Abstract：
BACKGROUND: Noncanonical Wnts are morphogens that can elevate intracellular Ca2+, activate the Ca2+/calmodulin-dependent protein kinase, CaMKII, and promote cell movements during vertebrate gastrulation.
RESULTS: 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.
CONCLUSIONS: Overall, these data support a model whereby cyclically activated CaMKII encoded from two genes enables cell migration during the process of CE.
RESULTS: 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.
CONCLUSIONS: Overall, these data support a model whereby cyclically activated CaMKII encoded from two genes enables cell migration during the process of CE.
摘要：
背景：非规范Wnts是可以升高细胞内Ca2+的形态发生原，激活Ca2+/钙调蛋白依赖性蛋白激酶，CaMKII,并促进脊椎动物原肠胚形成过程中的细胞运动。
结果：斑马鱼在胚胎发生过程中表达七个CaMKII基因；其中两个，camk2b1和camk2g1是收敛扩展(CE)细胞运动所必需的。早在外突时就观察到了CaMKII形态表型。在1-3阶段，神经外胚层和旁轴细胞在两个形态中均未融合。稍后，体节缺乏刻板的形状，而且更宽，间隔更近，和身体间隙角度增加。在24hpf，体节压缩和脊索起伏与较短和较宽的身体轴重合。生成了camk2b1保鲜剂，该保鲜剂显色了camk2b1形态。细胞增殖的水平，细胞凋亡和旁轴和神经外胚层标记在形态中没有变化。通过瞬时药物干预（thapsigargin）在原肠胚形成过程中CaMKII的过度活化也导致CE缺陷。马赛克表达的显性负CaMKII概括了这些表型，并显示出明显的中线分叉。最后,CaMKII的引入部分挽救了Wnt11形态表型。
结论：总体而言，这些数据支持一个模型，其中由两个基因编码的周期性激活的CaMKII使细胞在CE过程中迁移。
结果：斑马鱼在胚胎发生过程中表达七个CaMKII基因；其中两个，camk2b1和camk2g1是收敛扩展(CE)细胞运动所必需的。早在外突时就观察到了CaMKII形态表型。在1-3阶段，神经外胚层和旁轴细胞在两个形态中均未融合。稍后，体节缺乏刻板的形状，而且更宽，间隔更近，和身体间隙角度增加。在24hpf，体节压缩和脊索起伏与较短和较宽的身体轴重合。生成了camk2b1保鲜剂，该保鲜剂显色了camk2b1形态。细胞增殖的水平，细胞凋亡和旁轴和神经外胚层标记在形态中没有变化。通过瞬时药物干预（thapsigargin）在原肠胚形成过程中CaMKII的过度活化也导致CE缺陷。马赛克表达的显性负CaMKII概括了这些表型，并显示出明显的中线分叉。最后,CaMKII的引入部分挽救了Wnt11形态表型。
结论：总体而言，这些数据支持一个模型，其中由两个基因编码的周期性激活的CaMKII使细胞在CE过程中迁移。
