ChIPpeakAnno

ChIPpeakAnno annotates peaks from chromatin immunoprecipitation sequencing (ChIP-seq) and chromatin immunoprecipitation microarray (ChIP-chip) data to map DNA–protein interactions and histone modifications and support functional interpretation.

Key Features:

• Sequence Retrieval: Extracts sequences surrounding identified peaks for downstream analysis.
• Gene Ontology (GO) Enrichment Analysis: Performs GO enrichment analysis for genomic regions to aid functional annotation.
• Proximity Analysis: Finds nearest genes, exons, microRNAs, or user-defined features such as conserved elements and transcription factor (TF) binding sites.
• Bi-directional Promoter Identification: Identifies peaks associated with bi-directional promoters.
• Motif Occurrence Summarization: Summarizes motif occurrences within identified peaks.
• Annotation Enhancement: Adds additional identifiers to annotated peaks or enriched GO terms.

Scientific Applications:

• Transcription Factor Binding Site Annotation: Annotates transcription factor binding sites from ChIP-seq and ChIP-chip datasets.
• Integration with Gene Expression: Integrates annotated peaks with gene expression data to distinguish direct and indirect transcription factor targets.
• Regulatory Network Analysis: Supports elucidation of transcriptional regulatory networks and their components.
• Public Data Integration: Facilitates analysis leveraging public datasets such as GEO (Gene Expression Omnibus).

Methodology:

Associates peaks with nearby genomic features and enriched GO terms for peak annotation, and integrates annotated peaks with gene expression data to distinguish direct versus indirect targets.