Karlsruhe Institute of Technology (KIT), Institute of Toxicology and Genetics (ITG), Eggenstein-Leopoldshafen, Germany.
PLoS One. 2018 Nov 20;13(11):e0207747. doi: 10.1371/journal.pone.0207747. eCollection 2018.
In zebrafish, the gene choline acetyltransferase a (chata) encodes one of the two ChAT orthologs responsible for the synthesis of acetylcholine. Acetylcholine (ACh) is essential for neuromuscular transmission and its impaired synthesis by ChAT can lead to neuromuscular junction disorders such as congenital myasthenic syndromes in humans. We have identified a novel mutation in the chata gene of zebrafish, chatatk64, in a collection of uncharacterised ENU-induced mutants. This mutant carries a missense mutation in the codon of a highly conserved serine changing it to an arginine (S102R). This serine is conserved among ChATs from zebrafish, rat, mice and chicken to humans. It resides within the catalytic domain and in the vicinity of the active site of the enzyme. However, it has not been reported so far to be required for enzymatic activity. Modelling of the S102R variant change in the ChAT protein crystal structure suggests that the change affects protein structure and has a direct impact on the catalytic domain of the protein which abolishes embryo motility almost completely.
在斑马鱼中，胆碱乙酰转移酶 a（chata）基因编码负责合成乙酰胆碱的两个 ChAT 同源物之一。乙酰胆碱（ACh）对于神经肌肉传递至关重要，ChAT 合成受损可导致神经肌肉接头疾病，如人类先天性肌无力综合征。我们在一组未表征的ENU 诱导突变体中鉴定出斑马鱼 chata 基因中的一种新突变 chatatk64。该突变携带一个错义突变，即在高度保守的丝氨酸密码子处变为精氨酸（S102R）。该丝氨酸在来自斑马鱼、大鼠、小鼠和鸡到人类的 ChAT 中保守。它位于酶的催化结构域和活性位点附近。然而，迄今为止，尚未报道该丝氨酸对于酶活性是必需的。ChAT 蛋白晶体结构中 S102R 变体变化的建模表明，该变化影响蛋白结构，并直接影响蛋白的催化结构域，几乎完全使胚胎运动能力丧失。
