Stage-specific enhanced expression of mitochondrial fusion and fission factors during spermatogenesis in rat testis.
The mitochondrial fusion factors mitofusins 1 and 2 (Mfn1 and Mfn2) and the fission factor dynamin-related protein 1 (Drp1) were found to be highly expressed in the pubertal and adult rat testis by Northern blot analysis. Immunohistochemistry using specific antisera to Mfn2 and Drp1 revealed a pronounced expression of the fusion and fission factors in the round and elongating spermatids in the seminiferous tubules, suggesting that at precise steps of spermiogenesis (i.e., steps 8-12), spermatid mitochondria are rapidly homogenized by frequent fusion and division. Although physiological relevance of this phenomenon remains to be clarified, a role is proposed for it as an effective means of achieving complete and homogeneous ubiquitination of mitochondria, which has recently been demonstrated to be a mechanism for the elimination of paternal mitochondria during fertilization, based on the fact that the timing of expression of Mfn2 and Drp1 coincides well with that reported for a spermatid-specific ubiquitin-conjugating enzyme.
Honda
Shinji
S
Department of Biological Sciences, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
Hirose
Shigehisa
S
D000818:Animals; D019556:COS Cells; D002453:Cell Cycle / Q000502:physiology; D002522:Chlorocebus aethiops; D034281:Dynamins / Q000235:genetics / Q000378:metabolism*; D020558:GTP Phosphohydrolases; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins; D008928:Mitochondria / Q000378:metabolism / Q000648:ultrastructure; D033681:Mitochondrial Membrane Transport Proteins; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D013091:Spermatogenesis / Q000502:physiology*; D013737:Testis / Q000166:cytology* / Q000378:metabolism*
D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D033681:Mitochondrial Membrane Transport Proteins; D024101:Mitochondrial Proteins; D020558:GTP Phosphohydrolases; C470018:MFN2 protein, human; C470017:Mfn1 protein, human; D034281:Dynamins