Kaneko T, Iwamoto S, Murayama E, Kurio H, Inai T, Oda S, Iida H. Immunolocalization of spetex-1 at the connecting piece in spermatozoa of the musk shrew (Suncus murinus).
Zoolog Sci 2011;
28:444-52. [PMID:
21627455 DOI:
10.2108/zsj.28.444]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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.
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