Transcription profiling of mouse GATA4 conditional knockout small intestine

Background and Aims: Although the zinc finger transcription factor GATA4 has been implicated in regulating jejunal gene expression, the contribution of GATA4 in controlling jejunal physiology has not been addressed. Methods: We generated mice in which the Gata4 gene was specifically deleted in the small intestinal epithelium. Measurements of plasma cholesterol and phospholipids, intestinal absorption of dietary fat and cholesterol, and gene expression were performed on these animals. Results: Mice lacking GATA4 in the intestine displayed a dramatic block in their ability to absorb cholesterol and dietary fat. Comparison of the global gene expression profiles of control jejunum, control ileum, and GATA4 null jejunum by gene array analysis demonstrated that GATA4 null jejunum lost expression of 53% of the jejunal-specific gene set and gained expression of 47% of the set of genes unique to the ileum. These alterations in gene expression included a decrease in mRNAs encoding lipid and cholesterol transporters as well as an increase in mRNAs encoding proteins involved in bile acid absorption. Conclusion: Our data demonstrate that GATA4 is essential for jejunal function including fat and cholesterol absorption and confirm that GATA4 plays a pivotal role in determining jejunal versus ileal identity. Experiment Overall Design: Total RNA was harvested from the following sources and used to Affymetrix array analysis following manufacturer defined protocols: Experiment Overall Design: control jejunum (Gata4loxP/+VilCre), 3 male mice, adult (6-8 wk) Experiment Overall Design: mutant jejunum (Gata4loxP/-VilCre), 3 male mice, adult (6-8 wk) Experiment Overall Design: control ileum (Gata4loxP/+VilCre), 3 male mice, adult (6-8 wk). Experiment Overall Design: A total of nine Mouse Genome 430_2.0 arrays were hybridized for this study. Experiment Overall Design: Jejunum was defined as 10 cm from the pyloric sphincter, and ileum was defined as 1 cm from the cecum. The animals used to harvest control jejunum and ileum were independent of each other.背景与研究目的：尽管锌指转录因子GATA4（zinc finger transcription factor GATA4）已被证实可调控空肠基因的表达，但GATA4在控制空肠生理功能中的具体作用尚未得到明确阐释。 研究方法：本研究构建了在小肠上皮细胞中特异性敲除Gata4基因的小鼠模型。随后对该模型小鼠开展血浆胆固醇与磷脂水平检测、膳食脂肪及胆固醇的肠道吸收实验，以及基因表达分析。 实验结果：肠道缺失GATA4的小鼠，其胆固醇与膳食脂肪的吸收能力出现显著阻断。通过基因芯片分析对比对照组空肠、对照组回肠以及GATA4敲除空肠的全局基因表达谱，结果显示GATA4敲除的空肠丧失了53%的空肠特异性基因表达集，同时获得了47%的回肠特异性基因表达集。此类基因表达改变包括脂质与胆固醇转运蛋白编码信使RNA（mRNA）的下调，以及胆汁酸吸收相关蛋白编码mRNA的上调。 研究结论：本研究数据证实，GATA4对于空肠的脂肪与胆固醇吸收等生理功能至关重要，并确认GATA4在决定空肠与回肠的细胞身份中发挥关键作用。 实验整体设计：本研究从以下样本中提取总RNA，并按照制造商指定的实验方案开展Affymetrix基因芯片分析： 1. 对照组空肠（Gata4loxP/+VilCre）：3只成年雄性小鼠，周龄6-8周； 2. 突变体空肠（Gata4loxP/-VilCre）：3只成年雄性小鼠，周龄6-8周； 3. 对照组回肠（Gata4loxP/+VilCre）：3只成年雄性小鼠，周龄6-8周。 本研究共使用9张小鼠基因组430_2.0基因芯片进行杂交实验。本实验中，空肠定义为距幽门括约肌10cm的肠段，回肠定义为距盲肠1cm的肠段。用于提取对照组空肠与回肠RNA的实验动物为相互独立的个体。