Frémion F, Astier M, Zaffran S, Guillèn A, Homburger V, Sémériva M
Laboratoire de Génétique et Physiologie du Développement, UMR 6545 CNRS-Université, IBDM CNRS-INSERM-Université de la Méditerranée, Campus de Luminy, 13288 Marseille Cedex 09, France.
J Cell Biol. 1999 May 31;145(5):1063-76. doi: 10.1083/jcb.145.5.1063.
The gene encoding the alpha subunit of the Drosophila Go protein is expressed early in embryogenesis in the precursor cells of the heart tube, of the visceral muscles, and of the nervous system. This early expression coincides with the onset of the mesenchymal-epithelial transition to which are subjected the cardial cells and the precursor cells of the visceral musculature. This gene constitutes an appropriate marker to follow this transition. In addition, a detailed analysis of its expression suggests that the cardioblasts originate from two subpopulations of cells in each parasegment of the dorsal mesoderm that might depend on the wingless and hedgehog signaling pathways for both their determination and specification. In the nervous system, the expression of Goalpha shortly precedes the beginning of axonogenesis. Mutants produced in the Goalpha gene harbor abnormalities in the three tissues in which the gene is expressed. In particular, the heart does not form properly and interruptions in the heart epithelium are repeatedly observed, henceforth the brokenheart (bkh) name. Furthermore, in the bkh mutant embryos, the epithelial polarity of cardial cells was not acquired (or maintained) in various places of the cardiac tube. We predict that bkh might be involved in vesicular traffic of membrane proteins that is responsible for the acquisition of polarity.
果蝇Go蛋白α亚基的编码基因在胚胎发育早期，于心管、内脏肌肉和神经系统的前体细胞中表达。这种早期表达与心肌细胞和内脏肌肉组织前体细胞所经历的间充质-上皮转变的开始相吻合。该基因构成了追踪这一转变的合适标记。此外，对其表达的详细分析表明，成心肌细胞起源于背侧中胚层每个副节中的两个细胞亚群，这两个亚群的确定和特化可能依赖于无翅和刺猬信号通路。在神经系统中，Goα的表达略早于轴突发生的开始。Goα基因突变产生的突变体在该基因表达的三种组织中存在异常。特别是，心脏不能正常形成，并且在心脏上皮中反复观察到中断，因此得名心碎（bkh）。此外，在bkh突变体胚胎中，心管不同部位的心肌细胞上皮极性未获得（或维持）。我们预测bkh可能参与负责极性获得的膜蛋白的囊泡运输。
