Genetic Control of Nutrition Starvation in Yeast

描述(申请人提供)：这项研究的目标是确定控制丝状化的酿酒酵母中的调节电路，丝状化是即使在致病和非致病真菌中的关键形态发生。我们在酿酒酵母Sigma菌株中的缺失文库与S288c中的参考文库相比，能够全面评估导致两个不同实验室菌株中同一突变的不同丝状化和生存表型的遗传机制。这个问题也是人类遗传学家在研究复杂疾病特征的遗传性时所面临的问题。对丝化/黏附特性的分析表明，在IME4基因的催化下，m6A对mRNA的修饰是控制进入丝化或减数分裂途径的决定的关键转录后事件。实验将确定这种M6A修饰的功能，以及该标记的消失是由于去甲基化还是特定信使降解所致。在一个菌株(Sigma)中激活丝状基因的信号转导途径(丝状MAPK途径，fMAPK)在另一个菌株(S288c)中不是必需的，它已经进化出绕过这一途径的必要性的多态。对这种可供选择的丝状化途径的分析将揭示这些多态发展的潜在网络。特别重要的是两个顺式作用的非编码RNA，PWR1和ICR1，在Sigma中已被证明是控制邻近FLO11基因表达的顺式作用开关，这是丝状化所需的。实验是为了确定这些非编码RNA是否参与S288c中FLO11的表达，其中一组不同的反式作用因子激活FLO11。这些实验将为ncRNA调控在物种中的普遍存在提供新的线索。我们的全基因组比较也发现了条件性必需基因，这些基因的功能是在一个菌株中生存所必需的，但不是 另一个。对导致致命性抑制的遗传差异的分析提出了 染色体外元件(线粒体DNA)和dsRNA与染色体多态相互作用导致变异的可能性。这些核/细胞质相互作用的发现为复杂性状的分析增加了一个意想不到的维度。

DESCRIPTION (provided by applicant): The goal of this research is to determine the regulatory circuits in S. cerevisiae that control filamentation, a key morphogenetic even in pathogenic and non-pathogenic fungi. Our deletion library in the S. cerevisiae Sigma strain, when compared with the reference library in S288c, enables a comprehensive assessment of the genetic mechanisms leading to different filamentation and viability phenotypes for the same mutation in two different laboratory strains. This problem is the same one confronting human geneticists tackling the heritability of complex disease traits. The analysis of the filamentation/adhesion trait, which is important for the ability of fungi to adhere to medical devices, revealed that a m6A modification of mRNA, catalyzed by the IME4 gene, is a key post-trancriptional event that controls the decision to enter the filamentation or meiotic pathway. Experiments will determine the function of this m6A modification and whether the disappearance of the mark is due to demethylation or specific messenger degradation. The signal transduction pathway (the filamentation MAPK pathway, fMAPK) that activates filamentation genes in one strain (Sigma) is not required in the other (S288c), which has evolved polymorphisms that bypass the necessity for this pathway. The analysis of this alternative filamentation pathway will reveal the underlying network within which these polymorphisms develop. Of particular importance are two cis-acting non-coding RNAs, PWR1 and ICR1, that have been shown in Sigma to be a cis-acting toggle controlling the expression of the adjacent FLO11 gene, which is required for filamentation. Experiments are designed to determine whether these non-coding RNAs are involved in FLO11 expression in S288c, where a different set of trans- acting factors activate FLO11. These experiments will shed new light on the ubiquity of ncRNA regulation within a species. Our genome-wide comparison also identified conditionally essential genes, genes whose function is required for viability in one strain but not the other. The analysis of the genetic differences that lead to suppression of lethality has raised the possibility that extra-chromosomal elements (mitochondrial DNA) and dsRNA interact with chromosomal polymorphisms to cause variation. The discovery of these nucleo/cytoplasmic interactions adds an unanticipated dimension to the analysis of complex traits.