Cytoplasmic maturation of bovine oocytes: Structural and biochemical modifications and acquisition of developmental competence

Autor(es)

Ferreira, E. M. ^[1] ; Vireque, A. A. ; Adona, P. R. ^[2] ; Meirelles, F. V. ^[2] ; Ferriani, R. A. ; Navarro, P. A. A. S.

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, HCFMRP, Setor Reprod Humana, Fac Med Ribeirao Preto, Dept Gynecol & Obstet, BR-14048900 Ribeirao Preto - Brazil

^[2] Univ Sao Paulo, Fac Zootechny & Aliments Engn, Dept Basic Sci, BR-13630970 Pirassununga, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Theriogenology; v. 71, n. 5, p. 836-848, MAR 15 2009.
• Citações Web of Science: 138

Resumo

Oocyte maturation is a long process during which oocytes acquire their intrinsic ability to support the subsequent stages of development in a stepwise manner, ultimately reaching activation of the embryonic genome. This process involves complex and distinct, although linked, events of nuclear and cytoplasmic maturation. Nuclear maturation mainly involves chromosomal segregation, whereas cytoplasmic maturation involves organelle reorganization and storage of mRNAs, proteins and transcription factors that act in the overall maturation process, fertilization and early embryogenesis. Thus, for didactic purposes, we subdivided cytoplasmic maturation into: (1) organelle redistribution, (2) cytoskeleton dynamics, and (3) molecular maturation. Ultrastructural analysis has shown that mitochondria, ribosomes, endoplasmic reticulum, cortical granules and the Golgi complex assume different positions during the transition from the germinal vesicle stage to metaphase II. The cytoskeletal microfilaments and microtubules present in the cytoplasm promote these movements and act on chromosome segregation. Molecular maturation consists of transcription, storage and processing of maternal mRNA, which is stored in a stable, inactive form until translational recruitment. Polyadenylation is the main mechanism that initiates protein translation and consists of the addition of adenosine residues to the 3' terminal portion of mRNA. Cell cycle regulators, proteins, cytoplasmic maturation markers and components of the enzymatic antioxidant system are mainly transcribed during this stage. Thus, the objective of this review is to focus on the cytoplasmic maturation process by analyzing the modifications in this compartment during the acquisition of meiotic competence for development. (c) 2009 Elsevier Inc. All rights reserved. (AU)

• Processo FAPESP: 05/57852-2 - Inibição da quebra da vesícula germinativa de complexos cumulus-oócito bovinos cultivados com butirolactona I, seguida por maturação in vitro: efeitos sobre o fuso meiótico oocitário
• Beneficiário: Elisa Melo Ferreira
• Modalidade de apoio: Bolsas no Brasil - Mestrado