Drosophila paramyosin is important for myoblast fusion and essential for myofibril formation.
Drosophila paramyosin is important for myoblast fusion and essential for myofibril formation.
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果蝇帕莫辛对于肌细胞融合很重要，对于肌膜纤维的形成至关重要。
DOI：
10.1083/jcb.200208180
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发表时间：
2003-03-17
影响因子：
7.8
通讯作者：
Bernstein, Sanford I
中科院分区：
文献类型：
--
作者：
Liu, Hongjun;Mardahl-Dumesnil, Michelle;Sweeney, Sean T;O'Kane, Cahir J;Bernstein, Sanford I
副肌球蛋白是无脊椎动物肌肉中粗丝的主要结构蛋白。卷曲盘绕的副肌球蛋白二聚体形成了这些细丝的准晶核心，核心表面排列着马达蛋白肌球蛋白。为了研究副肌球蛋白在肌原纤维组装和肌肉收缩中的作用，我们通过动员位于其启动子区域的P元件来功能性地干扰果蝇的副肌球蛋白基因。纯合子副肌球蛋白突变体在胚胎晚期死亡。突变体在胚胎体壁肌肉中的成肌细胞融合和肌原纤维组装方面都显示出缺陷。突变胚胎具有异常的体壁肌肉纤维模式，这是由于成肌细胞融合缺陷引起的。此外，肌节单位不能正确组装，肌肉收缩能力受损。我们通过用副肌球蛋白转基因将纯合子副肌球蛋白突变体挽救到成年，证实了这些缺陷是副肌球蛋白特有的。对正常胚胎的抗体分析表明，副肌球蛋白在胚胎发育早期以细胞质蛋白的形式积累，然后组装成粗丝。我们得出结论，副肌球蛋白在成肌细胞融合中发挥了意想不到的作用，并且对肌原纤维组装和肌肉收缩非常重要。
Paramyosin is a major structural protein of thick filaments in invertebrate muscles. Coiled-coil dimers of paramyosin form a paracrystalline core of these filaments, and the motor protein myosin is arranged on the core surface. To investigate the function of paramyosin in myofibril assembly and muscle contraction, we functionally disrupted the Drosophila melanogaster paramyosin gene by mobilizing a P element located in its promoter region. Homozygous paramyosin mutants die at the late embryo stage. Mutants display defects in both myoblast fusion and in myofibril assembly in embryonic body wall muscles. Mutant embryos have an abnormal body wall muscle fiber pattern arising from defects in myoblast fusion. In addition, sarcomeric units do not assemble properly and muscle contractility is impaired. We confirmed that these defects are paramyosin-specific by rescuing the homozygous paramyosin mutant to adulthood with a paramyosin transgene. Antibody analysis of normal embryos demonstrated that paramyosin accumulates as a cytoplasmic protein in early embryo development before assembling into thick filaments. We conclude that paramyosin plays an unexpected role in myoblast fusion and is important for myofibril assembly and muscle contraction.