COMPONENTS REQUIRED FOR ASYMMETRIC CELL GROWTH IN FUNGUS

细胞不对称分裂是发育和形成模式所必需的 在多细胞生物体中的形成。在许多生物中，第一个 合子分裂是不对称的，导致子代细胞 不同的胚胎命运。尽管对受精卵的实验操作 在许多系统中是困难的，褐藻Fucus distichus为 用于解剖不对称性发展的优秀模式生物 无极祖细胞无极祖细胞肌动蛋白微丝是 岩藻的不对称生长。最近的实验已经导致了一种模型 在岩藻中轴的固定和发育，其中轴的形成 结构和功能相似的稳定络合物(ASC) 哺乳动物的局部粘连是必需的。构成ASC的因素 尚未在岩藻属或高等植物中发现。为了 识别结合肌动蛋白的Fucus ASC组件，双杂交筛选将 被执行。此外，Fucus的cDNA文库还将用于 补充酿酒酵母突变体的细胞骨架和形态 缺陷。然后将对筛查中确定的因素进行肌动蛋白测试 体外结合活性。针对肌动蛋白结合产生的抗体 蛋白质将用于原位定位，并将被显微注射 进入受精卵发育阶段，观察其对受精卵建立的影响 Fucus极性的。大黄鱼肌动蛋白结合蛋白的鉴定 Fucus及其在不对称形态发生中的作用表征 将为肌动蛋白细胞骨架在受精卵中的作用提供一个模型 复杂的多细胞生物体的发展。

Asymmetric cell division is required for development and pattern formation in multicellular organisms. In many organisms, the first zygotic division is asymmetric, resulting in daughter cells with different embryonic fates. Although experimental manipulation of zygotes in many systems is difficult, the brown alga Fucus distichus provides an excellent model organism for dissecting the development of asymmetry from an apolar progenitor cell. Actin microfilaments are essential for asymmetric growth in Fucus. Recent experiments have led to a model for axis fixation and development in Fucus in which formation of an axis stabilizing complex (ASC) with structural and functional similarity to mammalian focal adhesions is required. The factors comprising the ASC have not yet been identified in Fucus or in higher plants. In order to identify Fucus ASC components that bind actin, a two-hybrid screen will be performed. In addition, a Fucus cDNA library will be used to complement S. cerevisiae mutants with cytoskeletal and morphological defects. Factors identified in the screens will then be tested for actin binding activity in vitro. Antibodies raised against the actin-binding proteins will be used for localization in situ, and will be microinjected into developing zygotes to observe the resulting effects on establishment of Fucus polarity. The identification of actin-binding proteins from Fucus and the characterization of the roles in asymmetric morphogenesis will provide a model for the role of the actin cytoskeleton in zygotic development in complex multicellular organisms.