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

Figure 3

Changes in histone posttranslational modifications in low dose BPA-exposed metaphase II mouse oocytes. (a-b′) Images of histone H3K9 trimethylation in control and BPA-exposed oocytes: some unaligned chromosomes (b) and reduced trimethylated pericentromeric heterochromatin (b′) in the BPA group. (c-d′) Unchanged pattern of histone H4K12 acetylation. (e) Decreased distance between centromeres of sister chromatids in metaphase II chromosomes of BPA-exposed oocytes (blue) shown in fixed oocytes that were stained by CREST autoantibodies for centromeres (red). (f) Model indicating relevance of H3K9 trimethylation for recruitment of Dnmts (right side) and other factors like ATRX (ATP-dependent helicase that belongs to SWI/SNF family of chromatin remodelling factors) and Aurora kinase that might play a role in centromere regulation, microtubule attachment, and chromosome alignment through phosphorylation of different target proteins and histone H3S10 (left side). For further explanation, see text and [76].