The emergence of a transcriptional silencer underlying the loss of a morphological trait

转录沉默子的出现导致形态特征的丧失

• 批准号: 491842640
• 负责人: Professor Dr. Nicolas Gompel
• 金额: --
• 依托单位: Abteilung III: Evolutionsbiologie und Ökologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/491842640?language=en
• 关键词: emergence; transcriptional; silencer; underlying; loss

Morphological diversity and the variation in discrete traits that composes it result, to a large extent, from changes in the regulation of developmental genes. Notably, variation in the regulatory sequences of these genes fuels evolutionary changes in gene expression. Transcriptional enhancers in particular respond to specific transcription factors and determine when, where and how much developmental genes are transcribed. The main focus in the evolutionary literature to explain the variation of enhancer activities is the turnover of binding sites for these transcription factors. It was recently suggested, however, that the accessibility of enhancer sequences, determined by the degree of chromatin compaction, may also explain the variation of enhancer activities and thereby modulate gene expression. Yet, this regulatory level, chromatin accessibility, has not been examined from this evolutionary standpoint. The present proposal attempts to bridge this gap by studying the role of chromatin accessibility in the evolution of a discrete morphological character, a pigmentation spot at the tip of the wing in flies (Drosophila). Namely, we have identify intriguing changes in the accessibility in the regulatory regions of the pigmentation gene yellow, between a spotted species and a species that has secondarily lost its spot. Yellow expression underlies the formation of the spot, and variation in its expression represent an important evolutionary node explaining wing pigmentation diversity. Combining reporter assays in transgenic Drosophila and genomic profiling (ATAC-seq, ChiP-seq) of these regions, we will decipher by which molecular mechanisms changes of chromatin accessibility may have modulated the expression of a gene during an evolutionary transition.

形态多样性和组成它的离散性状的变化在很大程度上源于发育基因调控的变化。值得注意的是，这些基因的调控序列的变化促进了基因表达的进化变化。转录增强子特别对特定的转录因子作出反应，并决定何时、何地以及转录多少发育基因。在解释增强子活性变化的进化文献中，主要关注的是这些转录因子结合位点的周转。然而，最近有人提出，由染色质压实程度决定的增强子序列的可及性也可能解释增强子活性的变化，从而调节基因表达。然而，这个调控水平，染色质可及性，还没有从进化的角度来研究。目前的建议试图通过研究染色质可及性在一个离散形态特征的进化中的作用来弥合这一差距，即果蝇翅膀尖端的色素沉着点。也就是说，我们已经确定了色素沉着基因黄色调控区域的可及性的有趣变化，在有斑点的物种和二次失去斑点的物种之间。黄色的表达是斑点形成的基础，其表达的变化是解释翅膀色素沉着多样性的重要进化节点。结合转基因果蝇的报告基因分析和这些区域的基因组分析（ATAC-seq, ChiP-seq），我们将破译在进化过渡过程中染色质可及性的变化可能调节基因表达的分子机制。