Yamamoto Hiroshi, Bai Yun Qing, Yuasa Yasuhito
Department of Molecular Oncology, Graduate School of Medicine and Dentistry, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
Biochem Biophys Res Commun. 2003 Jan 24;300(4):813-8. doi: 10.1016/s0006-291x(02)02935-2.
Intestinal mucin gene MUC2 is abundantly expressed in goblet cells. To identify the transcriptional activator that regulates goblet-specific expression of MUC2, we analyzed the interaction between the MUC2 promoter and homeodomain proteins CDX1/2, which are involved in the regulation of intestinal development and differentiation. COS-7 cells were transiently transfected with a CDX1 or CDX2 expression construct and then used for the luciferase assay, reverse transcription-polymerase chain reaction, and electrophoretic mobility shift assay (EMSA). The CDX2 expression construct activated the MUC2 promoter and increased the endogenous MUC2 mRNA level, while the CDX1 one did not. EMSA revealed that CDX2 bound to the MUC2 gene cis element, MUC2-WT. These results suggest that CDX2, but not CDX1, interacts with the MUC2 promoter and activates MUC2 transcription, and plays an important role in the differentiation of goblet cells.
肠道粘蛋白基因MUC2在杯状细胞中大量表达。为了鉴定调节MUC2杯状细胞特异性表达的转录激活因子，我们分析了MUC2启动子与参与肠道发育和分化调节的同源结构域蛋白CDX1/2之间的相互作用。用CDX1或CDX2表达构建体瞬时转染COS-7细胞，然后用于荧光素酶测定、逆转录-聚合酶链反应和电泳迁移率变动分析（EMSA）。CDX2表达构建体激活了MUC2启动子并提高了内源性MUC2 mRNA水平，而CDX1表达构建体则没有。EMSA显示CDX2与MUC2基因顺式元件MUC2-WT结合。这些结果表明，CDX2而非CDX1与MUC2启动子相互作用并激活MUC2转录，在杯状细胞分化中起重要作用。
