Localization and roles of actin and its regulation substances, microtubules, and water channels in spematogenesis.

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Spermiogenesis is characterized by prominent morphological changes and the reduction of cell volume. It has been pointed out that actin filaments and microtubules are involved in morphogenesis, and aquaporins (AQPs), water channel molecules, are involved in volume reduction. In the present study, their involvements were analyzed by immuno-histochemistry, electron microscopy, and KO-mouse(KO-M)(1)Localization of AQP7,8,11 in germinal epithelium : It was shown that AQP7 and 11 located in the germ cells, and AQP8 located in the Sertoli cells. The result suggests that AQP7 and 11 compensate each other.(2)Analysis of spermatogenesis in AQP7-KO-M : Signet-ring like pattern representing abnormal nuclear condensation was observed in the half individuals of the KO-mice. It suggests that AQP7 is involved at least in nuclear condensation.(3)Metamorphic sperm formation in GOPC-KO-M : In GOPC(Golgi-associated PDZ-and coiled coil motif-containing protein)-KO-M, spermatozoa are infertile with round h … More ead and coiled tail. In the present study, we have investigated the process to make such morphological abnormalities. In the early spermatids, the acroplaxome, which is a sheet mainly made of actin, and bonds acrosome and the nucleus together, was formed. Acrosomal vesicles of KO-M failed to keep contact with the nucleus and to fuse each other. Then abnormal sperm formation was induced like a domino collapse. Namely, disappearance of acrosomal vesicle→deficiency of the perinuclear ring, which is the marginal structure of the acroplaxome→defective formation of the manchette made of microtubules→deficiency of the posterior ring and the presence of perinuciear cytoplasm. These results suggest that the actin and microtubules are involved in the morphogenesis in spermiogenesis. On the other hand, flagella were made normally in the testis. However, the flagella rolled up around the nucleus during the passage through the middle caput epididymidis, where the cytoplasmic drolets migrate from the neck region to the distal part of the mid-piece. It suggest that the tail coiling occur in relation with the migration of the cytoplasmic droplet. Less