RUI: Regulation of the Pyrimidine Pathway in Plants

9318479 Slocum嘧啶核苷酸是DNA和RNA合成的前体，嘧啶衍生物是许多其他类型生物合成的活性中间体。 这些过程对所有生物体的生长和发育至关重要。 在植物中，对调节嘧啶生物合成的各种机制知之甚少，但大多数证据表明，重要的调节位点是途径的第一步和/或第二步，涉及酶氨甲酰磷酸合成酶（CPSase）和天冬氨酸转氨甲酰酶（ATCase）。 本研究的目的是研究植物中这些酶活性调节的各种分子机制。 这将通过克隆CPSase和ATCase的基因，纯化和生化表征酶蛋白，并产生CPSase和ATCase特异性抗血清来实现。 核酸和抗体探针将用于研究编码CPSase和ATCase的基因在不同植物组织中的表达以及对预期影响嘧啶生物合成的各种处理的响应。 通过在大肠杆菌中的功能互补，克隆了编码CPSase和ATCase的基因。colicarA/B-和pyrB-突变体。 这种方法已经允许在豌豆中成功分离编码功能性ATCases的两种不同基因（pyrB 1和pyrB 2）。 这种植物是第一个在其中不止一个pyrB基因已被证明的生物。 ***

9318479 Slocum Pyrimidine nucleotides are precursors of DNA and RNA synthesis and pyrimidine derivatives are activated intermediates in many other types of biosyntheses. These processes are of fundamental importance to the growth and development of all living organisms. In plants, little is known about the various mechanisms which regulate pyrimidine biosynthesis, but most evidence suggests that the important sites of regulation are the first and/or second steps of the pathway, involving the enzymes carbamoylphosphate synthetase (CPSase) and aspartate transcarbamoylase (ATCase). The objective of this research is to investigate the various molecular mechanisms regulating the activity of these enzymes in plants. This will be accomplished by cloning the genes for CPSase and ATCase, purifying and biochemically characterizing the enzyme proteins, and producing CPSase and ATCase-specific antisera. The nucleic acid and antibody probes will be used to investigate expression of the genes encoding CPSase and ATCase in different plant tissues and in response to various treatments that would be expected to impact pyrimidine biosynthesis. The genes encoding CPSase and ATCase will be cloned by functional complementation in E. coli carA/B- and pyrB- mutants. This approach has already permitted the successful isolation of two different genes (pyrB1 and pyrB2) encoding functional ATCases in pea. This plant is the first organism in which more than one pyrB gene has been demonstrated. ***