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1998 Fiscal Year Final Research Report Summary

The Mechanism of Sperm/egg interaction and involved factors.

Research Project

Project/Area Number 09480246
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Laboratory animal science
Research InstitutionOsaka University

Principal Investigator

OKABE Masaru  Osaka University, Genome Information Research Center, Professor, 遺伝情報実験施設, 教授 (30089875)

Co-Investigator(Kenkyū-buntansha) YOSHIMURA Yasuhide  Osaka University, Research Institute for Microbial Diseases, Assistant Professor, 微生物病研究所, 教務職員 (60263307)
TANAKA Hiromitsu  Osaka University, Research Institute for Microbial Diseases, Assistant Professor, 微生物病研究所, 助手 (10263310)
YOMOGIDA Kentaro  Osaka University, Research Institute for Microbial Diseases, Assistant Professor, 微生物病研究所, 助手 (90283803)
NISHIMUNE Yoshitake  Osaka University, Research Institute for Microbial Diseases, Professor, 微生物病研究所, 教授 (80029793)
Project Period (FY) 1997 – 1998
Keywordsmolecular chaperone / homologous recombination / fertilization / calmegin / 実験動物 / 凍結保存
Research Abstract

The proper folding of newly synthesized membrane proteins in the endoplasmic reticulum (ER) is required for formation of functional mature proteins. Calnexin is a ubiquitous ER chaperone that plays afrnajor role in quality control by retaining incompletely or misfolded proteins. In contrast to other known chaperones (Hsps, BiP and calreticulin), calnexin is an integral membrane protein. Calmegin is a testis-specific ER protein that is homologous to calnexin. We report here that calmegin binds to nascent polypeptides during spermatogenesis and the physiological function of calmegin has been analyzed by targeted disruption of its gene. Homozygous null males were nearly sterile even though spermatogenesis was morphologically normal and mating was normal. In vitro, sperm from homozygous null males did not adhere to the egg extracellular matrix (zona pellucida), and this defect may explain the observed infertility. These results suggest that calmegin functions as a chaperone for one or more sperm surface proteins that mediate sperm-egg interactions. The defective zona pellucida adhesion phenotype of sperm from calmegin deficient mice is reminiscent of certain cases of human male unexplained infertility.

  • Research Products

    (12 results)

All Other

All Publications (12 results)

  • [Publications] Tanaka,H.et al.: "Cloning and characterization of the human Calmegin gene encoding putative testis-specific chaperone" Gene. 204. 159-63 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Ikawa,M.et al.: "The putative chaperone calmegin is required for sperm fertility." Nature. 387. 607-11 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yamagata,K.et al.: "Acrosin accelerates the dispersal of sperm acrosomal proteins during acrosome reaction" J.Biol.Chem.273. 10470-4 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Okabe,M.et al.: "Male infertility and the genetics of spermatogenesis 〔In Process Citation〕" Am J Hum Genet. 62. 1274-81 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Tsujimura,A. et al.: "Molecular cloning of a murine homologue of membrane cofactor protein (CD46) : preferential expression in testicular germ cells" Biochem J. 330. 163-168 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Okabe,M.et al.: "Green fluorescent protein and its usage in reproductive biology." Zygote. 6. 117 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H.Tanaka, M.Ikawa, J.Tsuchida, M.Nozaki, M.Suzuki, T.Fujiwara, M.Okabe and Y.Nishimune :"Cloning and characterization of the human Calmegin gene encoding putative testis-specific chaperone." Gene. 204. 159-63 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M.Ikawa, I.Wada, K.Kominaml, D.Watanabe, K.Toshimori, Y.Nishimune, and M.Okabe :"The putative chaperone calmegin is required for sperm fertility." Nature. 387. 607-11 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Yamagata, K.Maruyama, M.Okabe, K.Toshimori, T.Nakanishi, S.Kashiwabara and T.Baba: "Acrosin Accelerates the Dispersal of Sperm Acrosomal Proteins during Acrosome Reaction." J.Biol.Chem.273. 10470-4 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M.Okabe, M.Ikawa and J.Ashkenas :"Male Infertility and the Genetics of Spermatogenesis." Am.J.hum.Genet.62. 1274-81 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] A.Tsujimura, K.shida, M.Kitamura, M.Nomura, J.Takeda, H.Tanaka, M.Matsumoto, K.Matsumiya, A.Okuyama, Y.Nishimune, M.Okabe and T.Seya: "Molecular cloning of a murine homologue of membrane cofactor protein (CD46) : preferential expression in testicular germ cells." Biochem j.330. 163-8 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M.Okabe, M.Ikawa, T.Nakanishi, S.Yamada, T.Baba and Y.Nishimune :"Green fluorescent protein and its usage in reproductive biology." Zygote. 6. 117 (1998)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1999-12-08  

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