The Study On Histone Modifications And Gene Expression In Four Cells Of Human And Mouse

Histone modification is one of epigenetic modifications,it has relationship with inflammation reaction?gene expression and disease occurrence.Human and mouse are similar in cell structure and anatomic form.In this paper,the difference of histone modifications between human and mouse is studied.The 7 histone modifications data,Refseq data and RNA-seq data in embryonic stem cell with differential function H1-hesc(human),ES-bruce4(mouse),and in undifferentiated leukemia cell K562(human)?MEL(mouse)etc four cell lines are analyzed.In homologous gene,we compute and compare the distribution of histone modification in genome wide and flanking transcriptional start site(TSS)for the four cell lines,the fold change of histone modification and the spearman correlation between histone modifications in high expression and low expression genes;The pearson correlation between histone modification and gene expression(RPKM)are calculated in difference gene set.The GO and KEGG analyses for genes with not co-own are made;and the pearson correlations of histone modifications and gene expressions are calculated in cancer pathway.The distributions of histone modification in oncogene and TSG of chronic myelogenous leukemia(CML)pathway are compared,the distribution of histone modifications in single gene are calculated by IGV software.The main research results of this article are as follows:1.We analyze the fold change of H3K4me3 in the high expression genes compared with low expression genes,find the fold change of H3K4me3 in human and mouse cancer cell is higher than normal cell.We analyze correlation between histone modifications in the high expression genes and low expression genes,found that correlation in human H1-hesc and K562 are similar,and mouse ES-bruce4 and MEL are similar in high expression genes.2.By computing the correlation between histone modification and RPKM around TSS 2000 bp in three gene sets,we found H3K27me3 is both negative correlation in the homologous gene of human and mouse.Human have negative correlation and mouse have all positive correlation in NR gene set.The genes set with not co-own may be the reason that the two parts correlation result is difference.3.The KEGG analysis for the genes set with not co-own shows that their mainly difference is olfactory pathway in human and mouse genes.Using IGV software to analyzes histone modification signals,we find that the signal distributions of histone modifications H3K27 ac for gene Cdkn2 a in mouse and gene CDKN2 A in human is difference in normal cell and cancer cell.