秀丽线虫基因组中的回文序列分布

Palindrome distribution in the C. elegans genome

回文序列在基因组既可以作为基因表达调控的模体,也能引起基因组的不稳定而导致疾病.本文通过全基因组范围的回文识别,揭示回文在线虫基因组上的总体分布模式,并结合回文丰度和分布特征,探讨回文的生物学功能.结果发现:(1)基因组不同功能区域(如编码区、内含子、基因间区)中,回文在内含子中分布最多,基因间区次之,在编码区分布最少;(2)回文的相对丰度随着回文长度的增加而增加,这反映了基因组对不同长度回文的使用选择性;(3)总体而言回文GC含量随着回文长度的增加而降低,而且在不同的基因组区域(编码区、内含子和基因间区)中回文的GC含量有很大差异;(4)搜索转录因子结合位点模体与回文模体,发现转录因子结合位点富含模体与回文模体,且转录因子结合位点模体中有很明显的回文模体,表明回文可能作为转录因子结合模体而调控转录.

Genomic palindromes can not only act as gene regulatory motifs but also cause diseases by inducing genome instability. In the present study, palindromes in the Caenorhabditis elegans genome was identified, the overall distribution pattern of palindromes across the genome was uncovered, and then the possible functions of palindromes in light of the palindrome distribution and abundance in the ge- nome were discussed. Results show that： （ 1 ） Among the different kinds of genomic regions such as CDS, introns and intergenic se- quences, palindrome abundance decreases in the order of introns, intergenic sequences, and CDS ; （2） As the palindrome size increases, its relative abundance becomes larger, suggesting the distinct selection on the usage of different - sized palindromes in the genome ; （3） The GC content of palindromes tends to decrease with increasing palindrome size, and different genomic regions including CDS,inter- genic sequences, and introns show distinct palindrome GC content; （4） Palindromes are enriched in transcription factor binding sites, and there are obvious palindrome motif in motif of TFBS,suggesting the potential role of palindromes in gene transcription.