Bisphenol A Effects on Mammalian Oogenesis and Epigenetic Integrity of Oocytes: A Case Study Exploring Risks of Endocrine Disrupting Chemicals

Figure 2

Critical stages for epigenetic reprogramming of chromatin in mammalian female germ cells, including periods of imprint erasure during formation of primordial germ cells, maternal imprint establishment during oocyte growth, and imprint maintenance after fertilization of the egg and development to the blastocyst. Statuses of maternal imprints are indicated by red lines, of global methylation in maternal chromatin in dotted blue lines, of global paternal methylation in green dotted lines, and of development and tissue-specific methylation in orange dotted lines. Some enzymes that participate in demethylation (activation induced cytidine deaminase), DNA methylation (Dnmts), or maintenance of methylation (zinc finger protein 57, Zfp57; tripartite motive containing, Kap1/Trim28; developmental pluripotency associated 3, Stella/Dppa3) are indicated next to the respective lines showing changes in DNA methylation, adapted from [84].