KARYOGAMY AND CENTROSOME-DEPENDENT PROCESSES IN BUDDING YEAST

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。所列机构为中心机构，不一定是研究者机构。在交配过程中，S.酿酒酵母细胞对交配信息素梯度的反应是以极化方式彼此相向生长。两个细胞相遇后，它们的细胞壁在接触区域降解，它们的质膜融合成单个细胞。最终，两个细胞核通过微管连接，微管来自微管组织中心（MTOC），即，主轴杆体。细胞核通过微管马达驱动的过程相互吸引。核膜特征性地在纺锤体极体附近融合，产生单个二倍体核。因此，几种基本的生物细胞过程，例如，该模型系统较好地描述了细胞极化、膜融合、核运动和微管组织。纺锤体极体及其相关的微管在整个核融合中特别重要，因为MTOC对核迁移，融合和极性至关重要。先前的研究表明，Kar 9 p、Kar 3 p和Kar 1 p蛋白（都是MTOC的组成部分）是完成核配所必需的。另外，Kar 2 P。Kar 5 p、Kar 7 p和Kar 8 p都是核膜的一部分，在两个SPB紧密并置后核膜融合所需。电子显微镜，特别是半厚切片的电子断层扫描，已被证明是非常宝贵的研究MTOC相关的过程，因为它允许重建整个微管阵列从MTOC在一个单一的细胞。因此，应用电子断层扫描的过程中的核配提供了以前未知的过程中有关的参与MTOC在这个系统中的见解。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. During mating, S. cerevisiae cells respond to gradients of mating pheromone by growing toward one another in a polarized fashion. After two cells have met, their walls are degraded in the region of contact and their plasma membranes fuse to make a single cell. Eventually, the two nuclei become connected by microtubules that emanate from the microtubule organizing centers (MTOCs), i.e., the spindle pole bodies. The nuclei are drawn toward one another by a microtubule motor-driven process. The nuclear envelopes characteristically fuse in the vicinity of the spindle pole bodies, giving rise to a single diploid nucleus. Accordingly, several basic biological cell processes, e.g., cell polarization, membrane fusion, nuclear movement and microtubule organization are well represented by this model system. The spindle pole bodies and their associated microtubules are of particular importance throughout karyogamy, as the MTOCs are crucial to nuclear migration, fusion and polarity. Previous work has shown that the proteins Kar9p, Kar3p and Kar1p (all of which are components of the MTOCs) are required for karyogamy to be completed. Additionally, Kar2p. Kar5p, Kar7p and Kar8p, which are all part of the nuclear envelope, are required for nuclear membrane envelope fusion after the two SPBs have come into close apposition. Electron microscopy, and specifically electron tomography of semi-thick sections, has proven to be invaluable for studying MTOC-related processes, because it permits the reconstruction of entire microtubule arrays from MTOCs within a single cell. As such, the application of electron tomography to the process of karyogamy should provide insights into previously unknown processes concerning the involvement MTOCs in this system.