Genetics of Neurospora

脉孢菌遗传学

• 批准号: 9728675
• 负责人: David Perkins
• 金额: $ 49万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-06-15 至 2003-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9728675&HistoricalAwards=false
• 关键词: Genetics; Neurospora

PERKINS 9728675 Neurospora is being used to investigate genetic problems that are not as readily approached with yeast or other organisms: (1) In a study of internuclear cis-trans position effects, progeny that are heterokaryotic for deficiencies of defined chromosome segments will be obtained from crosses heterozygous for translocations. These will be examined for impaired complementation between haploid nuclei, with the object of identifying segments and genes that specify nucleus-limited or nucleus-associated functions. The study is made possible by the existence of many well characterized chromosome rearrangements and the ability to obtain ascospores that are heterokaryotic for different products of the same meiosis. (2) The structure and content of a complex chromosome region that is responsible for meiotic drive will be examined using different Spore killer haplotypes in N. crassa and in the heterokaryotic species N. tetrasperma. New variants responsible for resistance to killing will be sought and characterized. The study is feasible because presence of a drive element is signaled visually by asci containing four black and four white ascospores. (3) Strains from natural populations will be examined for genetic polymorphisms at two molecularly sequenced vegetative incompatibility (het) loci, which govern the ability of nuclei to coexist in the same cytoplasm in a heterokaryon. This study of self-nonself recognition is made possible by the availability of insertional translocations that can be used to generate partial-diploid progeny heterozygous for each of the individual het genes. The filamentous fungus Neurospora serves as a modal for economically important fungi and for fungal plant and animal pathogens. It also continues to provide basic information on processes common to many higher organisms. Neurospora strains with cells that contain nuclei of two different genetic types, one with a deficient chromosome segment and the other with the corresponding active segement, will be used to identify genes whose functions are nucleus-limited or nucleus-localized. By using a series of defined segmental deficiencies, the experiments should reveal whether genes with completely or partially impaired internuclear complementation are widely distributed in the chromosomes. This noninvasive approach should provide new insights into cell organization. Make-up of the chromosomal Spore-killer complex is being examined. The direct effects of this selfish chromosomal DNA element are displayed visually in Neurospora in the pigmented ascospores of sexual hybrids. Genetic resolution of the complex should aid in understanding the evolutionary history and significance of similar meiotic drive elements in higher organisms. Neurospora is ideal for detecting vegetative incompatibility genes that are able to distinguish "self" from "nonself", thus controlling the ability of genetically different fungal cells to fuse and form a stable multinucleate heterokaryon. The frequency and nature of differences at two such gene loci are being examined in an extensive survey of Neurospora cultures from nature. The study is expected to increase understanding of the molecular basis of vegetative incompatibility and the significance of incompatibility for the organism.

神经孢子虫被用于研究酵母或其他生物不容易接近的遗传问题：(1)在核间顺式-反位效应的研究中，由于特定染色体片段的缺陷而具有异核性的后代将从杂交杂合易位中获得。这些将被检查单倍体核之间受损的互补，目的是识别指定核限制或核相关功能的片段和基因。由于存在许多具有良好特征的染色体重排，并且能够为同一减数分裂的不同产物获得异核子囊孢子，因此这项研究成为可能。(2)利用不同的孢子杀手单倍型，我们将在异核物种N. crassa和N. tetrasperma中研究一个负责减数分裂驱动的复杂染色体区域的结构和含量。新的抗杀变异体将被寻找和鉴定。这项研究是可行的，因为驱动元件的存在通过含有四个黑色和四个白色子囊孢子的子囊在视觉上发出信号。(3)来自自然种群的菌株将在两个分子测序的营养不相容（het）位点上进行遗传多态性检测，该位点控制细胞核在异核体中在同一细胞质中共存的能力。这种自我-非自我识别的研究是可能的插入易位的可用性，可用于产生部分二倍体杂合后代的每个单独的热基因。丝状真菌神经孢子菌是经济上重要的真菌和真菌植物和动物病原体的一种模式。它还继续提供许多高等生物共同过程的基本信息。神经孢子菌菌株的细胞含有两种不同的遗传类型的细胞核，一种具有缺陷的染色体片段，另一种具有相应的活性片段，将用于鉴定功能为核限制或核定位的基因。通过使用一系列明确的片段缺陷，实验将揭示核间互补完全或部分受损的基因是否广泛分布在染色体中。这种非侵入性方法应该为细胞组织提供新的见解。染色体孢子杀手复合体的组成正在被检查。这种自私的染色体DNA元素的直接影响在有性杂交的色素子囊孢子的神经孢子中直观地表现出来。该复合体的遗传解析有助于理解高等生物中类似减数分裂驱动元件的进化史和意义。神经孢子虫是检测能够区分“自我”和“非自我”的营养不相容基因的理想工具，从而控制遗传上不同的真菌细胞融合形成稳定的多核异核体的能力。两种基因位点差异的频率和性质正在对来自自然界的神经孢子菌培养物进行广泛调查。该研究有望增加对植物不亲和性的分子基础的认识和不亲和性对生物体的意义。