GENE REGULATION IN DROSOPHILA PTERIDINE BIOSYNTHESIS

拟议研究的目的是对法规进行调查 黑腹果蝇GTP环水解酶(CH)的表达 催化蝶啶生物合成的第一步。这些实验 将是对蝶啶调节的长期研究的一部分 生物合成途径，特别强调对 蝶啶类物质产生的发育特异性。的一个重要特点 CH系统是非常广泛的表型变异阵列是容易的 可检测到的。我们已经确定了几个影响基因表达的基因座 陈氏其中之一，Pu基因座，似乎是 酵素。其他基因座的功能尚不清楚，但它们确实存在 不表现为CH的结构基因。我们检测到了几种突变 它们的影响是组织的或时间上特定的，其中一些在 “非结构”基因和一些在蒲氏基因中的基因。在建议的 实验是对CH活性在其中的精确组织的确定 和蛋白质被发现，EMS和Gram射线对Pu区的诱变 改善该地区的基因特征并扩大范围 CH表达的表型变种可由我们支配。我们还提议 进一步的CH生化分析，特别强调 该酶在不同组织和发育阶段表达的比较 各阶段。PU突变是由杂交不育引起的。重组 利用P元件和Copia克隆对Pu区进行DNA克隆 作为鉴定突变体Pu区中的同源插入片段的探针， 获得克隆形式的Pu区DNA。的限制映射 建议用野生型和突变型基因座的区域来定义功能 区域。利用转基因技术转化突变胚胎的研究 Pu区被认为是识别Pu基因座的一种手段。方法： 通过与PolA+RNA的同源性鉴定编码区 描述。功能分析中的生化和遗传学方法 对影响CH活性的非结构位点进行了讨论。

The purpose of the proposed research is the investigation of the regulation of expression of D. melanogaster GTP cyclohydrolase (CH), the enzyme catalyzing the first step in pteridine biosynthesis. These experiments will be part of a long-term study of the regulation of the pteridine biosynthetic pathway with particular emphasis on the control of the developmental specificity of pteridine production. An important feature of the CH system is that a very wide array of phenotypic variation is readily detectable. We have identified several loci that affect the expression of CH. One of these, the Pu locus, appears to be the structural gene for the enzyme. The functions of the other loci are as yet unknown, but they do not behave as structural genes for CH. We have detected several mutations that are tissue or temporally-specific in their effects, some of these in the "non-structural" loci and some in the Pu locus. Among the proposed experiments are a determination of the precise tissues in which CH activity and protein are found, EMS and Gramma-ray mutagenesis of the Pu region to improve the genetic characterization of the area and to expand the range of phenotypic variants of CH expression at our disposal. We also propose further biochemical analysis of CH with particular emphasis on the comparison of the enzyme expressed in different tissues and developmental stages. Pu mutations have been induced by hybrid dysgenesis. Recombinant DNA cloning of the Pu region is proposed using P element and copia clones as probes to identify homologous inserts in the Pu region of the mutants, and to obtain Pu region DNA in cloned form. Restriction mapping of the region in wild type and mutant loci is proposed to define the functional region. Transformation of mutant embryos by the injection of DNA from the Pu region is proposed as a means of identifying the Pu locus. Methods for identifying the coding region by its homology to polyA+ RNA are also described. Biochemical and genetic approaches to the analysis of function in the non-structural loci affecting CH activity are discussed.