Identification of Reverbα as a novel RORα target gene
Identification of Reverbα as a novel RORα target gene
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DOI：
10.1074/jbc.m202979200
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发表时间：
2002-09-20
影响因子：
4.8
通讯作者：
Suen, CS
中科院分区：
文献类型：
--
作者：
Delerive, P;Chin, WW;Suen, CS
核受体超家族包含大量配体激活的转录因子，其参与许多生物过程，如细胞增殖、分化和稳态。RORalpha（NR 1F 1）和Reverbalpha（NR 1D 1）是该家族的两个成员，其生物学功能在很大程度上是未知的。此外，尚未鉴定出这两种受体的配体;因此，它们被称为孤儿受体。在这里，我们表明，RORalpha和Reverbalpha表达具有相似的组织分布，都诱导大鼠L 6成肌细胞分化过程中。通过北方印迹分析证实，RORalpha 1在L 6细胞中的异位表达显著诱导Reverbalpha表达。采用逆转录-PCR技术分析了蹒跚小鼠的Reverbalpha基因表达，发现与野生型小鼠相比，蹒跚小鼠骨骼肌中Reverbalpha mRNA的表达显著减少，提示RORalpha参与了Reverbalpha基因表达的调控。使用Reverbalpha启动子的瞬时转染测定证明RORa在转录水平上调节Reverbalpha基因。此外，诱变实验表明，ROR α通过位于Reverbalpha基因启动子中的单体ROR响应元件调节Reverbalpha转录。电泳迁移率变动分析表明ROR α以特异性方式与该位点强烈结合。最后，在瞬时转染实验中，GRIP-1/TIF-2而不是SRC-1的过表达增强了RORa刺激的Reverbalpha启动子活性。总之，我们的研究结果确定Reverbalpha作为RORalpha的新靶基因。
The nuclear receptor superfamily comprises a large number of ligand-activated transcription factors that are involved in numerous biological processes such as cell proliferation, differentiation, and homeostasis. RORalpha (NR1F1) and Reverbalpha (NR1D1) are two members of this family whose biological functions are largely unknown. In addition, no ligand has been yet identified for these two receptors; therefore, they are referred as orphan receptors. Here, we show that RORalpha and Reverbalpha are expressed with a similar tissue distribution and are both induced during the differentiation of rat L6 myoblastic cells. Ectopic expression of RORalpha1 in L6 cells significantly induces Reverbalpha expression as demonstrated by Northern blot analysis. Using reverse transcription-PCR to analyze Reverbalpha gene expression from staggerer mice, we found that there was a significant reduction of Reverbalpha mRNA in the skeletal muscle comparing it with the wild-type mice, which suggests that RORalpha is involved in the regulation of Reverbalpha gene expression. Transient transfection assays using the Reverbalpha promoter demonstrate that RORalpha regulates the Reverbalpha gene at the transcriptional level. Furthermore, mutagenesis experiments indicate that RORalpha regulates Reverbalpha transcription via a monomeric ROR response element located in the Reverbalpha gene promoter. Electrophoretic mobility shift assays show that RORalpha binds strongly to this site in a specific-manner. Finally, overexpression of GRIP-1/TIF-2, but not SRC-1, potentiates RORalpha-stimulated Reverbalpha promoter activity in transient transfection experiments. Together, our results identify Reverbalpha as a novel target gene for RORalpha.