期刊
NUCLEIC ACIDS RESEARCH
卷 32, 期 17, 页码 4969-4978出版社
OXFORD UNIV PRESS
DOI: 10.1093/nar/gkh823
关键词
-
Under no-strand bias conditions, each genomic DNA strand should present equimolarities of A and T and of G and C. Deviations from these rules are attributed to asymmetric properties intrinsic to DNA mutation-repair processes. In bacteria, strand biases are associated with replication or transcription. In eukaryotes, recent studies demonstrate that human genes present transcription-coupled biases that might reflect transcription-coupled repair processes. Here, we study strand asymmetries in intron sequences of evolutionarily distant eukaryotes, and show that two superimposed intron biases can be distinguished. (i) Biases that are maximum at intron extremities and decrease over large distances to zero values in internal regions, possibly reflecting interactions between pre-mRNA and splicing machinery; these extend over similar to0.5 kb in mammals and Arabidopsis thaliana, and over 1 kb in Caenorhabditis elegans and Drosophila melanogaster. (ii) Biases that are constant along introns, possibly associated with transcription. Strikingly, in C.elegans, these latter biases extend over intergenic regions that separate co-oriented genes. When appropriately examined, all genomes present transcription-coupled excess of T over A in the coding strand. On the opposite, GC skews are either positive (mammals, plants) or negative (invertebrates). These results suggest that transcription-coupled asymmetries result from mutation-repair mechanisms that differ between vertebrates and invertebrates.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据