Characterization of the rat intestinal Fc receptor (FcRn) promoter: transcriptional regulation of FcRn gene by the Sp family of transcription factors.
Characterization of the rat intestinal Fc receptor (FcRn) promoter: transcriptional regulation of FcRn gene by the Sp family of transcription factors.
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DOI：
10.1152/ajpgi.00131.2003
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发表时间：
2004-06
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通讯作者：
Lingling Jiang;Jiafang Wang;R. Solórzano-Vargas;H. V. Tsai;E. M. Gutierrez;Luis O Ontiveros;P. Kiela;S. Wu;Martín G. Martín-Martín-G.-Martín-2219810849
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文献类型：
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作者：
Lingling Jiang;Jiafang Wang;R. Solórzano-Vargas;H. V. Tsai;E. M. Gutierrez;Luis O Ontiveros;P. Kiela;S. Wu;Martín G. Martín-Martín-G.-Martín-2219810849
控制肠Fc受体（FcRn）转录调控的调控元件尚未阐明。本研究的目的是表征大鼠FcRn基因的核心启动子区。将含有位于荧光素酶报告基因上游的启动子的各个区域的嵌合克隆瞬时转染到IEC-6或Caco-2细胞系中，并使用核提取物进行DNA酶I足迹和DNA结合测定（EMSA）。将嵌合上游巢式缺失-荧光素酶报告基因克隆转染到这些细胞系中的任一种中支持稳健的报告基因活性，并鉴定了最小启动子在-157/+135的位置。DNA酶I足迹分析揭示了位于基因的核心启动子区域内的两个复合物，并且定点诱变确定了对维持基础表达至关重要的两个区域。EMSA鉴定出在直接启动子区域内存在5个Sp元件，其能够结合Sp蛋白家族的成员。在五个Sp元件中，一个元件似乎不结合Sp1、Sp2或Sp3，同时影响Sp蛋白与相邻Sp位点的相互作用。Sp1或Sp3的过表达增强了SP缺陷型果蝇SL 2细胞中最小启动子的活性。总之，我们报告大鼠FcRn最小启动子的表征，包括该区域内的5个Sp元件的表征，这些元件与Sp家族的转录因子的成员相互作用，并驱动肠细胞系中的启动子活性。
The regulatory elements that control the transcriptional regulation of the intestinal Fc receptor (FcRn) have not been elucidated. The objective of this study was to characterize the core promoter region of the rat FcRn gene. Chimeric clones that contained various regions of the promoter located upstream of the luciferase reporter were transiently transfected into either IEC-6 or Caco-2 cell lines and nuclear extracts were used to perform DNase I footprint and DNA binding assays (EMSA). Transfection of chimeric upstream nested deletions-luciferase reporter clones into either of these cell lines supported robust reporter activity and identified the location of the minimal promoter at -157/+135. DNase I footprint analysis revealed two complexes located within the gene's core promoter region, and site-directed mutagenesis identified two regions that were critical to maintain basal expression. EMSA identified the presence of five Sp elements within the immediate promoter region that are capable of binding members of the Sp family of proteins. Among the five Sp elements, one element appears to not bind Sp1, Sp2, or Sp3 while influencing the interaction of Sp proteins with an adjacent Sp site. Overexpression of either Sp1 or Sp3 augments activity of the minimal promoter in Sp-deficient Drosophila SL2 cells. In summary, we report on the characterization of the rat FcRn minimal promoter, including the characterization of five Sp elements within this region that interact with members of the Sp family of transcriptional factors and drive promoter activity in intestinal cell lines.