Rottman F M, Bokar J A, Narayan P, Shambaugh M E, Ludwiczak R
Department of Molecular Biology and Microbiology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106, USA.
Biochimie. 1994;76(12):1109-14. doi: 10.1016/0300-9084(94)90038-8.
The N6-methylation of internal adenosine residues is a common post-transcriptional modification of eukaryotic pre-mRNA sequences. An in vitro methylation system which retains the precise selectivity of in vivo methylation sites has been used to further define the nature of RNA site recognition. In addition to short consensus sequences, other structural features or context effects contribute to the selection of methylation sites in pre-mRNAs. Partial purification of the mRNA N6-adenosine methyltransferase revealed unexpected levels of complexity. The methyltransferase is composed of three separate components with molecular masses of 30, 200 and 875 kDa, respectively. These components are readily separated under non-denaturing conditions and each is required for mRNA methylation activity.
内部腺苷残基的N6-甲基化是真核生物前体mRNA序列常见的转录后修饰。一种保留体内甲基化位点精确选择性的体外甲基化系统已被用于进一步确定RNA位点识别的性质。除了短的共有序列外，其他结构特征或上下文效应也有助于前体mRNA中甲基化位点的选择。mRNA N6-腺苷甲基转移酶的部分纯化揭示了意想不到的复杂程度。甲基转移酶由三个分别具有30、200和875 kDa分子量的独立组分组成。这些组分在非变性条件下很容易分离，并且每个组分都是mRNA甲基化活性所必需的。
