Explosive lineage-specific expansion of the orphan nuclear receptor HNF4 in nematodes
Explosive lineage-specific expansion of the orphan nuclear receptor HNF4 in nematodes
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DOI：
10.1007/s00239-004-0175-8
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发表时间：
2005-05-01
影响因子：
3.9
通讯作者：
Sluder, A
中科院分区：
文献类型：
--
作者：
Robinson-Rechavi, M;Maina, CV;Sluder, A
核受体超家族至少经历了两次扩张：一次是在后生动物进化的早期，第二次是在脊椎动物谱系中。这种模式的一个例外是线虫线虫的基因组，它编码270多个核受体，其中大多数是高度分化的。共获得76个C基因的128个cDNA序列。elegans核受体，证实这些是活跃的基因。在这些众多的受体中，有13种是在节肢动物和/或脊椎动物中发现的核受体的直系同源物。我们发现，补充核受体（supnrs）起源于一个独特的孤儿受体，HNF 4的爆炸性爆发的复制。这种起源具有特定的影响，在线虫的功能和进化的补充核受体的配体结合的作用。此外，补充的核受体包括一组非常迅速发展的基因，主要发现在染色体V上，我们提出了一个模型的谱系特异性复制从染色体上的重复和替换率大大增加。我们的研究结果提供了一个框架，研究线虫的核受体，以及考虑谱系特异性复制的功能和进化后果。
The nuclear receptor superfamily expanded in at least two episodes: one early in metazoan evolution, the second within the vertebrate lineage. An exception to this pattern is the genome of the nematode Caenorhabditis elegans, which encodes more than 270 nuclear receptors, most of them highly divergent. We generated 128 cDNA sequences for 76 C. elegans nuclear receptors, confirming that these are active genes. Among these numerous receptors are 13 orthologues of nuclear receptors found in arthropods and/or vertebrates. We show that the supplementary nuclear receptors (supnrs) originated from an explosive burst of duplications of a unique orphan receptor, HNF4. This origin has specific implications for the role of ligand binding in the function and evolution of the nematode supplementary nuclear receptors. Moreover, the supplementary nuclear receptors include a group of very rapidly evolving genes found primarily on chromosome V. We propose a model of lineage-specific duplications from a chromosome on which duplication and substitution rates are highly increased. Our results provide a framework to study nuclear receptors in nematodes, as well as to consider the functional and evolutionary consequences of lineage-specific duplications.