Lemos C L, Sampaio P, Maiato H, Costa M, Omel'yanchuk L V, Liberal V, Sunkel C E
Laboratório de Genética Molecular da Mitose, Instituto de Biologia Molecular e Celular, Universidade do Porto, R.Campo Alegre, 823, 4150-180 Porto, Portugal.
EMBO J. 2000 Jul 17;19(14):3668-82. doi: 10.1093/emboj/19.14.3668.
Through mutational analysis in Drosopjila we have identified the gene multiple asters (mast), which encodes a new 165 kDa protein. mast mutant neuroblasts are highly polyploid and show severe mitotic abnormalities including the formation of mono- and multi-polar spindles organized by an irregular number of microtubule-organizing centres of abnormal size and shape. The mast gene product is evolutionarily conserved since homologues were identified from yeast to man, revealing a novel protein family. Antibodies against Mast and analysis of tissue culture cells expressing an enhanced green fluorescent protein-Mast fusion protein show that during mitosis, this protein localizes to centrosomes, the mitotic spindle, centromeres and spindle midzone. Microtubule-binding assays indicate that Mast is a microtubule-associated protein displaying strong affinity for polymerized microtubules. The defects observed in the mutant alleles and the intracellular localization of the protein suggest that Mast plays an essential role in centrosome separation and organization of the bipolar mitotic spindle.
通过对果蝇的突变分析，我们鉴定出了多星基因（mast），该基因编码一种新的165 kDa蛋白质。mast突变的神经母细胞高度多倍体化，并表现出严重的有丝分裂异常，包括由数量不规则、大小和形状异常的微管组织中心组织形成单极和多极纺锤体。由于从酵母到人都鉴定出了同源物，mast基因产物在进化上是保守的，揭示了一个新的蛋白质家族。针对Mast的抗体以及对表达增强型绿色荧光蛋白-Mast融合蛋白的组织培养细胞的分析表明，在有丝分裂期间，该蛋白定位于中心体、有丝分裂纺锤体、着丝粒和纺锤体中间区。微管结合试验表明，Mast是一种微管相关蛋白，对聚合微管具有很强的亲和力。在突变等位基因中观察到的缺陷以及该蛋白在细胞内的定位表明，Mast在中心体分离和双极有丝分裂纺锤体的组织中起着至关重要的作用。
