A degenerate ParaHox gene cluster in a degenerate vertebrate
A degenerate ParaHox gene cluster in a degenerate vertebrate
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DOI：
10.1093/molbev/msm194
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发表时间：
2007-12-01
影响因子：
10.7
通讯作者：
Holland, Peter W. H.
中科院分区：
文献类型：
--
作者：
Furlong, Rebecca F.;Younger, Ruth;Holland, Peter W. H.
ParaHox基因由Gsx、Xlox和Cdx 3个同源盒基因家族组成，它们都在发育过程中起着重要作用。例如，Xlox（在脊椎动物中称为IPF1或PDX1）对脊椎动物胰腺的发育至关重要，也参与胰岛素表达的调节。无脊椎动物文文鱼有一个基因簇，其中包含来自每个基因家族的一个基因，而在迄今为止检查的所有脊椎动物中，在脊椎动物谱系的基础上都有由副hox基因簇复制产生的额外拷贝。现存的脊椎动物，从基底到硬骨和软骨鱼类，是这些多重基因何时以及如何在脊椎动物基因组中出现的问题的核心。在这里，我们报告了在2种盲鳗中定位一个ParaHox基因簇。出乎意料的是，这些基底脊椎动物已经从这个群中失去了一个功能性的Xlox基因，这与迄今为止研究的所有其他脊椎动物不同。此外，我们的系统发育分析表明，盲鳗可能在复制之前就已经从脊椎动物谱系中分化出来了，而复制在颚脊椎动物中产生了多个ParaHox集群。
The ParaHox genes consist of 3 homeobox gene families, Gsx, Xlox, and Cdx, all of which have fundamental roles in development. Xlox (known as IPF1 or PDX1 in vertebrates), for example, is crucial for development of the vertebrate pancreas and is also involved in regulation of insulin expression. The invertebrate amphioxus has a gene cluster containing one gene from each of the gene families, whereas in all vertebrates examined to date there are additional copies resultant from ParaHox gene cluster duplications at the base of the vertebrate lineage. Extant vertebrates basal to bony and cartilaginous fish are central to the question of when and how these multiple genes arose in the vertebrate genome. Here, we report the mapping of a ParaHox gene cluster in 2 species of hagfishes. Unexpectedly, these basal vertebrates have lost a functional Xlox gene from this cluster, unlike every other vertebrate examined to date. Furthermore, our phylogenetic analyses suggest that hagfishes may have diverged from the vertebrate lineage before the duplications, which created the multiple ParaHox clusters in jawed vertebrates.