RUI: Mutational Analysis of Gene Regulation in Maize

Alleman 9603747 r是玉米中四个基因座之一，通过其产物螺旋-环-螺旋转录因子调节花青素生物合成途径中基因的表达。R决定了花青素在发育过程中沉积的时机和组织特异性。通过分析影响单个转录单位r等位基因调控的突变体，首席研究者为研究r的组织特异性奠定了基础。R-st复合体的R(SC)基因规定了籽粒糊粉层和幼苗的胚芽鞘和盾节的色素沉着。正在进行的研究已经确定了一个493bp的序列(B‘NOT)，它位于SC调节区的可能的增强子元件中。在某些异等位基因组合中，该片段可以通过建议的与移位的近端区域的基因转换事件来规则地删除，以产生增强的SC表达SC|P(增强)。或者，B‘NOT元件或周围的增强子区域可以被转座元件DS突变打乱。在这个区域内的DS插入可能通过破坏正常结构域边界，当它们在一个方向时轻微阻止色素沉着，或者当它们在另一个方向时完全阻止。上游DNA序列DS插入突变体及其衍生物，以及一组代表强籽色等位基因(SC)扰动的三个变异等位基因，以确定一类r等位基因的结构与功能之间的关系。利用这一DNA序列分析，将确定SC|P(增强)衍生物的产生机制是通过基因转化。染色质结构也将被分析为一类色素被条件阻断的等位基因。只有r等位基因不同的玉米小种集合将通过表型分析和DNA凝胶印迹分析进行筛选，以定位其他相关的SC型等位基因。为了定位参与发育基因表达的其他区域，将对基因进行区域筛选。这些研究构成了对高等植物中控制基因表达的调控序列的详细遗传解剖，对于了解基因在植物发育过程中是如何调控的具有重要意义。通过使用突变，其中起始材料是一系列变异的等位基因和单个转录单位r等位基因，决定了同一组织中的色素沉着。玉米组织特异性调控元件的鉴定对于对这一重要的农艺物种进行基因工程是至关重要的。

Alleman 9603747 r is one of four loci in maize that regulates the expression of the genes in the anthocyanin biosynthetic pathway through the function of its product, helix-loop-helix transcription factor. r determines the timing and tissue-specificity of anthocyanin deposition during development. By analyzing mutants affecting the regulation of single transcriptonal unit r alleles, the principal investigator has established the basis for investigating tissue-specificity of r. The R(Sc) gene of the R-st complex specifies pigmentation in the aleurone layer of the kernel and the coleoptile and scutellar node of the young seedling. On going studies have identified a 493 bp sequence (B' not) which is located in putative enhancer element in the Sc regulatory region. This segment can be regularly deleted in certain heteroallelic combinations via a proposed gene conversion event with a displaced proximal region to produce enhanced Sc expression Sc|P(enhanced) . Alternatively, the B'not element or the surrounding enhancer region can be disrupted by transposable element Ds mutagenesis. Ds insertions within this region block pigmentation slightly when they are in one orientation or totally when they are in the other orientation, possibly by disrupting the normal domain boundary. The upstream DNA sequence Ds insertional mutants, their derivatives, and a selected group of three variant alleles representing perturbation in strong seed color alleles (Sc) to determine the relationship between the structure and function of one class of r alleles. Using this DNA sequence analysis, it will be determined the mechanism for Sc|P(enhanced) derivative production is by gene conversion. Chromatin structure will also be analyzed for a class of alleles for which pigment is conditionally blocked. An established collection of races of maize differing only by the r allele will be screened using a phenotypic assay and eventually DNA gel blot analysis to locate other related Sc-type alleles. A genetic screen will be region in order to localize other regions that are involved in developmental gene expression. The studies constitute a detailed genetic dissection of the regulatory sequences controlling gene expression in higher plants and are of fundamental importance for understanding how genes are regulated during plant development. By using mutagenesis in which the starting material is a series of variant alleles and single transcriptional unit r alleles determining pigmentation in the same that tissue. The identification of tissue-specific regulatory elements in maize is crucial in order to genetically engineer this agronomically important species.