哺乳动物基因非翻译区开放阅读框架的分析

在所分析的5'UTR序列中约19%的序列在阅读框1下含有AUG,约22%和24%的序列分别在阅读框 2 和阅读框3下含有 AUG,而在 3'UTR序列当中,无论是在哪个阅读框下,约71%含有AUG.这些AUG绝大多数都是以小ORF的形式出现的;分析小ORF序列以及与它们相应的IC序列(阅读框间序列)长度,发现虽然3'UTR序列远远长于5'UTR序列,但是它们所包含的小ORF长度几乎没有差距,只是平均来说每一条3'UTR序列所包含的小ORF数量明显多于每一条5'UTR序列所包含的小ORF数量,而且dIC(下游阅读框间序列)比uIC(上游阅读框间序列)长很多,平均长50个碱基;第二类IC序列(UTR区相邻的两个阅读框之间的序列)的平均长度比其它两类IC序列(UTR区最后一个阅读框之后的序列)的平均长度小,而且又含有相对较多的终止密码;比较uORF序列与dORF序列密码子使用偏好的CAI值发现,尽管相差不大,但是无论在哪个阅读框下,uORF序列的CAI值都显著高于dORF序列的CAI值.

Analysis of Open Reading Frames on Untranslated Regions of Mammal Genes

Nearly 19% of 5'UTRs have AUG in reading frame 1, and nearly 22% and 24% of 5'UTRs have AUG in reading frame 2 and 3 respectively. However,for 3'UTR,71% of them have AUG. Most AUGs appear as small ORFs; Analysis of the length of small ORFs and its corresponding intersictronic sequences appears that 3'UTR is far longer than 5'UTR,but there are almost no difference between the length of small ORFs. However,the average number of small ORF contained in per 3'UTR is obviously more than the average number of small ORF contained in per 5'UTR,and dIC (downstream intersictronic sequences) is longer than uIC (upstream intersictronic sequences);The second type of IC sequences (sequences between open reading frames in UTR) is shorter than another two types of IC sequences (a segment of UTR sequence behind the last open reading frame),and there are relatively more stop codons in the second type of IC sequence;CAI value of uORF is significantly larger than CAI value of dORF.