Ciona intestinalis Hox gene cluster:: Its dispersed structure and residual colinear expression in development
Ciona intestinalis Hox gene cluster:: Its dispersed structure and residual colinear expression in development
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DOI：
10.1073/pnas.0401389101
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发表时间：
2004-10-19
影响因子：
11.1
通讯作者：
Saiga, H
中科院分区：
文献类型：
--
作者：
Ikuta, T;Yoshida, N;Saiga, H
海鞘属于尾脊索亚门，是脊椎动物谱系中最早的分支，在幼虫发育过程中表现出典型的脊索动物形态，尽管它们随后蜕变成具有独特身体结构的成虫。最近对海鞘（Ciona intestalis）基因组的初步分析已经鉴定出9个Hox基因，然而，这些基因已经定位在5个支架上。同样，尽管有一些关于Hox成员基因的数据，但Ciona Hox基因的表达模式在很大程度上是未知的。因此，Hox基因的簇状结构和共线性仍然是一个谜。为了解决这些问题，我们使用了荧光原位杂交和全安装原位杂交技术，并检测了所有Hox以及扩展Hox成员基因（Evx和Mox）的基因组组织和时空表达。我们发现，Ciona Hox的9个基因中有7个位于一条染色体上，有一些顺序例外，其他基因，包括Evx和Mox，位于其他三条染色体上。部分Ciona Hox基因（如果不是全部的话）在幼虫中枢神经系统和幼鱼肠道中表现出空间协调表达。根据这些观察结果，我们认为Hox基因的簇组织和共线性在C肠子中处于分散和分解状态。
Ascidians, belonging to the subphylum Urochordata, the earliest branch from the lineage to the vertebrates, exhibit a prototypical morphogenesis of chordates in the larval development, although they subsequently metamorphose into adults with a unique body structure. Recent draft genome analysis of the ascidian Ciona intestinalis has identified 9 Hox genes, which, however, have been located on five scaffolds. Similarly, expression patterns of Ciona Hox genes are largely unknown, although some data have been available for a few Hox member genes. Thus, the cluster structure and colinearity of Hox genes are still an enigma in C intestinalis. To address these issues, we used fluorescence insitu hybridization and whole-mount in situ hybridization techniques and examined the genomic organization and spatiotemporal expression of all Hox as well as extended Hox member genes (Evx and Mox) of C intestinalis. We found that seven of nine Ciona Hox genes are located on a single chromosome with some ordering exceptions, and the other genes, including Evx and Mox, are located on three other chromosomes. Some Ciona Hox genes, if not all, exhibited spatially coordinated expression within the larval central nervous system and the gut of the juvenile. In light of these observations, we suggest that the cluster organization and colinearity of the Hox genes are under dispersing and disintegrating conditions in C intestinalis.