Isolation of Dlx and Emx gene cognates in an agnathan species, Lampetra japonica, and their expression patterns during embryonic and larval development:: Conserved and diversified regulatory patterns of homeobox genes in vertebrate head evolution
Isolation of Dlx and Emx gene cognates in an agnathan species, Lampetra japonica, and their expression patterns during embryonic and larval development:: Conserved and diversified regulatory patterns of homeobox genes in vertebrate head evolution
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DOI：
10.1002/jez.6
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发表时间：
2001-04-15
影响因子：
--
通讯作者：
Kuratani, S
中科院分区：
文献类型：
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作者：
Myojin, M;Ueki, T;Kuratani, S
从日本七鳃鳗（Lampetra japonica）的胚胎cDNA中分离出脊椎动物同源异型盒基因Emx和Dir的同源同源基因。氨基酸序列分析表明，DL同源物与颚口类Dlx 1和Dlx 6类群的共同祖先关系密切，命名为LjDlx 1/6。Southern杂交分析不能排除L. japonica对LjDlx 1/6和LjEmx都有一个以上的paramorphic，LjEmx是Emx的同源七鳃鳗。LjDlx 1/6的表达在空间上和发育上都受到调节，其转录本主要存在于颅面和咽间充质以及前脑中。LjEmx的表达模式在胚胎发生过程中发生了显着变化;表达最初出现在整个神经管和中胚层，其次下调，其次在颅神经节和颅面间充质。端脑未见LjEmx特异性表达。Dlx和Otx基因表达模式的比较表明，脊椎动物大脑的神经元模式共享。缺乏EMX表达意味着七鳃鳗端脑的图案是不是基于三方计划，已假定在gnathostomes。LjDlx 1/6在上唇和LjEmx在颅面间充质中的表达域是在有颌动物中尚未发现的特有特征。这种表达模式的差异可能是无颌类和有颌类下颌弓不同形态发生途径的基础。(C)2001 Wiley-Liss，Inc.
Agnathan cognates of vertebrate homeobox genes, Emx and Dir, were isolated from embryonic cDNA of a Japanese marine lamprey, Lampetra japonica. Analyses of amino acid sequences indicated that the DL cognate was closely related to the common ancestor of gnathostome Dlx1 and Dlx6 groups and termed LjDlx1/6. Southern blot analyses could not rule out the possibility that L. japonica possesses more than one paralog for both LjDlx1/6 and LjEmx, the lamprey cognate of Emx. Expression of LjDlx1/6 was regulated spatially as well as developmentally, and its transcripts were mainly found in the craniofacial and pharyngeal mesenchyme and in the forebrain. The expression pattern of LjEmx changed dramatically during embryogenesis; expression was seen initially in the entire neural tube and mesoderm, which were secondarily downregulated, and secondarily in cranial nerve ganglia and in the craniofacial mesenchyme. No Specific expression of LjEmx was seen in the telencephalon. Comparisons of Dlx and Otx gene expression patterns suggested a shared neuromeric pattern of the vertebrate brain. Absence of Emx expression implied that the patterning of the lamprey telencephalon is not based on the tripartite plan that has been presumed in gnathostomes. Expression domains of LjDlx1/6 in the upper lip and of LjEmx in the craniofacial mesenchyme were peculiar features that have not been known in gnathostomes. Such differences in expression pattern may underlie distinct morphogenetic pathway of the mandibular arch between the agnathans and gnathostomes. (C) 2001 Wiley-Liss, Inc.