The molecular characterisation of mitochondrial DNA deficient oocytes using a pig model

作者：Te‐Sha Tsai, Sonika Tyagi, Justin C. St. John · 发表于：Human Reproduction · 年份：2018 · DOI：10.1093/humrep/dey052 · 被引用次数：38 · 研究领域：Mitochondrial Function and Pathology、Reproductive Biology and Fertility、Epigenetics and DNA Methylation

STUDY QUESTION: What are the molecular differences between mitochondrial DNA (mtDNA)-deficient and mtDNA-normal oocytes and how does mitochondrial supplementation alter these? SUMMARY ANSWER: Changes to DNA methylation in a 5' cytosine-phosphate-guanine 3' (CpG) island in the mtDNA-specific replication factor (DNA polymerase gamma (POLG)) of mtDNA-deficient oocytes mediates an increase in mtDNA copy number by the 2-cell stage that positively modulates the expression of nuclear genes, which affect cellular and metabolic processes, following autologous mitochondrial supplementation. WHAT IS KNOWN ALREADY: Too few copies of mtDNA in mature oocytes can lead to fertilisation failure or preimplantation embryo arrest. mtDNA-deficient oocytes that progress to blastocyst express genes associated with poor cellular and metabolic processes, transcriptional activation and mitochondrial biogenesis. STUDY DESIGN, SIZE, DURATION: Using a pig oocyte model, we assessed mtDNA-deficient and mtDNA-normal oocytes during in vitro maturation for mtDNA variants and levels of DNA methylation in POLG. We supplemented mtDNA-deficient oocytes with autologous populations of mitochondria to determine if there were changes to DNA methylation in POLG that coincided with increases in mtDNA copy number. We assessed metaphase II mtDNA-deficient and mtDNA-normal oocytes by RNA sequencing to identify differentially expressed genes and compared their profiles to blastocysts derived from mtDNA-normal, mtDNA-defici...