Molecular Cell Biological Study on Calcium Signaling

我们研究的一个目标是阐明芽殖酵母酿酒酵母交配过程中Ca^<2+>信号传导的分子机制。近年来的研究发现，酵母MID 1基因产物（Mid 1）是交配过程中钙离子内流所必需的，并且发现Midi是一个Ca^2+可透过的阳离子通道。在这项研究中，我们对mid 1 -1等位基因显示合成致死性的突变进行了筛选。合成致死性提供了体内证据，表明两种基因产物在物理上相互作用或在重叠途径中发挥作用。我们可以分离出40个合成致死突变体，并分离出一个赋予合成致死性的基因。在另一个项目中，我们制作了突变的midi基因，其中假定的跨膜H2中的谷氨酸被其他氨基酸取代，现在正在研究这些突变的Mid 1蛋白的通道活性。我们还分离了7个midi突变等位基因，希望我们可以确定重要的氨基酸Mid 1通道的功能。

A goal of our research is to unravel molecular mechanisms of Ca^<2+> signaling during the mating process in the budding yeast Saccharomyces cerevisiae. The revious studies have revealed that the yeast MID1 gene product (Mid1) is required for calcium influx during the mating process, and found that Midi is a Ca^<2+>-permeable cation channel. In this study, we did a screen for mutations showing synthetic lethality with the mid1-1 allele. Synthetic lethality provides in vivo evidence that two gene products physically interact with each other or function in overlapping pathways. We could isolate forty synthetic lethal mutants and isolated a gene that conferred synthetic lethality. In another project, we made mutant midi genes, in which glutamate in the putative transmembrane H2 was substituted by other amino acids, and are now investigating channel acivities of these mutant Mid1 proteins. We also isolated seven midi mutant alleles, with the hope that we can identify amino acids important for the function of the Mid1 channel.