title: Spetex-1: a new component in the middle piece of flagellum in rodent spermatozoa.
abstract: Spetex-1 has recently been isolated by differential display and screening of cDNA library. It encodes a protein of 556 amino acid residues possessing coiled-coil motifs. In the rat seminiferous tubules (ST), Spetex-1 was expressed in the cytoplasm of elongating spermatids. To examine the subcellular distribution of Spetex-1 in mature spermatozoa, we performed biochemical and immunocytochemical approaches. We found that Spetex-1 that was synthesized in the cytoplasm of elongating spermatids was subsequently integrated as a middle piece component into spermatozoa during spermiogenesis. After integration, the majority of Spetex-1 in spermatozoa could be extracted by 6M urea under reduced condition but not released by the treatment of 1% Triton X-100. Immunoelectron microscopy demonstrated that Spetex-1 seemed to locate at the inner side of outer dense fibers (ODFs) in the middle piece or the narrow space between ODFs and axoneme. Spetex-1 might be involved in the stability of the structural complexity comprising axoneme and ODFs in the middle piece of sperm flagellum.
authors.affiliation: Laboratory of Zoology, Graduate School of Agriculture, Kyushu University, Higashiku Hakozaki 6-10-1, Fukuoka, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iida
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Honda
authors.forename: Takuya
authors.initials: T
authors.lastname: Matsuyama
authors.forename: Yosaburo
authors.initials: Y
authors.lastname: Shibata
authors.forename: Tetsuichiro
authors.initials: T
authors.lastname: Inai
mesh_terms: D000818:Animals; D003593:Cytoplasm / Q000737:chemistry; D015151:Immunoblotting; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D016253:Microscopy, Immunoelectron / Q000379:methods; D024101:Mitochondrial Proteins; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012680:Sensitivity and Specificity; D013082:Sperm Tail / Q000737:chemistry*; D013091:Spermatogenesis / Q000235:genetics / Q000502:physiology; D013094:Spermatozoa / Q000502:physiology*; D013737:Testis / Q000502:physiology; D000094323:Sperm Proteins
chemical_list: D024101:Mitochondrial Proteins; D011506:Proteins; C499424:Spata18 protein, rat; C510989:SPATA18 protein, mouse; D000094323:Sperm Proteins