Numerous studies have reported the presence of dynein-and kinesin-like motor proteins in the testis. Using an antibody raised against bovine brain MAP1C (microtubule-associated protein 1C), Yoshida and coworkers localized cytoplasmic dynein, in the testis, to spermatid manchettes (microtubule-rich organelles associated with the posterior aspect of the nucleus). They also noted a moderately intense staining of Sertoli cells. In a separate study, and using a different antibody, dynein was observed not only in spermatid manchettes and in Sertoli cell cytoplasm but also in ectoplasmic specializations associated with spermatids during early stages of differentiation. Kinesin has been detected in the spermatid manchette and the Sertoli cell trans-Golgi network. buy cipro
In addition, the het-erotrimeric motor protein kinesin-II has been localized in the midpiece and flagellum of echinoderm sperm. The subunits of this protein show considerable sequence homology with the mouse kinesin-like proteins KIF3A and KIF3B. Interestingly, Western blot analysis of testis homogenate has indicated high levels of KIF3B. No studies have described the localization of this protein in the testis. Similarly, no kinesins or dyneins have been localized to Sertoli cell junction plaques or crypt regions at stages of spermatogenesis during which spermatid translocation occurs.