Genomic regulatory blocks underlie extensive microsynteny conservation in insects
Genomic regulatory blocks underlie extensive microsynteny conservation in insects
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DOI：
10.1101/gr.6669607
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发表时间：
2007-12-01
期刊：
影响因子：
7
通讯作者：
Lenhard, Boris
中科院分区：
文献类型：
--
作者：
Engstrom, Par G.;Sui, Shannan J. Ho;Lenhard, Boris
昆虫基因组含有比在染色体演化的随机破裂模型下预期的更大的保守基因顺序块（微生物）。我们提供的证据表明，已经保留了微生物，以保持大量高度保守的非编码元素（HCNES）完整。这些阵列涵盖了关键的发育调节基因，形成了基因组调节块（GRB）。我们最近描述了脊椎动物中的GRB，其中大多数HCNE作为增强剂，HCNE阵列指定其目标基因的复杂表达程序。在这里，我们对五个果蝇基因组进行了比较，表明HCNE密度在包含多个基因的大型同步块中集中峰值。除了可能是HCNE增强子靶标的发育调节剂外，HCNE阵列还经常跨越无关的相邻基因。我们描述了目标基因与无关基因之间的核心启动子的差异，这些基因为增强子的响应能力差异提供了解释。我们展示了同步块，HCNE阵列和PolyComb结合区域之间的醒目对应关系的示例，证实了同步块对应于调节域。 Although few noncoding elements are highly conserved between Drosophila and the malaria mosquito Anopheles gambiae, we find that A. gambiae regions orthologous to Drosophila GRBs contain an equivalent distribution of noncoding elements highly conserved in the yellow fever mosquito Aedes aegypti and coincide with regions of ancient microsynteny在果蝇和蚊子之间。昆虫和脊椎动物GRB之间的结构和功能等效性标志着它们是后生基因组的古老特征，也是对发展和基因调节的未来研究的关键。
Insect genomes contain larger blocks of conserved gene order (microsynteny) than would be expected under a random breakage model of chromosome evolution. We present evidence that microsynteny has been retained to keep large arrays of highly conserved noncoding elements (HCNEs) intact. These arrays span key developmental regulatory genes, forming genomic regulatory blocks ( GRBs). We recently described GRBs in vertebrates, where most HCNEs function as enhancers and HCNE arrays specify complex expression programs of their target genes. Here we present a comparison of five Drosophila genomes showing that HCNE density peaks centrally in large synteny blocks containing multiple genes. Besides developmental regulators that are likely targets of HCNE enhancers, HCNE arrays often span unrelated neighboring genes. We describe differences in core promoters between the target genes and the unrelated genes that offer an explanation for the differences in their responsiveness to enhancers. We show examples of a striking correspondence between boundaries of synteny blocks, HCNE arrays, and Polycomb binding regions, confirming that the synteny blocks correspond to regulatory domains. Although few noncoding elements are highly conserved between Drosophila and the malaria mosquito Anopheles gambiae, we find that A. gambiae regions orthologous to Drosophila GRBs contain an equivalent distribution of noncoding elements highly conserved in the yellow fever mosquito Aedes aegypti and coincide with regions of ancient microsynteny between Drosophila and mosquitoes. The structural and functional equivalence between insect and vertebrate GRBs marks them as an ancient feature of metazoan genomes and as a key to future studies of development and gene regulation.