Desmin is a muscle-specific intermediate filament protein that has fundamental role in muscle structure and force transmission. Whereas human desmin protein is encoded by a single gene, two desmin paralogs (desma and desmb) exist in zebrafish. Desma and desmb show differential spatiotemporal expression during zebrafish embryonic and larval development, being similarly expressed in skeletal muscle until hatching, after which expression of desmb shifts to gut smooth muscle. We generated knockout (KO) mutant lines carrying loss-of-function mutations for each gene by using CRISPR/Cas9. Mutants are viable and fertile, and lack obvious skeletal muscle, heart or intestinal defects. In contrast to morphants, knockout of each gene did not cause any overt muscular phenotype, but did alter calcium flux in myofibres. These results point to a possible compensation mechanism in these mutant lines generated by targeting nonsense mutations to the first coding exon.

中文翻译：

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斑马鱼desmin基因的敲除不会引起骨骼肌变性，但会改变钙通量

结蛋白是一种肌肉特异性中间丝蛋白，在肌肉结构和力传递中具有基本作用。人desmin蛋白由单个基因编码，而斑马鱼中存在两个desmin旁系同源物（desma和desmb）。Desma和desmb在斑马鱼的胚胎和幼虫发育过程中表现出不同的时空表达，在骨骼肌中直到孵化时都类似地表达，之后desmb的表达转移到肠道平滑肌。我们通过使用CRISPR / Cas9生成了每个基因带有功能丧失突变的敲除（KO）突变株。突变体是可行的和可育的，并且缺乏明显的骨骼肌，心脏或肠道缺陷。与吗啡不同，每个基因的敲除不会引起任何明显的肌肉表型，但会改变肌纤维中的钙通量。这些结果表明在通过将无义突变靶向第一个编码外显子而产生的这些突变株中的可能的补偿机制。