MOLECULAR GENETICS OF SULFUR METABOLISM IN NEUROSPORA

粗枝脉孢菌的一个主要硫调节系统将是 在分子水平上的特征是使用了一种基因- 一组明确的反式作用调控基因和一个结构基因 他们控制着一切。这些研究的目的是达成一种理解 的监管互动和整体组织 多基因网络。分析也将导致更好的 了解细胞如何调节其硫磺状态以及 人类先天的新陈代谢错误。该系统由 Cys-3+调控基因(正调节基因)，三个负调控基因 调控基因(命名为scon-1+、scon-2+、scon-3+)，以及 芳基硫酸酯酶结构基因(ars+)。Cys-3+和Ars+基因 已经被克隆了。SCON+负性调控基因 将在基因和分子水平上进行分析。上位性试验 和异核体的功能将有助于建立 控制的层次结构。至少有一个SCON+基因将是 通过同胞选择克隆。所有克隆的基因都将完全 具有特征的(即它们的序列、转录本和基因 产品)。详细的研究将使用克隆的基因来确定 该基因的转录和转录后调控 多基因系统。转录调控将得到确认 通过核转录分析。稳态和动态信使核糖核酸 还将进行测量。转录后控制将 通过构建基因融合后的基因来检测 更换和化验。这些信使核糖核酸分析将在 现有的和处于不同生长状态下的调控突变体 条件(即，硫磺解压和重压) 可以评估遗传和新陈代谢的影响。潜在的顺位- 调控序列将在体外被诱变，并重新- 通过基因替换引入，以便直接确认和 测试它们的功能。监管基因产品将是 在体外生产，使用凝胶迁移率分析和DNA 足迹进一步证实了调控序列。这个 半胱氨酸(代谢效应器)与 调控基因产物将通过平衡透析法进行检测。 预测一个(或多个)调控基因产物 将展示DNA和/或半胱氨酸的结合特性 直接测试。如果时间允许，功能域的研究将在 调控基因产物将在体外进行 两种基因编码序列在体内的变化 并进行体外功能评估。

A major sulfur regulatory system in Neurospora crassa will be characterized at the molecular level by using a genetically- defined set of trans-acting regulatory genes and a structural gene they control. The studies are aimed at achieving an understanding of the regulatory interactions and overall organization of this multigene network. The analysis will also lead to a better understanding of how a cell regulates its sulfur status and of human inborn errors of metabolism. The system consists of the cys-3+ regulatory gene (positive regulator), three negative regulatory genes (designated scon-1+, scon-2+, scon-3+), and the arylsulfatase structural gene (ars+). The cys-3+ and ars+ genes have been have been cloned. The scon+ negative regulatory genes will be analyzed on a genetic and molecular level. Epistasis tests and function in heterokaryons will aid in establishing the hierarchy of control. At least on of the scon+ genes will be cloned by sib selection. All the cloned genes will be fully characterized (i.e., their sequence, transcripts, and gene products). Detailed studies will use the cloned genes to determine the transcriptional and post-transcriptional controls in this multigene system. Transcriptional regulation will be confirmed by nuclear transcription assays. Steady state and kinetic mRNA measurements will also be done. Posttranscriptional control will be detected by constructing gene fusions followed by gene replacement and assay. These mRNA analyses will be done with the regulatory mutants available and under different growth conditions (i.e., sulfur derepressing and repressing) so that both genetic and metabolic effects can be assessed. Potential cis- regulatory sequences will be mutagenized in vitro and re- introduced by gene replacement in order to directly confirm and test their function. The regulatory gene products will be produced in vitro and using gel mobility assays along with DNA footprinting further confirm the regulatory sequences. The interaction of cysteine (the metabolic effector) with the regulatory gene products will be examined by equilibrium dialysis. The prediction that one (or more) of the regulatory gene products will demonstrate DNA and/or cysteine binding properties will be directly tested. If time allows, the study of functional domain in the regulatory gene products will be carried out by the in vitro alteration of the genes coding sequences followed by both in vivo and in vitro assessment of function.