Study of mitochondrial fusion trancripts and proteins in mouse oocytes and embryos

• Grant number: 11/09944-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2011
• End date: February 29, 2012
• Field of knowledge: Biological Sciences - Genetics - Animal Genetics
• Principal Investigator: Marcos Roberto Chiaratti
• Grantee: Laís Gonzaga Machado Snidei
• Host Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil

Abstract

Mitochondrial dysfunctions caused by mitochondrial DNA (mtDNA) mutations are an important group of maternal-inherited human pathologies. Since no efficient treatment is available to treat these pathologies, researches have being focused on preventing their transmission to next generation. However, it is not possible to predict the risk of an affected woman transmit the pathology to her offspring. There is evidence that pathogenic mtDNA mutations are eliminated within few generations. Mutant and wild-type molecules of mtDNA may coexist in a cell, tissue or individual and the phenotypic outcome of the pathology is dependent on mutation load. The effect of these mutations on mitochondrial function can be minimized by the fusion of mutant and wild-type mitochondria because this lowers mutant load. During preimplantation, mtDNA is not replicated and only 1-2 mtDNA copies are found in a single mitochondrion. This reduced number of copies per organelle seems to enhance the effect of mutations on organelle function, which might eliminate mitochondria containing mutant mtDNA (e.g. mitophagy). In this context, it is reasonable to consider that during the earliest stages of development mitochondrial fusion is not effective, leading mutant molecules to be distinguished from wild-type ones due to their effect on organelle function. Thereafter, the aim of this work is to investigate, in mouse oocytes and embryos, the presence of key factors (Mfn1, Mfn2 and Opa1) regulating mitochondrial fusion. (AU)