Embryo Mitochondrial DNA Depletion Is Reversed During Early Embryogenesis in Cattle

Autor(es)

Chiaratti, Marcos R. ^{[1, 2]} ; Bressan, Fabiana F. ^[2] ; Ferreira, Christina R. ^[2] ; Caetano, Alexandre R. ^{[3, 2]} ; Smith, Lawrence C. ^{[4, 2]} ; Vercesi, Anibal E. ^[1] ; Meirelles, Flavio V. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Dept Patol Clin, Fac Ciencias Med, Campinas, SP - Brazil

^[2] Univ Sao Paulo, Dept Ciencias Basicas, Fac Zootecnia & Engn Alimentos, BR-13635900 Pirassununga, SP - Brazil

^[3] EMBRAPA Recursos Genet & Biotecnol, Brasilia, DF - Brazil

^[4] Univ Montreal, Fac Med Vet, Ctr Rech Reprod Anim, St Hyacinthe, PQ J2S 7C6 - Canada

• Tipo de documento: Artigo Científico
• Fonte: BIOLOGY OF REPRODUCTION; v. 82, n. 1, p. 76-85, JAN 2010.
• Citações Web of Science: 43

Resumo

The extensive replication of mitochondria during oogenesis and the wide variability in mitochondrial DNA ( mtDNA) copy numbers present in fully grown oocytes indicate that mtDNA amount may play an important role during early embryogenesis. Using bovine oocytes derived from follicles of different sizes to study the influence of mtDNA content on development, we showed that oocytes obtained from small follicles, known to be less competent in developing into blastocysts, contain less mtDNA than those originating from larger follicles. However, because of the high variability in copy number, a more accurate approach was examined in which parthenogenetic one-cell embryos were biopsied to measure their mtDNA content and then cultured to assess development capacity. Contrasting with previous findings, mtDNA copy number in biopsies was not different between competent and incompetent embryos, indicating that mtDNA content is not related to early developmental competence. To further examine the importance of mtDNA on development, one-cell embryos were partially depleted of their mtDNA (64% +/- 4.1% less) by centrifugation followed by the removal of the mitochondrial-enriched cytoplasmic fraction. Surprisingly, depleted embryos developed normally into blastocysts, which contained mtDNA copy numbers similar to nonmanipulated controls. Development in depleted embryos was accompanied by an increase in the expression of genes (TFAM and NRF1) controlling mtDNA replication and transcription, indicating an intrinsic ability to restore the content of mtDNA at the blastocyst stage. Therefore, we concluded that competent bovine embryos are able to regulate their mtDNA content at the blastocyst stage regardless of the copy numbers accumulated during oogenesis. (AU)

• Processo FAPESP: 06/59074-0 - Efeito da quantidade de mitocôndrias e de DNA mitocondrial sobre o desenvolvimento embrionário bovino: dois modelos originais
• Beneficiário: Flávio Vieira Meirelles
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 06/03516-4 - Efeito da quantidade de mitocôndrias e de DNA mitocondrial sobre o desenvolvimento embrionário bovino: dois modelos originais
• Beneficiário: Marcos Roberto Chiaratti
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto