Synthesis, Organization and Function of Ribonucleic Acid

本研究的总体目标是阐明在转录、RNA加工、RNA周转和翻译水平上调控遗传表达的机制。人们的注意力集中在小鼠编码核糖体结构蛋白（rp’s）和免疫球蛋白（ig’s）的基因上。对于rp基因，我们正在(i)分析其独特的等能启动子，（ii）研究内含子对mRNA的稳定和细胞内转运的重要性，以及（iii）研究rp mRNA的翻译控制。未来对这些基因的研究将包括对rp转录因子及其编码基因的表征，阐明寡聚嘧啶帽序列和内部启动子元件的作用，研究各种启动子元件之间的相互作用，分析无内含子转录物的核内周转。以及限制rp mrna结合核糖体能力的结构特征的定义。对于ig基因，我们正在(i)研究通过选择性RNA加工对重链mRNA产生的调控，（ii）表征kappa基因启动子元件之间的相互作用，以及（iii）确定kappa增强子和染色质重组在kappa基因表达的发育调控中的作用。未来对这些基因的研究将包括对早期和晚期淋巴细胞的整体切割-聚腺苷化和剪接效率的比较，寻找决定JH-Cmu和JH-Cdelta剪接相对效率的参数，表征一种新的kappa启动子元件及其蛋白质配体，克隆编码该配体的基因，以及赋予kappa基因增强子独立表达的遗传片段的定位。这些研究的结果不仅应该增加对rp和ig基因如何工作的认识，而且应该揭示适用于具有类似性质的其他基因的一般原理。所进行的实验将继续遵循将基因表达为功能性蛋白质所需的过程。这些过程是大多数生物体的基础。这些结果将有助于我们对基因表达的理解，并适用于广泛的生物学问题。

The overall goal of this research is to elucidate mechanisms that regulate genetic expression at the levels of transcription, RNA processing, RNA turnover and translation. Attention is focused on the mouse genes encoding ribosomal structural proteins (rp's) and immunoglobulins (ig's). For the rp genes, we are (i) analyzing their distinctive equipotent promoters, (ii) studying the importance of introns for stabilization and intracellular transport of mRNA, and (iii) studying the translational control of rp mRNA. Future studies of these genes will include a characterization of rp transcription factors and the genes encoding them, elucidation of the roles of the oligopyrimidine cap sequence and the internal promoter elements, studies of the interactions between the various promoter elements, an analysis of the intranuclear turnover of intronless transcripts, and definition of the structural features that limit the capacity of rp mRNAs to bind ribosomes. For the ig genes, we are (i) studying the regulation of heavy chain mRNA production by alternative RNA processing, (ii) characterzing the interplay between elements of kappa gene promoters, and (iii) defining the role of the kappa enhancer and chromatin restructuring in the developmental regulation of kappa gene expression. Future studies of these genes will include a comparison of overall cleavage-polyadenylation and splicing efficiencies in early and late stage lymphocytes, a search for the parameters that determine the relative efficiencies of JH-Cmu and JH-Cdelta splicing, characterization of a novel kappa promoter element and its protein ligand, cloning of the gene encoding this ligand, and localization of the genetic segment that confers enchancer-independent expression of the kappa gene. The results of these studies should not only increase knowledge of how rp and ig genes work, but should also reveal general principles that apply to other genes with similar properties. The experiments performed will continue to follow the processes needed to get a gene expressed as a functional protein. These processes are fundamental for most organisms. The results will aid in our understanding of gene expression and be applicable to a wide range of biological problems.