Genomic mapping of binding regions for the Ecdysone receptor protein complex
Genomic mapping of binding regions for the Ecdysone receptor protein complex
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DOI：
10.1101/gr.081349.108
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发表时间：
2009-06-01
期刊：
影响因子：
7
通讯作者：
White, Kevin P.
中科院分区：
文献类型：
--
作者：
Gauhar, Zareen;Sun, Ling V.;White, Kevin P.
我们利用一个对20-羟基蜕皮酮(20-HE)有反应而分化的细胞系(KC167)，确定了异二聚体蜕皮酮受体/超阿司匹林(ECR/USP)核激素受体复合体在整个非重复基因组中的物理位置。20-HE是该复合体的天然配体，控制昆虫发育的主要方面，包括蜕皮、变态和繁殖。结合物理结合位点图谱和20-HE处理后的基因表达谱鉴定了20-HE信号的直接基因靶点。我们在基因组中发现了502个ECR/USP结合的重要区域。这些区域中只有42%是在这些细胞中对20-HE有反应的邻近基因。然而，在变态过程中，至少四分之三的剩余ECR/USP区域在其他组织和细胞类型中接近20-HE调节的基因，这表明与基因组中许多调节元件的结合在很大程度上是非细胞类型特异性的。大多数(21/26)的20-HE早期靶点编码转录调控因子。为了确定这些细胞的形态分化是否需要这些靶点，我们使用RNAi来降低26个早期基因中的每一个的表达。因此，我们发现ECR/USP的三个直接靶点-毛发、Vrille和HR4-是细胞分化对激素的反应所必需的。Vrille在体内的初步突变分析表明，它是变形所必需的。
We determined the physical locations of the heterodimeric Ecdysone receptor/Ultraspiracle (ECR/USP) nuclear hormone receptor complex throughout the entire nonrepetitive genome of Drosophila melanogaster using a cell line (Kc167) that differentiates in response to 20-hydroxyecdysone (20-HE). 20-HE, the natural ligand of this complex, controls major aspects of insect development, including molting, metamorphosis, and reproduction. Direct gene targets of 20-HE signaling were identified by combining this physical binding-site profiling with gene expression profiling after treatment with 20-HE. We found 502 significant regions of ECR/USP binding throughout the genome. Only 42% of these regions are nearby genes that are 20-HE responsive in these cells. However, at least three quarters of the remaining ECR/USP regions are near 20-HE-regulated genes in other tissue and cell types during metamorphosis, suggesting that binding at many regulatory elements in the genome is largely noncell-type specific. The majority (21/26) of the early targets of 20-HE encode transcriptional regulatory factors. To determine whether any of these targets are required for the morphological differentiation of these cells, we used RNAi to reduce the expression of each of the 26 early genes. Accordingly, we found that three direct targets of ECR/USP-hairy, vrille, and Hr4-are required for cellular differentiation in response to the hormone. Initial mutational analysis of vrille in vivo reveals that it is required for metamorphosis.