Abstract: 273

POST TRANSLATIONAL PHOSPHORYLATION OF THE GAP JUNCTION PROTEIN CONNEXIN 43 (Cx43) DURING NORMAL POSTNATAL TESTICULAR DEVELOPMENT AND FOLLOWING SPONTANEOUS AUTOIMMUNE ORCHITIS IN THE MINK.

R-M Pelletier^{1 *}, ME Carbajal¹ , ML Vitale¹
Pathology and Cell Biol. U. de Montreal, Quebec, H3T 1J4, Canada ¹

The mink, Mustela vison, is an animal model with two advantages: 1) it is a seasonal breeder in which spermatogenesis is cyclically and reversibly arrested during the annual testicular regression and re-initiated for the next breeding season 2) it is model to study of immunological male infertility because some strains are spontaneously afflicted with secondary infertility that causes an autoimmune orchitis and spermatogenic arrest in the adult. Here, we compared the state of phosphorylation of Cx43 in seminiferous tubules during distinct phase of spermatogenic activity to establish whether phosphorylation is associated with junction assembly/disassembly. Testes of 25 normal (5 neonatal, 10 pubertal, 5 adults at the onset and 5 at the end of seasonal testicular regression) and 5 adults with autoimmune orchitis were used. Tubules were separated from the interstitial tissue. Immunoblots on preparations of tubules using affinity-purified polyclonal Cx43 antibody, showed a band at 42kDa in adult tubules harvested during the breeding season, but in neonatal, pubertal and adult tubules harvested at the beginning of testicular regression, immunoblots of the samples showed doublets, a band at 42 kDa and another at 44-46kDa. Phosphatase treatment of the samples eliminated the 44-46kDa band. Treatment with a phosphatase inhibitor restored the doublet suggesting the 44-46 kDa band was phosphorylated. Phosphorylation was maximal during periods of increased junction assembly and disassembly. Phosphorylated Cx43 was abundant at the beginning of testicular regression. We conclude that changes in the state of phosphorylation of Cx43 accompanies junction modulation and that Cx43 phosphorylation is increased during gap junction disassembly. NSERC OGP0041653 and OGP0194652.

    This abstract is being presented on Monday, August 2 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.