Sequence and chromatin determinants of cell-type-specific transcription factor binding

Area of Science:

• Genomics
• Molecular Biology
• Bioinformatics

Background:

• Gene regulation relies on cell-type-specific transcription factor (TF) binding.
• TF binding is influenced by DNA sequence, cofactors, and chromatin context.
• Understanding these determinants is key to deciphering cell-specific gene expression.

Purpose of the Study:

• To investigate the contributions of DNA sequence, histone modifications, and DNase accessibility to cell-type-specific TF binding.
• To develop advanced computational models for predicting TF occupancy.
• To identify factors where DNA sequence plays a critical role in cell-specific binding.

Main Methods:

• Analyzed 286 ChIP-seq experiments from the ENCODE Consortium.
• Utilized support vector machines (SVMs) with k-mer patterns for DNA sequence modeling.
• Employed SVMs to model spatial chromatin signatures (histone modifications, DNase accessibility).

Main Results:

• Advanced SVM models significantly improved TF occupancy predictions compared to simpler methods.
• While DNase accessibility explains some cell-specific binding, DNA sequence preferences are critical for others.
• Identified specific binding sites with cell-type-specific sequence preferences, even when accessible in both cell types.

Conclusions:

• Cell-type-specific DNA sequence preferences are a significant determinant of TF binding, alongside chromatin accessibility.
• Relying solely on chromatin accessibility or single TF motifs is insufficient for accurate prediction of cell-specific binding profiles.
• Advanced sequence and chromatin modeling is essential for understanding cell-type-specific gene regulation.