Overexpression of the tinman-related genes XNkx-2.5 and XNkx-2.3 in Xenopus embryos results in myocardial hyperplasia.
Overexpression of the tinman-related genes XNkx-2.5 and XNkx-2.3 in Xenopus embryos results in myocardial hyperplasia.
复制标题
DOI：
--
复制
发表时间：
1996-11
期刊：
影响因子：
4.6
通讯作者：
O. Cleaver;K. Patterson;P. Krieg
中科院分区：
文献类型：
--
作者：
O. Cleaver;K. Patterson;P. Krieg
果蝇tinman是一种NK类同源盒基因，是形成背血管（相当于昆虫的脊椎动物心脏）所必需的。与tinman相关的脊椎动物序列，例如小鼠Nkx-2.5、鸡cNkx-2.5、爪蟾XNkx-2.5和XNkx-2.3在心脏前体细胞和参与心脏中胚层诱导的组织中表达。缺乏功能性 Nkx-2.5 基因的小鼠会因心脏缺陷而死亡。为了确定tinman相关序列在心脏发育中的作用，我们在非洲爪蟾胚胎中过表达XNkx-2.3和XNkx-2.5。由此产生的胚胎形态正常，只是心脏增大。扩大的心脏表型是由于心肌细胞总数增加（增生）引起的心肌增厚。在过度表达的胚胎中，未检测到心脏分化标记物的异位表达或早熟表达。这些结果表明 XNkx-2.3 和 XNkx-2.5 都是 Tinman 的功能同源物，负责维持心脏区域。
Drosophila tinman is an NK-class homeobox gene required for formation of the dorsal vessel, the insect equivalent of the vertebrate heart. Vertebrate sequences related to tinman, such as mouse Nkx-2.5, chicken cNkx-2.5, Xenopus XNkx-2.5 and XNkx-2.3 are expressed in cardiac precursors and in tissues involved in induction of cardiac mesoderm. Mice which lack a functional Nkx-2.5 gene die due to cardiac defects. To determine the role of tinman-related sequences in heart development, we have overexpressed both XNkx-2.3 and XNkx-2.5 in Xenopus laevis embryos. The resulting embryos are morphologically normal except that they have enlarged hearts. The enlarged heart phenotype is due to a thickening of the myocardium caused by an increase in the overall number of myocardial cells (hyperplasia). Neither ectopic nor precocious expression of cardiac differentiation markers is detectable in overexpressing embryos. These results suggest that both XNkx-2.3 and XNkx-2.5 are functional homologues of tinman, responsible for maintenance of the heart field.