title: Cloning, characterization and primary function study of a novel gene, Cymg1, related to family 2 cystatins.
abstract: Cystatins are cysteine proteinase inhibitors. We found two expression sequence tags (ESTs), CA463109 and AV042522, from a mouse testis library using Digital differential display (DDD). By electrical hybridization, a novel gene, Cymg1 (GenBank accession No. AY600990), which has a full length of 0.78 kb, and contains four exons and three introns, was cloned from a mouse testis cDNA library. The gene is located in the 2G3 area of chromosome 2. The full cDNA encompasses the entire open reading frame, encoding 141 amino acid residues. The protein has a cysteine protease inhibitor domain that is related to the family 2 cystatins but lacks critical consensus sites important for cysteine protease inhibition. These characteristics are seen in the CRES subfamily, which are related to the family 2 cystatins and are expressed specifically in the male reproductive tract. CYMG1 has a 44% (48/108) identity with mouse CRES and 30% (42/140) identity with mouse cystatin C. Northern blot analysis showed that the Cymg1 is specifically expressed in adult mouse testes. Cell location studies showed that the GFP-tagged CYMG1 protein was localized in the cytoplasm of HeLa cells. Immunohistochemistry revealed that the CYMG1 protein was expressed in mouse testes spermatogonium, spermatocytes, round spermatids, elongating spermatids and spermatozoa. RT-PCR results also showed that Cymg1 was expressed in mouse testes and spermatogonium. The Cymg1 expression level varied in different developmental stages: it was low 1 week postpartum, steadily increased 2 to 5 weeks postpartum, and was highest 7 weeks postpartum. The expression level at 5 weeks postpartum was maintained during 13 to 57 weeks postpartum. The Cymg1 expression level in the testes over different developmental stages correlates with the mouse spermatogenesis and sexual maturation process. All these indicate that Cymg1 might play an important role in mouse spermatogenesis and sexual maturation.
authors.affiliation: Human Reproductive and Stem Cell Engineering Institute, Central South University, Changsha 410078, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Xiang
authors.forename: Dong-Song
authors.initials: DS
authors.lastname: Nie
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Tan
authors.forename: Yun
authors.initials: Y
authors.lastname: Deng
authors.forename: Shu-Wei
authors.initials: SW
authors.lastname: Luo
authors.forename: Guang-Xiu
authors.initials: GX
authors.lastname: Lu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D019295:Computational Biology; D015891:Cystatins / Q000235:genetics* / Q000502:physiology*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D018076:DNA, Complementary / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D005091:Exons; D020224:Expressed Sequence Tags; D015723:Gene Library; D005854:Germ Cells / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007150:Immunohistochemistry; D007438:Introns; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D010957:Plasmids / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012313:RNA / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D013091:Spermatogenesis; D013696:Temperature; D013737:Testis / Q000378:metabolism / Q000473:pathology; D014162:Transfection
chemical_list: C502730:Cymg1 protein, mouse; D015891:Cystatins; D015853:Cysteine Proteinase Inhibitors; D018076:DNA, Complementary; D049452:Green Fluorescent Proteins; D012313:RNA