高等植物基因上游可译框架(uORF)的分析  

Upstream Open Reading Frames (uORF) Analysis of Plant mRNAs

作　　者：金勇丰[1] 边腾飞[1] 周萍[2] 

机构地区：[1]浙江大学生物化学研究所,杭州310029 [2]浙江省农业科学院蔬菜研究所,杭州310021

出　　处：《农业生物技术学报》2004年第5期493-499,共7页Journal of Agricultural Biotechnology

基　　金：留学回国基金项目(No.G50373)资助

摘　　要：真核生物 mRNA 5′非编码区上游可译框(uORF)在基因翻译水平上的调控具有重要作用。对植物2200多个 cD-NA 序列5′非编码区的 uATG 和 uORF 进行统计分析,结果表明,含 uATG 的基因高达18%,这一比例比估计的10%要高得多,其中含单个 uATG 的基因约占50%,含2个 uATG 的基因占20%左右;大部分 uORF 属于非交叉 uORF,约占85%;编码1～5氨基酸的 uORF 占30%以上,大部分 uORF 编码多肽小于20个氨基酸,占77.6%;mRNA ORF 起始密码子 ATG 的两边序列有显著的偏爱性,与植物共有序列 UAAACAAUGGCU 或 AACAAUGGC 基本一致,但有 uATG 的 mRNA ORF 起始密码子 ATG的两边序列比不含 uATG 的 mRNA ORF 起始密码子 ATG 的两边序列偏爱性要差。大多数 uATG 两边序列缺乏植物 ORF 起始密码子 ATG 的两边序列的偏爱性。不同种属 mRNA5′非编码区 uORF 氨基酸并不具有显著的同源性.如果植物 S-腺苷甲硫氨酸脱羧酶等少数基因具有非常保守的 uORF,氨基酸序列同源性高达75%～100%,显著高于植物 S-腺苷甲硫氨酸脱羧酶之间的同源性。The upstream open reading frames(uORF)in 5'-untranslated regions (5'-UTR)of eukaryotic mRNAs play an important role in translation efficiency.The computer analysis of upstream ATG and uORF of 5'-UTR of plants mRNA adopted from the nucleotide sequence databank revealed that up to 18% of 5'-UTRs contained uATG,much more than the previous estimate.A- mong them,about 50% of genes had one uATG and nearly 20% had two uATG.About 85% of uORFs were non-overlapping,and nearly 80% of them fell in the range of below 20 aa (30% of uORF peptides were 1～5 aa).Sequences flanking the uATG codon strik- ingly differed from the functional initiation codons and the upstream ATG triplets were more frequently located in a non-optimal con- text.Consensus sequences of the ATG codon contexts of mRNA with and without uATG were similar but the ATG codon contexts of mRNA without uATG were more frequently located in an optimal context than that of mRNA with uATG.Most of mRNA with uATG possibly had relation with the regulatory function.In addition,most of uORFs had no similiarity between plant mRNA species,where- as sequences of a few uORFs were highly conserved,such as uORFs of S-Adenosyl-L-methionine decarboxylase(AdoMet-DC)were 75%～100% homology between plant mRNA species,which were much more conserved than AdoMetDC.

关 键 词：基因 RNA 非编码区 序列 列缺 翻译水平 氨基酸 起始密码子 高等植物 真核生物 

分 类 号：S852[农业科学—基础兽医学] Q61[农业科学—兽医学]