Molecular Specificity of Pheromone/Receptor Interactions for Mating in Schizophyllum

这项研究的总体目标是了解一个简单的真核生物如何在调节交配和发育方面将自己与许多其他非自我区分开来。 具体目的是阐明B交配型基因触发木腐蘑菇裂褶菌有性发育的分子机制。 B基因位于两个连锁基因座Ba和B B，在世界范围的人群中，每个基因座都有9个不同的版本或特异性。 交配对必须在Ba或Bb上不同才能兼容。 对每个位点的两个特异性的分析揭示了与其他真菌中发现的信息素和信息素受体相似的基因。 每个位点包含一个信息素受体基因和几个信息素基因。 这种信息素和受体基因的多样性似乎是高等担子菌所特有的。迄今为止的分子分析表明，信息素或受体分子中的一个或两个氨基酸的变化就可以与配偶识别和性信号的转换相关。 本研究主要分为三个部分：1）对各种天然的和先前产生的信息素和受体的突变体进行序列和功能的全面比较，以确定信息素/受体相互作用相关位置的氨基酸残基。 2)利用定点突变和DNA介导转化的方法，在地木耳中测试在可能与信息素/受体识别有关的特定位点上取代各种氨基酸对每种类型分子的影响。 3)利用最近在酿酒酵母中组装的异源球体应答报告系统产生新的S.公社信息素和受体，并有效地表征其对配体/受体相互作用的影响。

The overall aim of this research is to understand how a simpleeukaryote distinguishes itself from many other nonselves in regulatingmating and development. A specific objective is to elucidate the molecularmechanism by which the B mating-type genes trigger sexual development inthe wood rotting mushroom Schizophyllum commune. The B genes are in twolinked loci, Ba and Bb, each of which has nine different versions, orspecificities, in the world-wide population. A mating pair must bedifferent at either Ba or Bb to be compatible. Analyses of two specificities ofeach locus has revealed genes for pheromones and pheromone receptors similar to those found in other fungi. Each locus contains a single pheromonereceptor gene and several pheromone genes. This multiplicity of pheromoneand receptor genes appears to be unique to the higher basidiomycete fungi.Molecular analyses to date indicate that as few as one or two aminoacid changes in either a pheromone or receptor molecule can be correlatedwith a switch in mate recognition and signaling of sexual. The proposedresearch is divided into three parts: 1) A comprehensive comparison ofsequence and function for a variety of natural and previously generatedmutant variants of pheromones and receptors to identify amino acid residuesin positions relevant to pheromone/receptor interactions. 2) Test theeffects of substituting various amino acids at specific sites that could berelevant to pheromone/receptor recognition for each type of molecule, usingthe methods of site-directed mutagenesis and DNA-mediated transformation inS. commune. 3) Exploit a recently assembled heterologouspheromone-response reporter system in the yeast Saccharomyces cerevisiae togenerate new mutant variants of S. commune pheromones and receptors andefficiently characterize their effects on ligand/receptor interaction.