Revis Biol Celular. 1988;18:1-112.
The relevance of the DNA molecule resides in that it carries all the genetic information within the cell. A molecule that directs and controls the expression of its encoded information through the interaction with other cellular components, is obviously compelled to display a full complement of salient features. First, the direct involvement of DNA in rather elaborate biological processes requires of the molecule to be structurally dynamic. Second, it appears that most eukaryotic genes are discontinuous. Their encoded information is interrupted by noncoding sequences which are transcribed along with the coding regions into full precursor RNA molecules. Since mature messenger RNA molecules are known to be substantially smaller that their corresponding primary nuclear transcripts, besides exhibiting chemical modifications, the latter must be subjected to coordinate processing steps to become fully functional in the cell. Indeed, mRNA molecules are derived from nuclear precursors through a variety of posttranscriptional chemical reactions involving end-terminal additions, excision of nonsense regions and orderly ligation of the coding sequences. The aim of this review is to emphasize the biological relevance of the conformational versatility of DNA and to address and discuss recent progress in messenger RNA processing in eukaryotes.
DNA分子的重要性在于它携带了细胞内所有的遗传信息。一个通过与其他细胞成分相互作用来指导和控制其编码信息表达的分子，显然必须展现出一整套显著特征。首先，DNA直接参与相当复杂的生物过程，这就要求该分子在结构上具有动态性。其次，大多数真核基因似乎是不连续的。它们的编码信息被非编码序列打断，这些非编码序列与编码区域一起转录成完整的前体RNA分子。由于已知成熟的信使RNA分子比其相应的初级核转录本小得多，除了表现出化学修饰外，后者还必须经过协同的加工步骤才能在细胞中完全发挥功能。实际上，mRNA分子是通过各种转录后化学反应从核前体衍生而来的，这些反应包括末端添加、无义区域的切除以及编码序列的有序连接。这篇综述的目的是强调DNA构象多样性的生物学重要性，并探讨和讨论真核生物中信使RNA加工的最新进展。
