Department of Biology and VCU Life Sciences, Virginia Commonwealth University, Richmond, Virginia, USA.
Department of Pathology, Duke University, Durham, North Carolina, USA.
Dev Dyn. 2024 Apr;253(4):390-403. doi: 10.1002/dvdy.665. Epub 2023 Oct 20.
Noncanonical Wnts are morphogens that can elevate intracellular Ca, activate the Ca/calmodulin-dependent protein kinase, CaMKII, and promote cell movements during vertebrate gastrulation.
Zebrafish express seven CaMKII genes during embryogenesis; two of these, camk2b1 and camk2g1, are necessary for convergent extension (CE) cell movements. CaMKII morphant phenotypes were observed as early as epiboly. At the 1-3 somite stage, neuroectoderm and paraxial cells remained unconverged in both morphants. Later, somites lacked their stereotypical shape and were wider, more closely spaced, and body gap angles increased. At 24hpf, somite compression and notochord undulation coincided with a shorter and broader body axis. A camk2b1 crispant was generated which phenocopied the camk2b1 morphant. The levels of cell proliferation, apoptosis and paraxial and neuroectodermal markers were unchanged in morphants. Hyperactivation of CaMKII during gastrulation by transient pharmacological intervention (thapsigargin) also caused CE defects. Mosaically expressed dominant-negative CaMKII recapitulated these phenotypes and showed significant midline bifurcation. Finally, the introduction of CaMKII partially rescued Wnt11 morphant phenotypes.
Overall, these data support a model whereby cyclically activated CaMKII encoded from two genes enables cell migration during the process of CE.
非经典 Wnt 是形态发生素，可升高细胞内 Ca，激活 Ca/钙调蛋白依赖性蛋白激酶 CaMKII，并在脊椎动物原肠胚形成过程中促进细胞运动。
斑马鱼在胚胎发生过程中表达七种 CaMKII 基因；其中两种，camk2b1 和 camk2g1，对于会聚延伸（CE）细胞运动是必需的。CaMKII 形态发生缺陷表型早在胚环形成时就观察到。在 1-3 体节阶段，神经外胚层和轴旁细胞在两种形态发生缺陷中均未发生会聚。后来，体节缺乏其典型形状，并且更宽，更紧密地间隔，并且体间隙角度增加。在 24hpf 时，体节压缩和脊索波动与更短和更宽的身体轴同时发生。生成了 camk2b1 crispant，其表型与 camk2b1 形态发生缺陷相似。形态发生缺陷中细胞增殖、凋亡以及轴旁和神经外胚层标志物的水平没有变化。通过短暂的药理学干预（毒胡萝卜素）在原肠胚形成过程中过度激活 CaMKII 也会导致 CE 缺陷。异位表达显性失活 CaMKII 重现了这些表型，并显示出明显的中线分叉。最后，CaMKII 的引入部分挽救了 Wnt11 形态发生缺陷表型。
总体而言，这些数据支持这样一种模型，即两个基因编码的周期性激活的 CaMKII 使细胞在 CE 过程中迁移。
