title: Human RING finger protein ZNF645 is a novel testis-specific E3 ubiquitin ligase.
abstract: A large number of testis-specific genes are involved in the complex process of mammalian spermatogenesis. Identification of these genes and their roles is important for understanding the mechanisms underlying spermatogenesis. Here we report on a novel human RING finger protein, ZNF645, which contains a C3HC4 RING finger domain, a C2H2 zinc-finger domain, and a proline-rich region, indicating that it has a structure similar to that of the c-Cbl-like protein Hakai. ZNF645 was exclusively expressed in normal human testicular tissue. Immunohistochemical analysis confirmed that ZNF645 protein was present in spermatocytes, round and elongated spermatids, and Leydig cells. Immunofluorescence staining of mature sperms further showed that the ZNF645 protein was localized over the postacrosomal perinuclear theca region and the entire length of sperm tail. An in vitro ubiquitination assay indicated that the RING finger domain of the ZNF645 protein had E3 ubiquitin ligase activity. Therefore, we suggest that ZNF645 might act as an E3 ubiquitin-protein ligase and play a role in human sperm production and quality control.
authors.affiliation: Department of Medical Genetics, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China.
authors.forename: Yun-Qiang
authors.initials: YQ
authors.lastname: Liu
authors.forename: Gang
authors.initials: G
authors.lastname: Bai
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.forename: Dan
authors.initials: D
authors.lastname: Su
authors.forename: Da-Chang
authors.initials: DC
authors.lastname: Tao
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yang
authors.forename: Yong-Xin
authors.initials: YX
authors.lastname: Ma
authors.forename: Si-Zhong
authors.initials: SZ
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D015870:Gene Expression; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D054829:RING Finger Domains; D013090:Spermatocytes / Q000737:chemistry*; D013091:Spermatogenesis / Q000235:genetics*; D013737:Testis / Q000737:chemistry*; D015534:Trans-Activators / Q000096:biosynthesis / Q000235:genetics*; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics*; D044767:Ubiquitin-Protein Ligases / Q000096:biosynthesis / Q000235:genetics*; D054875:Ubiquitination
chemical_list: C552601:CBLL2 protein, human; D015534:Trans-Activators; D014157:Transcription Factors; C573234:ZNF644 protein, human; D044767:Ubiquitin-Protein Ligases