Repression of Pax-2 by WT1 during normal kidney development.
Repression of Pax-2 by WT1 during normal kidney development.
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DOI：
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发表时间：
1995-03
期刊：
影响因子：
4.6
通讯作者：
G. Ryan;V. Steele-Perkins;J. Morris;F. Rauscher;G. Dressler
中科院分区：
文献类型：
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作者：
G. Ryan;V. Steele-Perkins;J. Morris;F. Rauscher;G. Dressler
发育调控基因Pax-2在早期肾脏形态发生过程中被激活，在成熟的肾上皮细胞中被抑制。在各种肾脏肿瘤中也观察到持续的Pax-2表达。然而，对于在发育中的肾脏中调节这种瞬时表达模式的信号知之甚少。我们用特异性抗体检测了Pax-2和Wilm‘s肿瘤抑制蛋白WT1在小鼠肾脏发育过程中的时空表达模式。WT1蛋白水平的显著升高恰好与内脏肾小球上皮单个前体细胞中Pax-2基因的下调相吻合，表明WT1抑制蛋白对Pax-2调节元件有直接影响。为了检测WT1是否能直接抑制Pax-2转录，DNAseI足迹分析表明WT1与5‘未翻译的Pax-2前导序列中的三个高亲和力位点结合。此外，在Pax-2调控序列控制下使用CAT报告构建的共转染分析显示WT1依赖的转录抑制。这三个WT1结合位点也能够以WT1依赖的方式抑制转录，当插入到异源启动子和报告基因之间时。这些数据表明，Pax-2可能是WT1的靶基因，并提示在转录调控水平上，活跃在未分化和增殖细胞中的发育控制基因与已知的肿瘤抑制基因之间存在直接联系。
The developmental, regulatory gene Pax-2 is activated during early kidney morphogenesis and repressed in mature renal epithelium. Persistent Pax-2 expression is also observed in a variety of kidney tumors. Yet, little is known about the signals regulating this transient expression pattern in the developing kidney. We have examined the spatial and temporal expression patterns of Pax-2 and the Wilm's tumor suppresser protein WT1 with specific antibodies in developing mouse kidneys. A marked increase in WT1 protein levels coincided precisely with down-regulation of the Pax-2 gene in the individual precursor cells of the visceral glomerular epithelium, suggesting a direct effect of the WT1 repressor protein on Pax-2 regulatory elements. To examine whether WT1 could directly repress Pax-2 transcription, binding of WT1 to three high affinity sites in the 5' untranslated Pax-2 leader sequence was demonstrated by DNAseI footprinting analysis. Furthermore, co-transfection assays using CAT reporter constructs under the control of Pax-2 regulatory sequences demonstrated WT1-dependent transcriptional repression. These three WT1 binding sites were also able to repress transcription, in a WT1-dependent manner, when inserted between a heterologous promoter and the reporter gene. The data indicate that Pax-2 is a likely target gene for WT1 and suggest a direct link, at the level of transcriptional regulation, between a developmental control gene, active in undifferentiated and proliferating cells, and a known tumor suppressor gene.