组蛋白修饰在四个基因集合中的分布特征

Distribution Feature of Histone Modifications in the Four Gene Sets

基于人类全基因组Feb.2009(GRCh37/hg19版本)的基因注释数据,筛选得到12207个在TSS前后20kb内无重叠的基因.以人类GM12878和K562两种细胞系为研究对象,通过计算基因与转录因子CTCF的关联强度得分Aij以及TSS附近的DNA甲基化水平Mij,将12207个基因分为四个集合,分别统计了每个基因集合中TSS侧翼3800bp区域内的11种组蛋白修饰信号的分布情况.结果显示H2AFZ、H3K4me2、H3K4me3、H3K9ac、H3K27ac和H3K79me2这六种呈现明显的双峰分布,且在GM_III和K_III集合中信号最强,在GM_II和K_II集合中信号最弱,表明CTCF的结合与DNA甲基化可以影响组蛋白修饰的分布.

Based on the hgl9 RefSeq gene annotations from the UCSC website browser, 12207 non-overlapping genes within 20kb upstream and downstream regions of transcription start sites （TSS） were extracted. For human GM12878 and K562 cell lines,the association strength named Aij between the transcription factor CTCF and each gene and DNA methylation level named Mij around transcription start sites were calculated. Next, 12207 genes were classified into four gene sets ac- cording to the values of A0 and M,〉 ,and the distribution of 11 HMs were analyzed within 3800bp in the flanking regions of transcription start sites in each set respectively. The results show that H2AFZ, H3K4me2, H3K4me3, H3K9ac, H3K27ae and H3K79me2 exhibit bimodal distributions, with the highest signal distributions in GM_III and K_III sets and the lowest in GM_II and K_II sets, which indicate that CTCF binding and DNA methylation have some effect on the distribution of histone modifications.