Transcriptional regulation of kidney-specific genes

水通道蛋白-2(Aquaporin-2，AQP2)的表达仅限于肾脏集合管细胞，这种严格受限的表达可能通过该基因的转录来调节。AQP2基因的5-侧翼区由一个TATA盒、两个GATA共有序列、一个AP-1位点、一个AP-2位点、三个E盒和一个周期AMP反应元件组成。在IMCD细胞原代培养的第1天进行的报告基因分析表明，高达-2.9kb的5‘端是一个启动子。缺失实验表明，至少有两个区域，从-434到-364和从-153到-84，含有负性作用的顺式元件。为了研究GATA基序在AQP2基因中的功能作用，我们试图分离在集合管中表达的GATA因子(S)。从大鼠肾脏中分离到两个编码GATA因子的cDNA(GATA-2和GATA-3)。AQP2基因5-侧翼区的GATA基序是功能顺式元件，集合管中的GATA-3可能是…的重要调节因子之一大鼠CIC-K1氯通道是010氯通道家族中的一个肾脏特异性成员，专门发现于肾脏Henle‘s环的IF-In上升支中。为了深入了解CIC-K1基因肾脏特异性表达的机制(S)，我们分离了一个含有大鼠CIC-K1基因5‘侧翼区的基因组DO。缺失分析表明，在IM细胞中，这种细胞特异性启动子活性仍然存在于含有51bp的5‘侧翼区的结构中，但在-29结构中缺失，这充分证明了在CIC-K1启动子的细胞特异性活性中，-51~-30的-22个碱基对细胞特异性活性起主要作用。凝胶滞留分析表明，IM细胞中存在一个与该元件结合的特异性蛋白(S)。这些结果表明，新的富嘌呤元件可能在CIC-K1基因启动子的活性中起关键作用。较少

Expression of aquaporin-2 (AQP2) is exclusively limited to kidney collecting duct cells, and this strictly limited expression could be mediated by transcription of the gene. The 5-flanking region of the AQP2 gene was characterized by a TATA box, two GATA consensus sequences, an AP-1 site, an AP-2 site, three E-boxes, and a cycle AMP-responsive element. A reporter gene assay performed in the 1st day of primary culture of IMCD cells showed that the 5' region up to -2.9 kb worked as a promoter. Deletion experiments showed that at least two regions, from -434 to -364 and from -153 to -84, contain negatively acting cis-elements. To evaluate the functional role of GATA motifs in AQP2 gene, we sought to isolate a GATA factor(s) expressed in collecting ducts. Two cDNAs encoding GATA factors were isolated from rat kidney (GATA-2 and -3). GATA motifs in the 5-flanking region of the AQP2 gene were functional cis-elements and that GATA-3 in collecting ducts may be one of the important regulators o … More f AQP-2 expression in vivo.The rat CIC-K1 chloride channel is a kidney-specific member of the 010 chloride channel family found exclusively in the if-in ascending limb of Henle's loop in the kidney. To gain insight into the mechanism(s) of kidney-specific expression of CIC-K1, a genomic done that contains the 5'-flanking region of the rat CIC-K1 gene was isolated. The sequence of the proximal 5-flanking region contained an AP-3 site, a GRE, several AP-2 sites, and several E-boxes, but it lacked a TATA box.Deletion analysis revealed that this cell-specific promoter activity in IM cells was still present in the construct containing 51 b p of-the 5'-flanking region but was lost in the -29 construct, dearly demonstrating that the-22 bp from -51 to -30 have a major role in the cell-specific activity of the CIC-K1-promoter. These 22 bp consist of purine-rich sequence (GGGGAGGGG-GAGGGGAG), and gel-retardation analysis demonstrated the existence of a specific protein(s) binding to this element in IM cells. These results suggest that the novel purine-rich element may play a key role in the activity of the CIC-K1 gene promoter. Less