REGULATION OF MRNA STABILITY IN MAMMALIAN CELLS

这项工作的目标是了解mRNA的衰变率是如何 在哺乳动物细胞中的调节以及mRNA半衰期的变化如何影响 细胞对生长和分化因子的反应， 致癌物质和环境压力。 在过去的五年里， mRNA稳定性的兴趣大大增加， 细胞质mRNA半衰期和基因表达之间的联系的认识 表情 细胞质衰变速率调节特别 重要的是mRNA的水平波动迅速响应各种 刺激。 这项建议的重点是两个mRNA的调控，组蛋白 和c-myc，以及感染细胞中宿主mRNA的不稳定性 单纯疱疹病毒1型（HSV-1）。 体外试验加基因 转染实验将用于鉴定 降解组蛋白和c-myc mRNAs，并表征调控 影响其衰变率的因素。 从这两个具体案例来看， 我们希望就其半衰期得出一些一般性结论 其他mRNA也受到调控。 HSV-1编码的蛋白质可诱导 显然，感染细胞中几乎所有宿主mRNA的不稳定性 通过激活宿主编码的有效mRNase活性。 我们希望 表征mRNase并确定其作用机制 诱导。 然后我们可以确定那些抑制mRNase的因素， 未感染的细胞，并确定mRNase的功能。

The goal of this work is to understand how the decay rates of mRNAs are regulated in mammalian cells and how changes in mRNA half-life influence the cellular responses to growth and differentiation factors, carcinogens, and environmental stress. During the past five years, interest in mRNA stability has increased substantially, with the recognition of the links between cytoplasmic mRNA half-life and gene expression. the regulation of cytoplasmic decay rates is particularly important for mRNAs whose levels fluctuate rapidly in response to various stimuli. This proposal focuses on the regulation of two mRNAs, histone and c-myc, and on the destabilization of host mRNAs in cells infected with herpes simplex virus type 1 (HSV-1). In vitro assays plus gene transfection experiments will be used to identify the enzymes that degrade histone and c-myc mRNAs and to characterize the regulatory factors that influence their decay rates. From these two specific cases, we hope to draw some general conclusions about how the half-lives of other mRNAs are regulated. An HSV-1-encoded protein induces the destabilization of almost every host mRNA in infected cells, apparently by activating a potent mRNase activity encoded by the host. We hope to characterize the mRNase and to determine the mechanism by which it is induced. Then we can identify those factors that repress the mRNase in uninfected cells and determine the function of the mRNase.