线虫核糖核蛋白基因外显子连接序列与其内含子的相互作用

Interactions between Exon-Exon Sequence and Its Corresponding Intron in Ribonucleoprotein Genes of C.elegans

剪接后的内含子与相应mRNA序列之间存在序列匹配关系,它们参与基因的表达和调控过程。为了揭示两者之间的序列匹配特征,对线虫核糖核蛋白基因的外显子连接序列与相应内含子序列采用Smith-Waterman局域比方法得到它们的最佳匹配片段,分析了外显子连接序列上的匹配频率F值分布。发现:1)连接点两侧匹配频率分布有明显的差异,显示出了外显子的边界。2)第一内含子和长内含子在外显子连接序列上的分布偏好与其他内含子有明显区别。3)对第一内含子而言,高GC含量的最佳匹配片段在外显子连接序列上表现出明显的偏置,在外显子上游EJC结合区域的匹配频率出现极小值分布。结果表明:EJC和内含子在与外显子序列结合的过程中存在相互竞争和相互协作的关系,内含子序列与编码序列是协同进化的,通过相互作用完成应有的功能。

Spliced introns have a matching relationship with the corresponding mRNA while they involve in the progress of gene expression and regulation.In order to reveal the sequence matching characteristics between them,based on ribonucleoprotein gene sequences of C.elegans,we use local matching method of Smith-Waterman to acquire the optimal matching segments between exon-exon sequences and the corresponding introns and analyze the distribution of matching frequency F values on exon-exon sequences.We find that,1)it gives exons’boundary that the matching frequency distribution has a distinct difference on two sides of the joint,2)the first introns and long introns have a different bias of distribution on exon-exon from other introns,3)for the first introns,the optimal matching segments with high G+C content display an obvious bias on exon-exon while there is a minimum of matching frequency on EJC binding region of upstream exons.Results show that,there are competition and cooperation between EJC and introns in the progress of their binding with exons,while through co-evolution introns with coding sequences can develop their own function.