Global dynamics of stage-specific transcription factor binding during thymocyte development

Area of Science:

• Immunology
• Developmental Biology
• Genomics

Background:

• Transcription factors (TFs) regulate gene expression during vertebrate development by binding to regulatory elements.
• Identifying TF binding sites is crucial for understanding gene regulation, but traditional methods like ChIP are limited by antibody availability.
• Analyzing TF binding at multiple genes and developmental stages is challenging.

Purpose of the Study:

• To assess if ATAC-seq can predict TF binding to enhancers in thymocytes.
• To infer the identity of TFs binding to Cd4, Cd8, and Gata3 regulatory elements.
• To generate stage-specific T cell open chromatin profiles and identify TFs driving thymocyte differentiation.

Main Methods:

• Performed ATAC-seq at four developmental stages in mouse thymus: double negative (DN), double positive (DP), CD4 single positive (SP4), and CD8 SP (SP8).
• Integrated chromatin accessibility data with TF motif information genome-wide.
• Inferred stage-specific TF binding sites within known and novel regulatory elements.

Main Results:

• Generated genome-wide, stage-specific open chromatin profiles for T cells.
• Successfully inferred TF binding site occupancy within regulatory elements.
• Identified candidate TFs responsible for driving thymocyte differentiation at distinct developmental stages.

Conclusions:

• ATAC-seq is a viable method for inferring TF binding without specific antibodies.
• This approach provides valuable insights into the regulatory networks governing T cell development.
• The identified TFs offer potential targets for understanding and manipulating thymocyte differentiation.