B Mating-type Specificities and Phermones in Schizophyllum

9423994 Raper：这项研究的目的是了解一个简单的真核生物如何在调节交配和发育方面区别于许多非自我。本研究的具体目的是揭示蘑菇型真菌裂殖酵母中多等位基因B交配型基因启动性发育的分子机制。B基因位于两个连锁的基因座上，即B(和B()，每个基因在世界范围内的人群中都有九种不同的特异性。交配配对必须在B(或B()处是异等位基因，才能相容：36种不同特异性的配对中的任何一种都会导致启动相同的发育途径。这怎麽可能？最近对B(1)的克隆和测序揭示了与在其他真菌中发现的类似的信息素和信息素受体的基因；然而，所有先前描述的真菌系统只拥有这些基因的两个等位版本。这可能是一个独特的信息素和信息素受体基因组成的系统，它作为性形态发生的主要调节因子。通过对B(3和B(2)基因座的突变解剖，已经得到了与性形态发生有关的其他连锁基因的证据。据推测，这些其他基因在信息素反应途径的下游作用，影响B调节发育的特定步骤。本项目的重点是通过表征B(3和B(2)基因座的功能遗传成分来检验这些假说。作为与两个欧洲实验室合作努力的一部分，这些基因将与B(1和B(1)基因座进行比较。定义B(和B()特定特性的遗传元件的数量和种类是通过DNA测序和DNA介导法转化裂殖酵母的标准技术来确定的。相关基因编码区的初步分析将通过体外诱变和cDNA测序获得。这些基因座中现有的缺失突变将被用来分离和表征在B调节途径中影响特定发育事件的基因。通过使用野生型B(3-B(2个)区域内的一组重叠克隆作为探针来确定突变的DNA与祖代DNA的差异，将识别感兴趣的基因。突变菌株将被用作转化受体，以测试野生型基因的功能。初步证据表明，公社自体/非自体识别的B基因调控是基于一个配体/受体系统，该系统类似于在广泛的生物体中调节细胞间的通讯和分化的那些已知的系统。这项研究将利用一个独特的机会来定义在遗传上可获得的生物体中似乎有多个版本的此类分子的遗传决定因素。*？？

9423994 Raper The aim of this research is to understand how a simple eukaryote distinguishes itself from many nonselves in regulating mating and development. The specific objective is to discover the molecular mechanism by which the multiallelic B mating-type genes trigger sexual development in the mushroom-type fungus Schizophyllum commune. The B genes reside in two linked loci, B( and B(, each of which has nine different specificities in the world-wide population. A mating pair must be heteroallelic at either B( or B( to be compatible: any of 36 possible pairings of different specificities at either locus results in initiation of the identical developmental pathway. How is this possible? The recent cloning and sequencing of B(1 has revealed genes for putative pheromones and a pheromone receptor similar to those found in other fungi; all previously described fungal systems, however, possess only two allelic versions of such genes. It is likely that the basis for multispecificity of the B mating-type loci in S. commune is a unique system of multiple pheromone and pheromone receptor genes which act as master regulators of sexual morphogenesis. Evidence for other linked genes involved in specific events of sexual morphogenesis has been produced by a mutational dissection of the B(3 and B(2 loci. It is hypothesized that these other genes act downstream in a pheromone response pathway to affect particular steps in B-regulated development. The focus of this project is to test these hypotheses by characterizing the functional genetic components of the B(3 and B(2 loci. These will be compared with the B(1 and B(1 loci as part of a collaborative effort with two European laboratories. The number and kind of genetic elements that define given specificities of B( and B( is being determined by using standard techniques of DNA sequencing and DNA-mediated transformation of Schizophyllum. Preliminary analyses of the coding regions of relevant genes will be obtained by in vitro rnutagenesis and cDNA sequ encing. The existing deletion mutations within the loci will be used to isolate and characterize genes that affect specific developmental events in the B-regulated pathway. Genes of interest will be identified by using a set of overlapping clones within the wild-type B(3 - B(2 region as probes to determine differences in mutated versus progenitor DNA. Mutant strains will be used as transformation recipients to test for function of the wild-type genes. %%% Preliminary evidence suggests that B gene regulation of self/nonself recognition in S. commune is based on a ligand/receptor system similar to those known to regulate cell-to-cell communication and differentiation in a broad range of organisms. This study will take advantage of a unique opportunity to define the genetic determinants of what appear to be multiple versions of such molecules in a genetically accessible organism. *** ??