Spetex-1: A new component in the middle piece of flagellum in rodent spermatozoa

Hiroshi Iida, Yoshiko Honda, Takuya Matsuyama, Yosaburo Shibata, Tetsuichiro Inai

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


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. lmmunoelectron 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.

Original languageEnglish
Pages (from-to)342-349
Number of pages8
JournalMolecular Reproduction and Development
Issue number3
Publication statusPublished - Mar 2006

All Science Journal Classification (ASJC) codes

  • Genetics
  • Developmental Biology
  • Cell Biology


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