The molecular control of spatial patterning in amphioxus
The molecular control of spatial patterning in amphioxus
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DOI：
10.1017/s0025315400035657
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发表时间：
1994-02
影响因子：
1.2
通讯作者：
P. Holland;J. Garcia-Fernández;L. Holland;N. Williams;N. Holland
中科院分区：
文献类型：
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作者：
P. Holland;J. Garcia-Fernández;L. Holland;N. Williams;N. Holland
文昌鱼胚胎学与脊椎动物胚胎学具有共同的特征，反映了两个类群之间的密切系统发育关系。文昌鱼与脊椎动物的不同之处在于，它的器官发生和颅的形态发生并不复杂，而且沿着身体前后轴的特化程度也较低。在这里，我们说明了这一点，通过描述文昌鱼种，文昌鱼floridae的胚胎学。为了进一步了解这些类群的起源，进化分歧和比较胚胎学，我们比较了文昌鱼和脊椎动物胚胎发育的分子控制。对于这些分析，我们专注于同源异型盒基因：一个多元化的多基因家族牵连在许多后生动物的发育控制。我们报告的结果，PCR为基础的实验表明，文昌鱼基因组具有同源盒基因从几个公认的基因类。PCR实验还表明，文昌鱼的'Hox'和'Msx'类同源盒基因比脊椎动物少。因此，我们认为文昌鱼可能是同源异型盒基因家族复杂性和脊椎动物发育控制复杂性进化的中间阶段的后代。胚胎发生过程中的基因表达模式已被描述为一个文昌鱼同源盒基因的Hox类。该基因主要在文昌鱼神经胚、胚胎和幼体的神经管中表达，但表达空间有限。表达数据使我们建议，Hox基因参与文昌鱼神经管的空间模式的控制，数据也被解释为提供洞察可能的同源性之间的文昌鱼和脊椎动物的身体计划。
The embryology of amphioxus (Chordata: Cephalochordata) has features in common with vertebrate embryology, reflecting a close phylogenetic relationship between the two taxa. Amphioxus differs from vertebrates, however, in having less complex organogenesis and cranial morphogenesis, and less specialization along the anteroposterior body axis. Here we illustrate this by describing the embryology of an amphioxus species, Branchiostoma floridae. To gain further insight into the origins, evolutionary divergence and comparative embryology of these taxa, we are comparing the molecular control of embryonic development in amphioxus and vertebrates. For these analyses, we are focusing on homeobox genes: a diverse multigene family implicated in developmental control in many Metazoa. We report the results of PCR-based experiments which reveal that the amphioxus genome has homeobox genes from several recognized gene classes. The PCR experiments also suggest that amphioxus has fewer ‘Hox’ and ‘Msx’ class homeobox genes than do vertebrates. We suggest, therefore, that amphioxus may be a living descendant from an intermediate stage in the evolution of homeobox gene family complexity, and the complexity of vertebrate developmental control. The pattern of gene expression during embryogenesis has been described for one amphioxus homeobox gene of the Hox class. This gene is primarily expressed in the presumptive neural tube of amphioxus neurulae, later embryos and larvae, in a spatially-restricted manner. The expression data lead us to suggest that Hox genes are involved in the control of spatial patterning in the neural tube of amphioxus; the data are also interpreted as giving insight into possible homology between the amphioxus and vertebrate body plans.