Prostaglandin H synthase-2 gene regulation in the amnion at labour:: histone acetylation and nuclear factor kappa B binding to the promoter in vivo
Prostaglandin H synthase-2 gene regulation in the amnion at labour:: histone acetylation and nuclear factor kappa B binding to the promoter in vivo
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DOI：
10.1093/molehr/gam086
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发表时间：
2008-01-01
影响因子：
4
通讯作者：
Zakar, T.
中科院分区：
文献类型：
--
作者：
Mitchell, C. M.;Johnson, R. F.;Zakar, T.
羊膜中前列腺素H合酶-2（PGHS-2）表达的增加对于诱导分娩的前列腺素的产生至关重要。本研究的目的是确定PGHS-2基因的活性是否是由NF κ B B转录因子在体内足月羊膜中控制的体外研究结果所建议的。选择性剖腹产术（n = 14）或自然分娩（n = 12）后收集羊膜足月，组蛋白乙酰化和转录因子结合PGHS-2和I κ B α启动子在新鲜组织中染色质免疫沉淀法测定。在PGHS-2启动子近端1000 bp区域检测到高水平的组蛋白-3和-4乙酰化，表明在含有两个共有NF κ B结合位点和其他转录因子结合基序的区域中存在允许的染色质结构。TATA盒被TATA结合蛋白（TBP）占据，表明PGHS-2基因在分娩前后都具有转录活性。NF κ B（p65和p50）结合的共识网站，然而，只检测到之前，但没有后，劳动。此外，在相同组织中，分娩前NF κ B因子结合与TBP结合PGHS-2 TATA盒无关。此外，p65与NF κ B反应性I κ B α启动子的结合在分娩时增加，并且与TBP与该基因的TATA盒的结合强烈相关。我们的结论是，近端1000 bp的区域参与PGHS-2启动子调控在足月羊膜。NF κ B系统在分娩时被激活并刺激I κ B α基因，但NF κ B因子在体内正常足月羊膜中不使用共有启动子位点驱动PGHS-2转录。
Increased prostaglandin H synthase-2 (PGHS-2) expression in the amnion is critical for the production of prostaglandins that induce labour. The aim of the present investigation was to determine whether PGHS-2 gene activity is controlled by NF kappa B transcription factors in term amnion in vivo as suggested by in vitro findings. Amnion membranes were collected after elective Caesarean section (n = 14) or spontaneous labour (n = 12) at term, and histone acetylation and transcription factor binding to the PGHS-2 and I kappa B alpha promoters were determined in fresh tissues by chromatin immunoprecipitation. High level of histone-3 and -4 acetylation was detected in the proximal 1000 bp region of the PGHS-2 promoter indicating permissive chromatin structure in an area that contains two consensus NF kappa B binding sites and other transcription factor binding motifs. The TATA-box was occupied by TATA-binding protein (TBP) demonstrating that the PGHS-2 gene was transcriptionally active before and after labour. NF kappa B (p65 and p50) binding to the consensus sites, however, was detected only before, but not after, labour. Moreover, NF kappa B factor binding before labour was unrelated to TBP binding to the PGHS-2 TATA-box in the same tissues. Further, p65 binding to the NF kappa B-responsive I kappa B alpha promoter increased at labour and correlated strongly with TBP binding to the TATA-box of this gene. We conclude that the proximal 1000 bp region is involved in PGHS-2 promoter regulation in term amnion. The NF kappa B system is activated at labour and stimulates the I kappa B alpha gene, but the NF kappa B factors do not drive PGHS-2 transcription using consensus promoter sites in normal term amnion in vivo.