线粒体上核糖核蛋白基因内含子与相应编码序列的相互作用分析

Interactions Between Introns and Corresponding Protein Coding Sequences of Mitochondrial Ribosomal Protein Genes

剪切后的内含子对基因的表达调控过程仍发挥着重要的作用,发现内含子通过与相应mRNA的相互作用来实现这些功能的.用改进后的Smith-Waterman算法进行局域比对,对线虫、果蝇、小鼠和人类的线粒体上核糖核蛋白基因的内含子与相应编码序列做匹配性比对分析,发现内含子的中部序列与编码序列存在较强的相互作用,三类内含子上的匹配频率分布显示了各自的特征.在编码序列上有多个最佳匹配区域和禁配区域,推测这些禁配区域可能是蛋白质复合体的结合区域.最佳匹配片段的GC含量分布范围较广,覆盖了其它三类序列分布范围.高等真核生物最佳匹配片段的平均长度比低等真核生物要长一些.结论表明最佳匹配片段的序列特征符合RNA-RNA相互作用的一般规律,内含子应该是一类调控基因表达的功能片段.

Post--spliced introns play a very important role in regulating gene expression; it is found that intron functions are carried out by the interactions between introns and the corresponding mRNAs. Based on the ribosomal protein genes of mitochondrial in C. elegans, D. melanogaster, M. musculus and H. sapiens, matching alignment analysis between introns and their corresponding pro- tein coding sequences were done by using the improved Smith--Waterman algorithm. Our results showed that the middle regions of introns have high matching frequencies. The matching frequency distributions of first introns,middle introns and last introns are different from each other and have their own characters. There are many optimal matched regions and forbidden regions distributed in protein coding sequences. It is speculated that the forbidden regions may be the binding regions of a protein complex. All GC content distribution ranges of the optimal matched segments are very wide and cover the GC content ranges of introns,exons and protein coding sequences. Average lengths of the optimal matched segments are longer for high eukaryotes than low eukaryotes. Our results showed that the sequence characters of the optimal matched segments correspond directly with the interaction characters of RNA--RNA and introns should be a kind of function segments in the process of gene regulate.