Expression Profiling Identifies Novel Gene Targets and Functions for Pdx1 in the Duodenum of Mature Mice

Transcription factor pancreatic and duodenal homeobox 1 (Pdx1) plays an essential role in the pancreas to regulate its development and maintain proper islet function. However, less is known about the function of Pdx1 in the small intestine. We aim to investigate the role of Pdx1 in mature proximal small intestine by profiling the expression of genes differentially regulated in response to Pdx1 inactivation restricted to the intestinal epithelium in mice. Pdx1 was conditionally inactivated in the intestinal epithelium of Pdx1flox/flox;VilCre mice, by crossing mutant mice homozygous for loxP site-flanked Pdx1 alleles with transgenic mice expressing Cre recombinase under the control of the mouse villin 1 gene promoter. Total RNA was isolated from the first five centimeters of the small intestine from adult Pdx1flox/flox;VilCre and littermate control mice. Microarray analysis was performed to investigate genome-wide transcriptional profiles in the proximal small intestine.转录因子胰腺十二指肠同源框1（Pdx1）在胰腺发育调控与胰岛功能维持中发挥核心作用。然而，目前学界对Pdx1在小肠中的功能尚缺乏深入认知。本研究旨在通过分析小鼠肠道上皮特异性Pdx1失活后差异表达的基因，探究Pdx1在成熟近端小肠中的调控作用。将携带两侧锚定loxP位点的Pdx1等位基因的纯合突变小鼠，与在小鼠绒毛蛋白1（villin 1）基因启动子调控下表达Cre重组酶（Cre recombinase）的转基因小鼠进行杂交，从而在Pdx1flox/flox;VilCre小鼠的肠道上皮中实现Pdx1的条件性失活。随后从成年Pdx1flox/flox;VilCre小鼠及其同窝对照小鼠的小肠前5厘米区段提取总RNA，通过基因芯片（Microarray）分析检测近端小肠的全基因组转录谱。