PDF(Pubmed)
Abstract：
Transcription factor Ap2b (TFAP2B), an AP-2 family transcription factor, binds to the palindromic consensus DNA sequence, 5\'-GCCN3-5GGC-3\'. Mice lacking functional Tfap2b gene die in the perinatal or neonatal period with cystic dilatation of the kidney distal tubules and collecting ducts, a phenotype resembling autosomal recessive polycystic kidney disease (ARPKD). Human ARPKD is caused by mutations in PKHD1, DZIP1L, and CYS1, which are conserved in mammals. In this study, we examined the potential role of TFAP2B as a common regulator of Pkhd1 and Cys1. We determined the transcription start site (TSS) of Cys1 using 5\' Rapid Amplification of cDNA Ends (5\'RACE); the TSS of Pkhd1 has been previously established. Bioinformatic approaches identified cis-regulatory elements, including two TFAP2B consensus binding sites, in the upstream regulatory regions of both Pkhd1 and Cys1. Based on reporter gene assays performed in mouse renal collecting duct cells (mIMCD-3), TFAP2B activated the Pkhd1 and Cys1 promoters and electromobility shift assay (EMSA) confirmed TFAP2B binding to the in silico identified sites. These results suggest that Tfap2b participates in a renal epithelial cell gene regulatory network that includes Pkhd1 and Cys1. Disruption of this network impairs renal tubular differentiation, causing ductal dilatation that is the hallmark of recessive PKD.
摘要：
转录因子Ap2b(TFAP2B),AP-2家族转录因子，结合回文共有DNA序列，5'-GCCN3-5GGC-3'。缺乏功能性Tfap2b基因的小鼠在围产期或新生儿期死亡，肾脏远端小管和集合管的囊性扩张，一种类似常染色体隐性遗传性多囊肾病(ARPKD)的表型。人类ARPKD是由PKHD1，DZIP1L，和CYS1，它们在哺乳动物中是保守的。在这项研究中,我们研究了TFAP2B作为Pkhd1和Cys1共同调节因子的潜在作用。我们使用5'cDNA末端快速扩增（5'RACE）确定了Cys1的转录起始位点（TSS）；Pkhd1的TSS已经建立。生物信息学方法确定了顺式调控元件，包括两个TFAP2B共有结合位点，在Pkhd1和Cys1的上游调节区域。基于在小鼠肾集合管细胞（mIMCD-3）中进行的报告基因测定，TFAP2B激活了Pkhd1和Cys1启动子，电迁移变化测定（EMSA）证实了TFAP2B与计算机鉴定的位点的结合。这些结果表明Tfap2b参与了包括Pkhd1和Cys1的肾上皮细胞基因调控网络。该网络的破坏损害肾小管分化，引起导管扩张，这是隐性PKD的标志。
