Kuersten Scott, Goodwin Elizabeth B
Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706, USA.
Biol Cell. 2005 Jun;97(6):469-78. doi: 10.1042/BC20040106.
From the very beginning, mRNAs have a complex existence. They are transcribed, capped, spliced, modified at the 3'end, exported from the nucleus, translated, and eventually degraded. These many events not only affect the overall survival and properties of an mRNA, but are also carefully co-ordinated and integrated with quality control mechanisms that function to ensure that only 'proper' mRNAs are translated at the correct developmental time and place. This does not mean that all mRNAs follow a single or uniform path from synthesis to death. Instead, there are diverse means by which the activities of specific mRNAs are regulated, and these controls often depend upon multiple events in the mRNA's life. mRNAs are not found naked in the cell, instead they are part of complex RNPs (ribonucleoproteins) that consist of many factors. These RNPs are highly dynamic structures that change during the lifetime of a given RNA; linking events such as synthesis and processing to the final fate of the mRNA. Here, we will discuss what is known of the assembly of RNPs in general, with specific reference to the myriad of connections between different nuclear events and the cytoplasmic activity of an mRNA. Due to space limitations this review is not comprehensive, instead we focus on specific examples to illustrate these emerging themes in gene expression.
从一开始，信使核糖核酸（mRNA）就有着复杂的存在形式。它们被转录、加帽、剪接、在3'端修饰、从细胞核输出、翻译，最终降解。这些众多事件不仅影响mRNA的整体存活和特性，还与质量控制机制仔细协调并整合，这些机制的作用是确保只有“合适的”mRNA在正确的发育时间和地点被翻译。这并不意味着所有mRNA都遵循从合成到降解的单一或统一路径。相反，特定mRNA的活性有多种调控方式，而且这些调控通常取决于mRNA生命周期中的多个事件。mRNA在细胞中并非单独存在，相反，它们是由许多因子组成的复杂核糖核蛋白（RNP）的一部分。这些核糖核蛋白是高度动态的结构，在给定RNA的生命周期中会发生变化；将诸如合成和加工等事件与mRNA的最终命运联系起来。在这里，我们将总体讨论核糖核蛋白的组装情况，特别提及不同核事件与mRNA细胞质活性之间的众多联系。由于篇幅限制，本综述并不全面，而是侧重于具体例子来说明基因表达中的这些新出现的主题。
