Department of Developmental Genetics, National Institute of Genetics, 1111 Yata, Mishima 411-8540, Japan.
Mech Dev. 2013 Feb;130(2-3):132-42. doi: 10.1016/j.mod.2012.10.001. Epub 2012 Oct 17.
During gastrulation in Drosophila melanogaster, coordinated apical constriction of the cellular surface drives invagination of the mesoderm anlage. Forces generated by the cortical cytoskeletal network have a pivotal role in this cellular shape change. Here, we show that the organisation of cortical actin is essential for stabilisation of the cellular surface against contraction. We found that mutation of genes related to heterotrimeric G protein (HGP) signaling, such as Gβ13F, Gγ1, and ric-8, results in formation of blebs on the ventral cellular surface. The formation of blebs is caused by perturbation of cortical actin and induced by local surface contraction. HGP signaling mediated by two Gα subunits, Concertina and G-iα65A, constitutively regulates actin organisation. We propose that the organisation of cortical actin by HGP is required to reinforce the cortex so that the cells can endure hydrostatic stress during tissue folding.
在果蝇的原肠胚形成过程中，细胞表面的协调顶端收缩驱动中胚层原基的内陷。皮质细胞骨架网络产生的力在这种细胞形状变化中起着关键作用。在这里，我们表明皮质肌动蛋白的组织对于稳定细胞表面抵抗收缩是必不可少的。我们发现，与异三聚体 G 蛋白 (HGP) 信号相关的基因（如 Gβ13F、Gγ1 和 ric-8）的突变会导致腹侧细胞表面出现泡状结构。泡状结构的形成是由皮质肌动蛋白的扰动引起的，并由局部表面收缩诱导。由两个 Gα 亚基 Concertina 和 G-iα65A 介导的 HGP 信号转导持续调节肌动蛋白的组织。我们提出，HGP 介导的皮质肌动蛋白的组织对于增强皮质是必需的，以便细胞能够在组织折叠过程中承受流体静压力。
