Oakley B R, Oakley C E, Yoon Y, Jung M K
Department of Molecular Genetics, Ohio State University, Colombus 43210.
Cell. 1990 Jun 29;61(7):1289-301. doi: 10.1016/0092-8674(90)90693-9.
We have recently discovered that the mipA gene of A. nidulans encodes gamma-tubulin, a new member of the tubulin superfamily. To determine the function of gamma-tubulin in vivo, we have created a mutation in the mipA gene by integrative transformation, maintained the mutation in a heterokaryon, and determined the phenotype of the mutation in spores produced by the heterokaryon. The mutation is lethal and recessive. It strongly inhibits nuclear division, less strongly inhibits nuclear migration, and, as judged by immunofluorescence microscopy, causes a reduction in the number and length of cytoplasmic microtubules and virtually a complete absence of mitotic apparatus. We conclude that gamma-tubulin is essential for microtubule function in general and nuclear division in particular. Immunofluorescence microscopy of wild-type hyphae with affinity-purified, gamma-tubulin-specific antibodies reveals that gamma-tubulin is a component of interphase and mitotic spindle pole bodies. We propose that gamma-tubulin attaches microtubules to the spindle pole body, nucleates microtubule assembly, and establishes microtubule polarity in vivo.
我们最近发现,构巢曲霉的mipA基因编码γ-微管蛋白,它是微管蛋白超家族的一个新成员。为了确定γ-微管蛋白在体内的功能,我们通过整合转化在mipA基因中产生了一个突变,在异核体中维持该突变,并确定了由异核体产生的孢子中该突变的表型。该突变是致死性的且为隐性。它强烈抑制核分裂,对核迁移的抑制作用较弱,并且通过免疫荧光显微镜观察可知,它会导致细胞质微管数量和长度减少,几乎完全没有有丝分裂装置。我们得出结论,γ-微管蛋白总体上对微管功能至关重要,尤其对核分裂至关重要。用亲和纯化的、γ-微管蛋白特异性抗体对野生型菌丝进行免疫荧光显微镜观察发现,γ-微管蛋白是间期和有丝分裂纺锤体极体的一个组成部分。我们提出,γ-微管蛋白在体内将微管附着于纺锤体极体,引发微管组装,并确立微管极性。