Mechanisms of sexual dimorphism of IFNτ secretion in bovine blastocyst

牛胚胎IFNτ基因表达的性别差异不是通过影响IFNτ基因表达的转录因子表达的性别差异引起的。而DNA甲基转移酶Dnmt 3a在牛雄胚中的表达量显著高于雌胚。此外，在牛胚胎培养液中加入DNA甲基转移酶抑制剂5-氮脱氧胞苷（5-azadeoxycytidene），可抑制牛胚胎IFNτ的性二型分泌。这些结果提示，牛胚胎基因组DNA甲基化可能参与了牛胚胎IFNτ性二态表达的发生。

Sexual dimorphic expression of IFNτ of bovine embryo was not caused via the sexual difference of expression of transcription factors, which affect IFNτ gene expression. However, the expression of Dnmt3a, one of DNA methyltransferases, of bovine male blastocysts was significantly higher than that of female embryos. Moreover, addition of 5-azadeoxycytidene, an inhibitor of DNA methyltransferase, to the culture medium of bovine embryo abolished the sexual dimorphic secretion of IFNτ from bovine embryos. These results suggest that the DNA methylation of bovine embryo genome might be involved in the occurrence of sexual dimorphic expression of IFNτ in bovine embryos.