P1-Bh: A Maize Regulatory Gene Controlled by DNA Methylation

该项目将侧重于分子和遗传分析， Pl-Bh基因是一个控制紫色花青素合成的基因 玉米植株中的色素初步分析显示， 在核苷酸水平上，这个基因与野生的几乎相同， P1型基因，但与该基因不同，其高度甲基化。的 计划中的实验将验证这一假设，即甲基化的 P1-Bh DNA是导致 该等位基因的表达或改变的组织特异性，或 两者甲基化状态将使用基因组测序法测定。 测序方法，并将与基因水平相关 表达在轻度色素沉着和深色色素沉着的细胞， 植物和籽粒组织。染色质的可能改变 将通过DNase分析构型和/或蛋白质-DNA接触 脚印野生型和突变型基因都将 通过微粒轰击引入各种组织， 它们的表达与表型差异相关。我们将 寻找突变等位基因的遗传修饰剂， 确定修改是否是由于 P1-Bh等位基因的甲基化模式。 %%% DNA甲基化在基因调控中起着重要作用 在许多真核生物中表达，通常通过沉默基因 表情只有在少数情况下，它被证明会影响 表达的组织特异性。这些实验的结果 应有助于加强我们对这一问题和其他问题的理解 调节植物基因表达的表观遗传机制。 $$$

This project will focus upon the molecular and genetic analysis of Pl-Bh, a gene which controls the synthesis of purple anthocyanin pigments in the maize plant. Preliminary analysis indicates that at the nucleotide level, this gene is nearly identical to the wild- type Pl gene but, unlike that gene, is heavily methylated. The planned experiments will test the hypothesis that methylation of the Pl-Bh DNA is responsible for the variegated pattern of expression or the altered tissue-specificity of this allele or both. The methylation status will be determined using genomic sequencing methods and will be correlated with the level of gene expression in lightly pigmented and darkly pigmented cells from plant and kernel tissues. Possible alterations in chromatin configuration and/or protein-DNA contacts will be analyzed by DNase footprinting. Both the wild-type and mutant genes will be introduced into various tissues by microprojectile bombardment and their expression correlated with phenotypic differences. We will look for genetic modifiers of the mutant allele and it will be determined if the modification is a result of alterations in the methylation pattern of the Pl-Bh allele. %%% DNA methylation plays an important role in the regulation of gene expression in many eukaryotes, usually by silencing gene expression. In only a few cases has it been shown to influence the tissue-specificity of expression. The results of these experiments should serve to enhance our understanding of this and other epigenetic mechanisms which modulate plant gene expression. $$$