CONTROL OF GENE ACTIVITY AND ORGANELLE BIOGENESIS

微管在真核细胞中普遍存在，它们在细胞中形成不同的结构。 参与细胞形状、细胞运动、细胞内 有丝分裂和减数分裂的运动。 最精致的微管 细胞器是纤毛和鞭毛，在人类中， 呼吸道和女性生殖道，组织与高 癌症的发病率。纤毛功能障碍可引起呼吸和 生育问题该提案的长期目标是 了解微管多样性的分子机制， 特别强调纤毛的生物发生和功能。 关于微管蛋白一级序列作用的假设， 翻译后修饰，微管组织中心和 微管相关蛋白在产生微管多样性中的作用将 得到考验 低等真核生物，嗜热四膜虫，被用作 模型 该系统的优点包括相对小的微管蛋白 多基因超家族及其基因组学研究进展 能够进行基因置换的体细胞和胚细胞核的转化 和基因破坏。 这些方法将用于详细的 α-微管蛋白、β-微管蛋白和γ-微管蛋白功能的诱变分析 以及它们的二次修改。 一个新的功能 发现，异常多样的β-微管蛋白将被分析。基因 编码影响微管的微管相关蛋白 将克隆、测序及其蛋白产物在体内稳定 将被定性。 这些研究不仅应该揭示 正常纤毛生物发生和微管蛋白的功能，但也对 细胞骨架功能和细胞分裂之间的相互关系， 对正常发育至关重要且经常 在肿瘤细胞中异常。

Microtubules are ubiquitous in eukaryotic cells where they form diverse organelles involved in cell shape, cell motility, intracellular movements mitosis and meiosis. Among the most elaborate microtublar organelles are cilia and flagella, which, in humans, are found in the respiratory tract and the female reproductive tract, tissues with high incidences of cancer. Ciliary dysfunction can cause respiratory and fertility problems. The long term goals of this proposal are to understand the molecular mechanisms underlying microtubule diversity, with particular emphasis on the biogenesis and function of cilia. Hypotheses concerning the role of tubulin primary sequences, posttranslational modifications, microtubule organizing centers and microtubule-associated proteins in generating microtubule diversity will be tested. The lower eukaryote, Tetrahymena thermophila, is used as a model. Advantages of this system include the relatively small tubulin multigene superfamily and the recent development of methods for mass transformation of somatic and germinal nuclei enabling gene replacement and gene disruption. These methods will be used for a detailed mutagenic analysis of the function of alpha-and-beta-and gamma-tubulin and of their secondary modifications. The function of a newly discovered, unusually diverse beta-tubulin will be analyzed. Genes encoding microtubule associated proteins that affect microtubule stability in vivo will be clones, sequenced and their protein products will be characterized. These studies should not only shed light on normal cilia biogenesis and the function of tubulins, but also on interrelationships between cytoskeletal functions and cell division, events that are critical for normal development and that are frequently abnormal in neoplastic cells.