Regulation of Photosynthetic Electron Transport Genes in Chlamydomonas Chloroplasts

RNA稳定性的调节在基因表达中起着重要的作用，但其中涉及的机制却知之甚少。这项建议涉及调节高等植物叶绿体mRNAs在细胞器生物发生过程中差异周转的分子和生化因素。重点研究了在叶绿体mRNAs的3‘端发现的高度保守的反向重复序列(IR)。叶绿体3‘IRS与蛋白质结合，在体外作为RNA加工元件和稳定性决定因素。我建议调查IR处的蛋白质：RNA关联是否参与调节叶绿体RNA周转。这些研究将包括3‘IR序列的突变和RNA结合蛋白的纯化这些蛋白将用于功能分析和产生抗体，这些抗体将用于研究蛋白质浓度的发育变化，并最终分离编码它们的基因。通过分析叶绿体中的核糖核蛋白颗粒(RNP)来探索叶绿体mRNAs的体内结构，并通过体内标记来定量它们的半衰期。我们的长期目标是建立一个模型，用于控制叶绿体基因稳定性的发育，并确定核基因产物是否是影响叶绿体基因衰退的因素之一。

Regulation of RNA stability plays an important role in gene expression, but the mechanisms involved are poorly understood. This proposal addresses molecular and biochemical factors that regulate differential turnover of higher plant plastid mRNAs during organelle biogenesis. Emphasis is placed on the study of highly conserved inverted repeat (IR) sequences found at the 3' ends of plastid mRNAs. Plastid 3' IRs bind proteins, and act as RNA processing elements and stability determinants in vitro. I propose to investigate whether protein:RNA associations at the IR are involved in the regulation of plastid RNA turnover. These studies will entail mutagenesis of 3' IR sequences, and purification of RNA-binding proteins These proteins will be used in functional assays and to raise antibodies, which will be used to investigate developmental changes in protein concentrations, and eventually in isolation of the genes encoding them. The in vivo structure of plastid mRNAs will be probed by analyzing ribonucleoprotein particles (RNPs) from plastids, and their half lives will be quantified by in vivo labeling. The long-term objectives are to develop a model for the developmental control of plastid mRNA stability, and to determine if nuclear gene products are among the factors that influence plastid mRNA decay.***//