MECHANISM OF NUCLEAR AND CELL FUSION IN YEAST

描述：本提案侧重于对流程的剖析 在简单的真核生物酿酒酵母中的接合。一共有四个 这项建议的具体目的：1)调查 先前研究中确定的三个与核有关的基因 共轭过程中的收敛；2)函数的研究 涉及三个基因的交配和营养生长细胞 交配过程中的核融合；3)几个新基因的特征 参与细胞融合；以及4)鉴定受影响的新突变体 在两个亲本细胞中都需要的基因中 共轭关系。 第一个具体目标包括研究I类基因KAR3， KAR9和KIP2。这组基因编码的产物涉及到 在微管依赖的两个核的取向和运动 朝向彼此。这些研究的目的是将 蛋白质，确定它们可能与其他蛋白质的相互作用，以及 建立它们与微管的物理和功能关系。 第二个靶点是针对第二类核配子基因KAR5、KAR7、 和KAR8，其产物影响核膜的融合。这个 这里的目标是更准确地了解 由这组蛋白质催化。班级的可能要求 核分裂和核膜增殖的II基因 营养生长也将被评估。的最后两个部分 提案涉及影响两个亲本融合的FUS基因 细胞。申请人已分离出交配缺陷突变体(截然不同 从ste突变体中)识别在交配过程中起作用的新的FUS基因 特定于类型或独立的方式。 这第三个具体目标将努力澄清蛋白质是否以及如何 这组基因编码的基因可能会影响受精卵的早期步骤 细胞质膜融合等的形成和建立 细胞的极性。在之前的一段时间里，一些突变体 从双侧筛选中获得的细胞融合的核受精 只有当双方都携带突变时，才能观察到缺陷。自.以来 在早期筛查中分离的突变体数量表明，并不是所有的 基因已经饱和，该项目的最后一个具体目标是 要完成对从最近的大型 刻度屏幕。

DESCRIPTION: This proposal is focused on the dissection of the process of conjugation in the simple eukaryote S. cerevisiae. There are four specific aims of this proposal: 1) investigation of the function of three genes identified in previous studies as involved in nuclear congression during conjugation; 2) investigation of the function in mating and vegetatively growing cells of three genes implicated in nuclear fusion during mating; 3) characterization of several new genes involved in cell fusion; and 4) identification of new mutants affected in genes which are required in both parental cells for proper conjugation. The first specific aim encompasses studies of the class I genes KAR3, KAR9, and KIP2. The products encoded by this set of genes are involved in microtubule-dependent orientation and movement of the two nuclei towards each other. The aim of these studies is to localize the proteins, determine their possible interactions with other proteins, and establish their physical and functional relationship to microtubules. The second specific aim targets the class II karyogamy genes KAR5, KAR7, and KAR8 whose produts affect fusion of the nuclear envelope. The objective here is to understand more precisely the events that are catalyzed by this set of proteins. The possible requirement of class II genes for fission of nuclei and nuclear envelope proliferation during vegetative growth will also be assessed. The last two sections of the proposal touch on the FUS genes that affect fusion of the two parental cells. The applicant has isolated mating defective mutants (distinct from ste mutants) identifying new FUS genes that act either in a mating type-specific or independent manner. This third specific aim will strive to clarify if and how the proteins encoded by this group of genes may influence early steps of zygote formation such as fusion of the cytoplamsic membrane and establishement of cell polarity. During the previous period some of the mutants were obtained from bilateral screens in which karyogamy of cell fusion defects are observed only when both partners carry mutations. Since the number of mutants isolated in the earlier screens suggested that not all the genes have been saturated, the last specific aim of the project is to complete the analysis of mutants generated from a more recent large scale screen.