.1. Human Testis-specific Nuclear Pore Proteins Bs-63 Functional Studies Using Yeast Two-hybrid System To Find The Hsd-1 Protein-coding (hsmp-1) Conjugate

Spermatogenesis is regulated by lots of proteins, generally, these kinds of regulation protein are expressed under precise temporal and spatial regulation in sperm cells specifically. Therefore to elicit the functions of the proteins is of great value to delineate the mechanism of spermatogenesis.BS-63 is a human testis-specific nucleoporin isolated by our research group from testis λ ZAPII cDNA library by cloning selection, 5'RACE(Rapid Amplification cDNA End, RACE) and PCR. Its cDNA open reading frame encodes 1765 amino acids. Employing BLASTn software provided by NCBI web site, we found BS-63 had a high homology with the nucleoporin Nup358/RanBP2 which was isolated from human Hela cell expression library. The differences between them are the cDNA of BS-63 is shorter than that of Nup 358 from 2812bp to 5340bp, the C terminal end of BS-63 encoding part is also shorter than that of Nup 358 and with 375bp highly divergent with Nup 358. The 3' unencoding part of BS-63 is 106bp that is also shorter than the 889 bp of Nup358 3' encoding part. Except these differences, the nucleotides of BS-63 are high homology with those of Nup358. The 1765 amino acids encoded by the full length of BS-63 contain XFXFG or GLFG mortifs that are characteristics of nucleoporin. BS-63 was localized on the nuclear pore of spermatid by immunogold transmitting microscope and on the nuclear membrane of sperm by immunogold-silver scanning electron microscope. Based on these results, we regards BS-63 as a testis-specific nucleoporin, a specifically expressed way in testis of nucleoporin Nup358.As we know, hnmRNA transcripted in nuclei become mature mRNA after being spliced, then mature mRNA are translated into respective proteins in cytoplasm. Among these proeteins, regulation proteins have to be transported from cytoplasm into nuclei to fulfill their regulation functions. These regulation proteins play an important role in spermatogenesis. Since BS-63 is a human testis-specific nucleoporin, we wonder to know that among the cargoes transported by BS-63, if there is/are one/some cargo(es) which is/are also specifically expressed in testis. If there is/are, it/they may play a key role in spermatogenesis. By yeast two-hybrid system, BS-63 was used as a bait to screen human...