POLY-A FUNCTION & METABOLISM IN SACCHAROMYCES CEREVISIAE

基因是如何通过改变其新陈代谢来进行差异调控的 成熟的信使核糖核酸是分子生物学的一个关键问题。潜在的要点 调节包括核质信使核糖核酸的转运、信使核糖核酸的稳定性和 MRNA翻译效率。考虑了信使核糖核酸的聚(A)尾 对这些过程中的每一个都很重要，但对Poly没有明确的了解 (A)存在尾部函数。这项工作的长期目标是 分析Poly(A)在信使核糖核酸代谢中的作用(S)并了解其如何 它或与之结合的蛋白质的修饰，即聚(A)结合 蛋白质，可以影响这种新陈代谢。有了这样的理解，潜在的 多聚(A)依赖的信使核糖核酸代谢步骤的改变 可以研究细胞感染或转化。 这项工作的最初目标是鉴定酵母菌的基因 影响聚(A)合成、包装和降解的酿酒酵母。 这些基因包括编码聚(A)聚合酶的基因，聚(A)结合 蛋白质和七个基因(spb1-spb7)，它们在突变时允许细胞 生活中没有必要的聚(A)结合蛋白。其中之一，SPB2， 编码核糖体蛋白L46，另一种编码蛋白质SPB4 它与真核启动因子4a高度同源，并且是 可能是一种RNA解旋酶。这些基因突变对胰岛素样生长因子的影响 体内信使核糖核酸的转运、聚(A)和信使核糖核酸的稳定性以及信使核糖核酸的翻译 接受检查。一种可靠的聚(A)体外降解试验 在体内复制这些突变的效果将会得到发展。这 检测将检测Poly(A)尾巴和 这将是一个研究的模型系统 信使核糖核蛋白结构及其对mRNA稳定性的影响。

How genes are differentially regulated by altering the metabolism of their mature mRNA is a key question in molecular biology. Potential points of regulation include nuclear-cytoplasmic mRNA transport, mRNA stability, and mRNA translational efficiency. The poly(A) tail of mRNA is considered important for each of these processes, yet no clear understanding of poly (A) tail function exists. The long term objective of this work is to analyze the role(s) of poly(A) in mRNA metabolism and to understand how modifications in it or the protein bound to it, the poly(A)-binding protein, can affect this metabolism. With this understanding, potential alterations of poly(A)-dependent steps in mRNa metabolism resulting from cellular infection or transformation can be studied. The initial objective of the work is to characterize genes in Saccharomyces cerevisiae which affect poly(A) synthesis, packaging, and degradation. These include genes encoding a poly(A)-polymerase, the poly(A)-binding protein, and seven genes (spbl-spb7) which when mutated allow the cells to live without the essential poly(A)-binding protein. One of these, SPB2, encodes the ribosomal protein L46, and another, SPB4, encodes a protein which is highly homologous to eucaryotic initiation factor 4a and is probably an RNA-helicase. The effects of mutations in these genes on in vivo mRNA transport, poly(A) and mRNA stability, and mRNA translation will be examined. An in vitro poly(A)-degradation assay that faithfully reproduces the in vivo effects of these mutations will be developed. This assay will detect the functional interactions between the poly(A) tail and the remainder of the mRNA, and it will be a model system for studying messenger ribonucleoprotein structure and its affects on mRNA stability.