Sharma S, Jhala U S, Johnson T, Ferreri K, Leonard J, Montminy M
Department of Biology, University of California, San Diego, La Jolla 92037, USA.
Mol Cell Biol. 1997 May;17(5):2598-604. doi: 10.1128/MCB.17.5.2598.
The homeobox protein STF-1 appears to function as a master control switch for expression of the pancreatic program during development. Here we characterize a composite enhancer which directs STF-1 expression to pancreatic islet cells via two functional elements that recognize the nuclear factors HNF-3beta and BETA-2. In keeping with their inhibitory effects on islet cell maturation, glucocorticoids were found to repress STF-1 gene expression by interfering with HNF-3beta activity on the islet-specific enhancer. Overexpression of HNF-3beta suppressed glucocorticoid receptor-mediated inhibition of the STF-1 gene, and our results suggest that the expansion of pancreatic islet precursor cells during development may be restricted by hormonal cues which regulate STF-1 gene expression.
同源框蛋白STF-1在发育过程中似乎起着胰腺程序表达主控制开关的作用。在此,我们鉴定了一个复合增强子,它通过识别核因子HNF-3β和BETA-2的两个功能元件将STF-1表达导向胰岛细胞。鉴于糖皮质激素对胰岛细胞成熟的抑制作用,发现其通过干扰HNF-3β在胰岛特异性增强子上的活性来抑制STF-1基因表达。HNF-3β的过表达抑制了糖皮质激素受体介导的STF-1基因抑制作用,我们的结果表明,发育过程中胰岛前体细胞的扩增可能受到调节STF-1基因表达的激素信号的限制。