EXPRESSION PATTERNS OF MESSENGER-RNAS FOR THE GAP JUNCTION PROTEINS CONNEXIN43 AND CONNEXIN42 SUGGEST THEIR INVOLVEMENT IN CHICK LIMB MORPHOGENESIS AND SPECIFICATION OF THE ARTERIAL VASCULATURE
EXPRESSION PATTERNS OF MESSENGER-RNAS FOR THE GAP JUNCTION PROTEINS CONNEXIN43 AND CONNEXIN42 SUGGEST THEIR INVOLVEMENT IN CHICK LIMB MORPHOGENESIS AND SPECIFICATION OF THE ARTERIAL VASCULATURE
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DOI：
10.1002/aja.1001990208
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发表时间：
1994-02-01
影响因子：
2.5
通讯作者：
KOSHER, RA
中科院分区：
文献类型：
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作者：
DEALY, CN;BEYER, EC;KOSHER, RA
缝隙连接是鸡肢芽发育过程中的一个重要组成部分，它与鸡肢芽的形态发生密切相关。我们已经研究了连接蛋白家族的两个成员，连接蛋白43（Cx43）和连接蛋白42（Cx42），在鸡肢芽和胚胎的早期发育过程中的原位杂交的表达模式。Cx43 mRNA在顶端外胚层嵴（AER）中表达量很高，这促进了肢芽中胚层细胞的生长，并在多指双足畸形-5突变胚胎肢芽的异位AER中表达。相反，在肢体发育的早期阶段，在nonridge Limb外胚层中几乎没有Cx43的表达。这些结果表明，Cx43缝隙连接可能整合的活性的细胞组成的AER和区室化成一个功能不同的实体能够指导肢体生长。此外，Cx43在早期肢芽的后亚嵴中胚层中表现出高表达，该中胚层响应于AER而生长，但在前中胚层中几乎没有表达。Cx43转录本的这种分级分布与沿着前后（AP）轴的间隙连接通讯的功能梯度相关，并表明Cx43间隙连接可能参与AP轴上的模式形成。在发育的后期阶段，Cx43在腕骨和掌骨的前软骨浓缩中瞬时表达，此时发生触发软骨分化的关键细胞-细胞相互作用。相反，在发育中的肢体中，Cx42仅由中央动脉表达。在鸡胚的其余部分中，Cx42由包含动脉脉管系统的血管以高量表达，但不由静脉脉管系统表达。因此，Cx42缝隙连接可能参与肢体和胚胎动脉血管系统的规范。Cx42而非Cx43在心室中表达，并且通过沿着将体节的硬节的头侧和尾侧半部分隔成不同的通信隔室的硬节内裂的细胞表达。(C)1994 Wiley-Liss，Inc.
Gap junctions which comprise a family of proteins called connexins have been implicated in the morphogenesis of the chick limb bud. We have examined the expression patterns of two members of the connexin family, connexin43 (Cx43) and connexin42 (Cx42), during the early development of the chick limb bud and embryo by in situ hybridization. Cx43 mRNA is expressed in high amounts in the apical ectodermal ridge (AER), which promotes the outgrowth of the mesodermal cells of the limb bud, and in the ectopic AER of the limb buds of polydactylous diplopodia-5 mutant embryos. In contrast, little Cx43 expression is detectable in nonridge Limb ectoderm at early stages of limb development. These results suggest that Cx43 gap junctions may integrate the activity of the cells comprising the AER and compartmentalize them into a functionally distinct entity capable of directing limb outgrowth. In addition, Cx43 exhibits high expression in the posterior subridge mesoderm of the early limb bud that is growing out in response to the AER, but little expression in the anterior mesoderm. This graded distribution of Cx43 transcripts correlates with a functional gradient of gap junctional communication along the anteroposterior (AP) axis, and suggests that Cx43 gap junctions may be involved in pattern formation across the AP axis. At later stages of development, Cx43 is transiently expressed in high amounts in the precartilage condensations of the carpals and metacarpals, at a time when critical cell-cell interactions are occurring that trigger cartilage differentiation. In contrast, in the developing Limb, Cx42 is expressed exclusively by the central artery. In the remainder of the chick embryo, Cx42 is expressed in high amounts by the vessels comprising the arterial vasculature, but is not expressed by the venous vasculature. Thus, Cx42 gap junctions may be involved in specification of the arterial vasculature of the limb and embryo. Cx42, but not Cx43, is expressed in the ventricle of the heart, and by cells along the intrasclerotomal fissure that separates the rostral and caudal halves of the sclerotome of somites into distinct communication compartments. (C) 1994 Wiley-Liss, Inc.