title: Immunolocalization of spetex-1 at the connecting piece in spermatozoa of the musk shrew (Suncus murinus).
abstract: Spetex-1, which has been isolated by differential display and rat cDNA library screening as a haploid spermatid-specific gene, encodes a protein with two coiled-coil motifs that locates at both the segmented column in the connecting piece and outer dense fibers-affiliated satellite fibrils in rat sperm flagella. Orthologs of Spetex-1 are identified in many animal species, including human, chimpanzee, macaque, cow, dog, African clawed frog, green spotted puffer, and zebrafish. In this study, we used RT-PCR in combination with 5' and 3' RACE (Rapid Amplification of cDNA End) technique to isolate Spetex-1 ortholog of the musk shrew (Suneus murinus), which yielded a full-length Suncus Spetex-1 gene containing an open reading frame of 1,908 base pairs encoding a protein of 636 amino acids with the predicted molecular mass of 72,348 Da. Suncus Spetex-1 has two coiled-coil motifs at 118-184 and 242-276 amino acid residues, which is a characteristic shared by mammalian Spetex-1 proteins. To examine the subcellular localization of Spetex-1 in Suncus spermatozoa, we produced the anti-Suncus Spetex-1 antibody and carried out immunocytochemistry. In spite of that the primary structure of Suncus Spetex-1 is basically similar to that of rat and mouse Spetex-1, confocal laser scanning microscopy and immunoelectron microscopy revealed that Spetex-1 was restricted to the segmented column and capitulum in the connecting piece of Suncus spermatozoa and was not detected in other parts of flagella, suggesting a diversity of Spetex-1 localization in mammalian spermatozoa.
authors.affiliation: Laboratory of Zoology, Graduate School of Agriculture, Kyushu University, Higashiku Hakozaki 6-10-1, Fukuoka 812-8581, Japan.
authors.forename: Takane
authors.initials: T
authors.lastname: Kaneko
authors.forename: Shizuka
authors.initials: S
authors.lastname: Iwamoto
authors.forename: Emi
authors.initials: E
authors.lastname: Murayama
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kurio
authors.forename: Tetsuichiro
authors.initials: T
authors.lastname: Inai
authors.forename: Senichi
authors.initials: S
authors.lastname: Oda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iida
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D015151:Immunoblotting; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D021381:Protein Transport / Q000502:physiology*; D012788:Shrews / Q000502:physiology*; D013094:Spermatozoa / Q000166:cytology* / Q000378:metabolism*