A Hox class 3 orthologue from the spider Cupiennius salei is expressed in a Hox-gene like fashion
A Hox class 3 orthologue from the spider Cupiennius salei is expressed in a Hox-gene like fashion
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DOI：
10.1007/s004270050218
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发表时间：
1998-12-01
影响因子：
2.4
通讯作者：
Tautz, D
中科院分区：
文献类型：
--
作者：
Damen, WGM;Tautz, D
昆虫中的3类Hox基因直向同源物zerknullt（zen）不沿着前后轴表达，而仅在胚外组织中表达，这表明它已经失去了作为正常Hox基因的功能。为了分析这种Hox基因功能的丧失是否已经发生在基础节肢动物谱系中，我们从蜘蛛Cupiennius salei中分离出了Hox 3直系同源物。与昆虫的10个序列相比，蜘蛛Hox 3基因的直向同源物Cs-Hox 3与其他门（包括脊索动物）的3类Hox基因具有很高的序列相似性。在早期胚胎中的原位杂交表明，它是在一个连续的区域覆盖pedipalp节和四个腿轴承节。这种表达模式表明Cs-Hox 3具有Hox基因样功能。另一方面，表达模式并不严格遵循共线性规则，因为它与蜘蛛的1类直向同源物Cs-lab的表达域完全重叠。尽管如此，我们的数据表明，节肢动物的祖先必须有一个3类Hox基因的功能，在前后轴规范，这种功能已经失去了导致昆虫的谱系。
The class 3 Hox gene orthologue in insects, zerknullt (zen), is not expressed along the anterior-posterior axis, but only in extra-embryonic tissues, suggesting that it has lost its function as a normal Hox gene. To analyse whether this loss of Hox gene function has already occurred in a basal arthropod lineage, we have isolated a Hox3 orthologue from the spider Cupiennius salei. In contrast to the insect ten sequences, which have a highly diverged homeobox, the spider Hox3 gene orthologue, Cs-Hox3, shows a high sequence similarity to the class 3 Hox genes of other phyla, including chordates. In situ hybridization in early embryos shows that it is expressed in a continuous region covering the pedipalp segment and the four leg-bearing segments. This expression pattern suggests a Hox-gene-like function for Cs-Hox3. On the other hand, the expression pattern does not strictly follow the colinearity rule, as it overlaps fully with the expression domain of the class 1 orthologue of the spider, Cs-lab. Still, our data suggest that the ancestor of the arthropods must have had a class 3 Hox gene with a function in anterior-posterior axis specification and that this function has been lost in the lineage leading to the insects.