IDENTIFICATION OF DNA FEATURES AT THE TRANSITION REGION OF VARIOUS CHROMATIN STATES

Abstract

Epigenetic factor plays an important role in regulation of gene expression and functions. ChIP-seq experiments (chromatin immune precipitation along with sequencing) are frequently used for mapping those epigenetic states throughout the genome. Histone modification is such an epigenetic factor which is analyzed using ChIP-seq experiment.Generally, data generated by these experiments are very noisy and diffused. Good signal values of ChIP-seq can range from few nucleotides to large domains. Histones are modified by post translational modifications such as methylation, acetylation, phosphorylation and ubiquitination, hence they influences the gene expression.One of modification H3K27me3(histone 3 lysine 27 trimethylation) is known for shutting down the transcription when it tightly associates with inactive gene promoters by trimethylation. H3K27me3 data are very difficult to analyze compared to other datasets as they do not have very distinct signal peaks. So by genome-level analysis of four different developmental stages of Drosophila melanogaster for H3k27me3 (ChIP-seq) data we are trying to identify the DNA signaturesthat are responsible for the initiation and ending of those modifications. Our objective is the comparative study of motif enrichment within the signal regions and transition regions to find the possible motif for those histone modifications. H3K4me3 acts in oppositionto H3K27me3 so it is used as a negative control.