Regulation of the ovine interferon-tau gene by a blastocyst-speciflic transcription factor, Cdx2
Regulation of the ovine interferon-tau gene by a blastocyst-speciflic transcription factor, Cdx2
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DOI：
10.1002/mrd.20457
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发表时间：
2006-05-01
影响因子：
2.5
通讯作者：
Christenson, RK
中科院分区：
文献类型：
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作者：
Imakawa, K;Kim, MS;Christenson, RK
绵羊干扰素-tau（oIFN tau）是反刍动物有蹄动物母体识别妊娠过程中必不可少的因子，其表达仅限于滋养层。然而，oIFN tau表达仅限于滋养外胚层的分子机制尚未完全阐明。本研究的目的是确定oIFN tau基因转录是否可以通过Cdx 2表达来调节，Cdx 2是一种参与滋养外胚层细胞分化控制的转录因子。人绒毛膜癌JEG 3细胞用oIFN tau（~ 654碱基对，bp）-荧光素酶报告基因（~ 654-oIFN tau-Luc）构建体和几种转录因子表达质粒共转染。与单独的-654-oIFN tau-Luc相比，Cdx 2、Ets-2和c-jun共转染后，-654-oIFN tau-Luc的转录水平提高了30倍以上，当上游区减少到-551bp时，转录水平降低到原来的1/4，随着上游区的进一步缺失，转录水平降低到最低;这通过使用具有突变的c-jun、Ets-2和/或Cdx 2位点的报道构建体得到证实。在不支持IFN tau基因转录的滋养层无关的NIH 3 T3细胞中，当用Cdx 2/Ets-2或Cdx 2/Ets-2/c-jun表达质粒共转染细胞时，olFN tau-Luc转录增强约8倍。这些发现证实了凝胶迁移试验检查Cdx结合位点上的oIFN tau基因的上游区域，通过免疫组织化学研究确定Cdx 2的存在下，在第15和17天的绵羊受孕，并通过Western印迹检测Cdx 2在第17天的受孕。我们的研究结果表明，oIFN tau基因的转录受Cdx 2的调控，提示Cdx 2可能是决定滋养外胚层oIFN tau基因转录的关键分子。
Expression of ovine interferon-tau (oIFN tau), a factor essential for the process of maternal recognition of pregnancy in ruminant ungulates, is restricted to the trophoblast. However, the molecular mechanisms by which olFN tau expression is restricted to the trophectoderm have not been fully elucidated, The objective of this study was to determine whether oIFN tau gene transcription could be regulated through Cdx2 expression, a transcription factor implicated in the control of cell differentiation in the trophectoderm. Human choriocarcinoma JEG3 cells were co-transfected with an oIFN tau (-654 base pair, bp)-luciferase reporter (-654-oIFN tau-Luc) construct and several transcription factor expression plasmids. Compared to -654-oIFN tau-Luc alone, transcription of the -654oIFN tau-Luc increased more than 30 times when this construct was co-transfected with Cdx2, Ets-2, and c-jun. The degree of transcription decreased to 1/4 levels when the upstream region was reduced to -551 bp, and became minimal with further deletions; this was confirmed with the use of the reporter constructs with mutated c-jun, Ets-2, and/or Cdx2 sites. In trophoblast unrelated NIH3T3 cells, which do not support IFN tau gene transcription, the olFN tau-Luc transcription was enhanced approximately eightfold when the cells were co-transfected with the Cdx2/Ets-2 or Cdx2/Ets-2/c-jun expression plasmids. These findings were confirmed by gel-shift assays examining Cdx binding site on the oIFN tau gene's upstream region, by immunohistochemical study identifying the presence of Cdx2 in day 15 and 17 ovine conceptuses, and by Western blot detecting Cdx2 in day 17 conceptuses. Our results indicate that oIFN tau gene transcription is regulated by Cdx2, and suggest that Cdx2 could be a key molecule in determining oIFN tau gene transcription by the trophectoderm.