van der Sluis Maria, Vincent Audrey, Bouma Janneke, Korteland-Van Male Anita, van Goudoever Johannes B, Renes Ingrid B, Van Seuningen Isabelle
Department of Paediatrics, Division of Neonatology, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands.
Biochem Biophys Res Commun. 2008 May 16;369(4):1108-13. doi: 10.1016/j.bbrc.2008.02.158. Epub 2008 Mar 10.
The mucin Muc2 is the main component of the intestinal mucus layer and thus plays important roles in intestinal protection. Therefore, it is important to understand its regulation during goblet cell differentiation. Foxa1 and Foxa2 forkhead box transcription factors (TFs) participate in transcriptional programs governing intestinal cell differentiation. Using immunohistochemistry, we showed a spatio-temporal pattern of expression of both TFs in developing and adult mouse intestine and their expression in Muc2-expressing intestinal cells. Down-regulation of Foxa1 and Foxa2 by RNA interference in cultured intestinal cells decreased Muc2 mRNA level by half, and abolished Muc2 protein expression. Chromatin immunoprecipitation and gel shift assays showed that these two TFs directly bind to the Muc2 promoter. Co-transfection experiments indicated that both TFs activate the Muc2 promoter and that mutations of three Foxa cis-elements inhibit Muc2 transactivation. In conclusion, this work identifies Foxa1 and Foxa2 as important regulators of Muc2 expression in the intestine.
粘蛋白Muc2是肠道粘液层的主要成分，因此在肠道保护中发挥着重要作用。所以，了解其在杯状细胞分化过程中的调控机制很重要。Foxa1和Foxa2叉头框转录因子（TFs）参与调控肠道细胞分化的转录程序。通过免疫组织化学，我们展示了这两种转录因子在发育中和成年小鼠肠道中的时空表达模式以及它们在表达Muc2的肠道细胞中的表达情况。在培养的肠道细胞中通过RNA干扰下调Foxa1和Foxa2，可使Muc2 mRNA水平降低一半，并消除Muc2蛋白表达。染色质免疫沉淀和凝胶迁移实验表明，这两种转录因子直接结合到Muc2启动子上。共转染实验表明，这两种转录因子均可激活Muc2启动子，并且三个Foxa顺式元件的突变会抑制Muc2的反式激活。总之，这项研究确定Foxa1和Foxa2是肠道中Muc2表达的重要调节因子。
