Involvement of BCL2 family members in the regulation of human oocyte and early embryo survival and death: gene expression and beyond

Reproduction. 2011 May;141(5):549-61. doi: 10.1530/REP-10-0504. Epub 2011 Feb 21.

Abstract

In women, up to 99.9% of the oocyte stockpile formed during fetal life is decimated by apoptosis. Apoptotic features are also detected in human preimplantation embryos both in vivo and in vitro. Despite the important consequences of cell death processes to oocyte competence and early embryonic development, little is known about its genetic and molecular control. B cell lymphoma-2 (BCL2) family proteins are major regulators of cell death and survival. Here, we present a literature review on BCL2 family expression and protein distribution in human and animal oocytes and early embryos. Most of the studies focused on the expression of two antagonistic members: the founding and survival family member BCL2 and its proapoptotic homolog BAX. However, recent transcriptomic analyses have identified novel candidate genes related to oocyte and/or early embryonic viability (such as BCL2L10) or commitment to apoptosis (e.g. BIK). Interestingly, some BCL2 proteins appear to be differentially distributed at the subcellular level during oocyte maturation and early embryonic development, a process probably linked to the functional compartmentalization of the ooplasm and blastomere. Assessment of BCL2 family involvement in regulating the survival of human oocytes and embryos may be of particular value for diagnosis and assisted reproductive technology. We suggest that implications of not only aberrant gene expression but also abnormal subcellular protein redistribution should be established in pathological conditions resulting in infertility.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Blastocyst / metabolism*
  • Blastocyst / pathology
  • Cell Death
  • Cell Survival
  • Female
  • Fertility
  • Gene Expression Regulation, Developmental
  • Humans
  • Infertility / genetics
  • Infertility / metabolism
  • Infertility / physiopathology
  • Oocytes / metabolism*
  • Oocytes / pathology
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • Proto-Oncogene Proteins c-bcl-2 / metabolism*
  • Signal Transduction*

Substances

  • Proto-Oncogene Proteins c-bcl-2