Sertoli cells, Sertoli and spermatogenic cells and between peritubular cells. Previous studies from this lab have shown that seminiferous tubule cells contain mRNAs for 10 gap junction proteins (connexins) and that 9 are present on polysomes (Ramzi et al 1997, J Cell Biol: 418). This suggests that gap junctions in tubules may be structurally diverse and cell-type specific. To further explore this, different cell types were isolated and connexin mRNA content assayed by RT-PCR. Liver contained mRNAs for four connexins (Cxs 26, 32, 37, 45). In contrast, pachytene spermatocytes and round spermatids from adult rats both contained nine connexin mRNAs (Cxs 26, 31, 32, 33, 37, 40, 43, 45, 50). Sertoli cells from 20-day rats also contained the same nine connexin mRNAs as germ cells. The predominant connexin mRNAs in 20 day peritubular cells were Cxs 31, 37, 40, 43 and 45. Immunocytochemistry on testis cryosections showed only Cx45 on germ cell surfaces, Cx45 between peritubular cells, and connexins 33 and 43 between Sertoli cells. Several connexin proteins (Cx26, 32, 33, 40,43, 45) were also localized to germ cell cytoplasmic compartments in a stage-dependent pattern. These data suggest that the regulation of connexin protein synthesis and assembly into gap junctions is predominantly posttranslational in spermatogenic and Sertoli cells and may result in assembly of multiple communication compartments in tubules. Expression of numerous connexins by germ cells may also allow a functional redundancy that compensates for individual connexin gene mutations. This material is based upon work supported by the National Science Foundation under Grant No. IBN-9722987.
This abstract is being presented on Tuesday, August 3 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.