Institute for the Advanced Study of Human Biology (WPI-ASHBi), Kyoto University, Kyoto, Japan.
Dev Growth Differ. 2020 Oct;62(7-8):465-475. doi: 10.1111/dgd.12690. Epub 2020 Aug 27.
The genome of many organisms contains several loci consisting of duplicated genes that are arrayed in tandem. The daughter genes produced by duplication typically exhibit differential expression patterns with each other or otherwise experience pseudogenization. Remarkably, opsin genes in fish are preserved after many duplications in different lineages. This fact indicates that fish opsin genes are characterized by a regulatory mechanism that could intrinsically facilitate the differentiation of the expression patterns. However, little is known about the mechanisms that underlie the differential expression patterns or how they were established during evolution. The loci of green (RH2)- and red (LWS)-sensitive cone opsin genes in zebrafish have been used as model systems to study the differential regulation of tandemly arrayed opsin genes. Over a decade of studies have uncovered several mechanistic features that might have assisted the differentiation and preservation of duplicated genes. Furthermore, recent progress in the understanding of the transcriptional process in general has added essential insights. In this article, the current understanding of the transcriptional regulation of differentially expressed tandemly arrayed cone opsin genes in zebrafish is summarized and a possible evolutionary scenario that could achieve this differentiation is discussed.
许多生物体的基因组包含几个由串联排列的重复基因组成的基因座。复制产生的子基因通常彼此表现出不同的表达模式，或者经历假基因化。值得注意的是，鱼类中的视蛋白基因在不同谱系的多次复制后得以保留。这一事实表明，鱼类视蛋白基因具有一种调控机制，可以内在地上调表达模式的分化。然而，对于导致这些表达模式差异的机制，以及它们在进化过程中是如何建立的，我们知之甚少。斑马鱼中绿色（RH2）和红色（LWS）敏感视锥蛋白基因的基因座已被用作研究串联排列视蛋白基因差异调控的模型系统。十多年的研究揭示了几种可能有助于重复基因分化和保留的机制特征。此外，对转录过程的理解在近年来也取得了重要进展。本文总结了斑马鱼中差异表达的串联排列视锥蛋白基因的转录调控的最新认识，并讨论了可能实现这种分化的进化情景。
