Fleming Jo-Ann G W, Song Gwonhwa, Choi Youngsok, Spencer Thomas E, Bazer Fuller W
Center for Animal Biotechnology and Genomics and Department of Animal Science, Texas A&M University, College Station, TX 77843, USA.
Mol Cell Endocrinol. 2009 Feb 27;299(2):252-60. doi: 10.1016/j.mce.2008.10.025. Epub 2008 Oct 30.
Interferon tau (IFNT), the maternal recognition of pregnancy signal in sheep and other ruminants, is secreted by the conceptus and regulates the expression of a number of genes in a cell-specific manner within the uterus. The response of different endometrial cell types to IFNT appears to be specified by IFN regulatory factors (IRFs). IRF2, a potent repressor of gene transcription, is expressed only by luminal (LE) and superficial glandular epithelia (sGE), whereas IRF1 and IRF9, activators of gene transcription, are expressed only in GE and stromal cells of the uterus during early pregnancy. In the present study, IRF6 was found to be expressed in LE/sGE and middle GE of the ovine uterine endometrium as well as conceptus trophectoderm. IRF family members can regulate transcription via IFN-stimulated response elements (ISREs). Transient transfection analyses found that IRF6 enhanced basal activity of ISRE-containing promoters, but did not enhance IFNT stimulation of ISRE-containing promoters in variety of different cell types. Further, IRF6 did not cooperate with IRF1 or reduce IRF2 repression of ISRE-containing promoter activity. These results establish that IRF6 is a transcriptional activator that is preferentially expressed in the endometrial epithelia and conceptus trophectoderm. IRF6 is hypothesized to play critical roles in endometrial gene expression as well as in conceptus trophectoderm growth and differentiation.
干扰素τ（IFNT）是绵羊和其他反刍动物中母体识别妊娠的信号，由孕体分泌，并以细胞特异性方式调节子宫内许多基因的表达。不同子宫内膜细胞类型对IFNT的反应似乎由干扰素调节因子（IRF）决定。IRF2是一种强大的基因转录抑制因子，仅在腔上皮（LE）和浅表腺上皮（sGE）中表达，而基因转录激活因子IRF1和IRF9仅在妊娠早期子宫的腺上皮（GE）和基质细胞中表达。在本研究中，发现IRF6在绵羊子宫内膜的LE/sGE和中GE以及孕体滋养外胚层中表达。IRF家族成员可通过干扰素刺激反应元件（ISRE）调节转录。瞬时转染分析发现，IRF6增强了含ISRE启动子的基础活性，但在多种不同细胞类型中并未增强IFNT对含ISRE启动子的刺激。此外，IRF6不与IRF1协同作用，也不降低IRF2对含ISRE启动子活性的抑制作用。这些结果表明，IRF6是一种转录激活因子，优先在子宫内膜上皮和孕体滋养外胚层中表达。据推测，IRF6在子宫内膜基因表达以及孕体滋养外胚层的生长和分化中起关键作用。
