Expression of a novel receptor tyrosine kinase gene and a paired-like homeobox gene provides evidence of differences in patterning at the oral and aboral ends of hydra
Expression of a novel receptor tyrosine kinase gene and a paired-like homeobox gene provides evidence of differences in patterning at the oral and aboral ends of hydra
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DOI：
10.1006/dbio.2000.9653
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发表时间：
2000-04-15
影响因子：
2.7
通讯作者：
Steele, RE
中科院分区：
文献类型：
--
作者：
Bridge, DM;Stover, NA;Steele, RE
使用来自两个基因的表达数据检查水螅体柱的背口端的轴向图案。一个是护胫，是一种新的受体蛋白酪氨酸激酶基因，表达于花梗的外胚层，即靠近基盘的体柱末端。另一个基因是manacle，是一个在分化中的基盘外胚层中表达的配对同源盒基因。在背口端再生过程中，束缚的表达先于护胫的表达。这一结果与基盘组织诱导花序梗组织的要求是一致的。我们的数据与口端再生的数据形成对比。在口端再生过程中，首先检测到位于最末端口端（下节）下方的触角组织的标记。后来，下节本身的标记出现在再生尖端，而腱标记则转移到下面的区域。其他证据表明，组织可以形成基盘，而不需要经过一个阶段，作为花梗组织来自氯化锂诱导的异位基盘组织斑块的形成。在基盘斑块形成过程中，Manacle异位表达，而Shin guard则不表达。这些基因的检测也提供了关于芽中无口端发育的新信息。虽然成年水螅是径向对称的，这两个基因在芽的aboral端的表达最初是不对称的，首先出现在最接近父母的基盘的芽的一侧。这种不对称性可以用外翻形成芽的体柱组织中位置信息的差异来解释。正如这一假说所预测的，移植逆转外翻体柱组织的方向也逆转了不对称基因表达的方向。(C)北京大学出版社.
Axial patterning of the aboral end of the hydra body column was examined using expression data from two genes. One, shin guard, is a novel receptor protein-tyrosine kinase gene expressed in the ectoderm of the peduncle, the end of the body column adjacent to the basal disk. The other gene, manacle, is a paired-like homeobox gene expressed in differentiating basal disk ectoderm. During regeneration of the aboral end, expression of manacle precedes that of shin guard. This result is consistent with a requirement for induction of peduncle tissue by basal disk tissue. Our data contrast with data on regeneration of the oral end. During oral end regeneration, markers for tissue of the tentacles, which lie below the extreme oral end (the hypostome), are detected first. Later, markers for the hypostome itself appear at the regenerating tip, with tentacle markers displaced to the region below. Additional evidence that tissue can form basal disk without passing through a stage as peduncle tissue comes from LiCl-induced formation of patches of ectopic basal disk tissue. While manacle is ectopically expressed during formation of basal disk patches, shin guard is not. The genes examined also provide new information on development of the aboral end in buds. Although adult hydra are radially symmetrical, expression of both genes in the bud's aboral end is initially asymmetrical, appearing first on the side of the bud closest to the parent's basal disk. The asymmetry can be explained by differences in positional information in the body column tissue that evaginates to form a bud. As predicted by this hypothesis, grafts reversing the orientation of evaginating body column tissue also reverse the orientation of asymmetrical gene expression. (C) 2000 Academic Press.