Drosophila singed, a fascin homolog, is required for actin bundle formation during oogenesis and bristle extension.
Drosophila singed, a fascin homolog, is required for actin bundle formation during oogenesis and bristle extension.
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DOI：
10.1083/jcb.125.2.369
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发表时间：
1994-04
影响因子：
7.8
通讯作者：
Cooley, L
中科院分区：
文献类型：
--
作者：
Cant, K;Knowles, B A;Mooseker, M S;Cooley, L
果蝇烧焦突变体因其多节刚毛表型而命名，但严重的等位基因也是雌性不育的。最近，烧焦的蛋白质被证明与棘皮动物fascin具有35%的肽同一性。成束蛋白存在于海胆卵微绒毛的肌动蛋白丝束和体腔细胞的丝状伪足延伸中。我们发现，果蝇烧焦的是所需的肌动蛋白丝束形成在卵子发生过程中的细胞质中的护士细胞;在严重的突变体，细胞质肌动蛋白丝束的情况下，护士细胞核入住环管和阻断护士细胞的细胞质运输。在细胞伸展过程中，有组织的肌动蛋白丝束形成刚毛也需要烧焦;在严重的突变体中，小的无组织肌动蛋白丝束缺乏结构完整性，并允许刚毛在伸展过程中弯曲和分支。烧焦的蛋白质也表达在发展中的卵室和发展中的刚毛的插座细胞的迁移细胞，但没有缺陷，在这些细胞中观察到烧焦的突变体。纯化，细菌表达烧焦的蛋白束肌动蛋白纤维在体外与纯化的海胆肌成束蛋白相同的化学计量报告。染色饱和的肌动蛋白束具有约1：4.3的染色/肌动蛋白的摩尔比，并且使用电子显微镜观察到12 nm的横向交叉带图案。我们的研究结果表明，烧焦的蛋白质所需的肌动蛋白丝束的形成，是果蝇同源的棘皮动物fascin。
Drosophila singed mutants were named for their gnarled bristle phenotype but severe alleles are also female sterile. Recently, singed protein was shown to have 35% peptide identity with echinoderm fascin. Fascin is found in actin filament bundles in microvilli of sea urchin eggs and in filopodial extensions in coelomocytes. We show that Drosophila singed is required for actin filament bundle formation in the cytoplasm of nurse cells during oogenesis; in severe mutants, the absence of cytoplasmic actin filament bundles allows nurse cell nuclei to lodge in ring canals and block nurse cell cytoplasm transport. Singed is also required for organized actin filament bundle formation in the cellular extension that forms a bristle; in severe mutants, the small disorganized actin filament bundles lack structural integrity and allow bristles to bend and branch during extension. Singed protein is also expressed in migratory cells of the developing egg chamber and in the socket cell of the developing bristle, but no defect is observed in these cells in singed mutants. Purified, bacterially expressed singed protein bundles actin filaments in vitro with the same stoichiometry reported for purified sea urchin fascin. Singed-saturated actin bundles have a molar ratio of singed/actin of approximately 1:4.3 and a transverse cross-banding pattern of 12 nm seen using electron microscopy. Our results suggest that singed protein is required for actin filament bundle formation and is a Drosophila homolog of echinoderm fascin.