Quantification of absolute transcription factor binding affinities in the native chromatin context using BANC-seq

Area of Science:

• Genomics
• Molecular Biology
• Epigenetics

Background:

• Transcription factor (TF) binding is crucial for gene regulation.
• Genome-wide TF binding is influenced by DNA sequence and chromatin structure.
• Quantifying the impact of chromatin on TF binding affinity remains challenging.

Purpose of the Study:

• To introduce a novel method, binding affinities to native chromatin by sequencing (BANC-seq), for measuring absolute apparent TF binding affinities.
• To enable quantitative analysis of TF interactions within their native chromatin environment.
• To explore the role of DNA sequence motifs versus chromatin context in TF binding.

Main Methods:

• BANC-seq involves incubating isolated nuclei with a range of concentrations of a tagged transcription factor.
• Concentration-dependent TF binding is measured across the genome using sequencing.
• This allows for the calculation of absolute apparent binding affinities for TFs to native DNA.

Main Results:

• BANC-seq successfully quantifies TF binding affinities across the genome in a native chromatin context.
• The method allows for stratification of genomic targets based on TF concentration.
• Results indicate that while consensus DNA binding motifs are important, they are not always essential for high-affinity TF binding.

Conclusions:

• BANC-seq provides a powerful quantitative tool for studying TF-DNA interactions.
• This method advances our understanding of how chromatin context modulates TF binding.
• BANC-seq facilitates predictions of TF binding under various physiological and non-physiological conditions, including disease states.