Architectural role of cell-fate-instructive transcription factor MyoD in orchestrating 3D genome organization in muscle cells.

Cell-type specific transcription factors play important roles in lineage specification whereas it is largely unknown whether and how they regulate context-specific 3D chromatin structure. Herein, we comprehensively mapped 3D chromatin organization in muscle cells and uncovered master transcription factor MyoD-mediated myogenic lineage specific chromatin structures in comparison with embryonic stem cells and neuronal cells. We discovered that MyoD is significantly enriched at loop anchor and mediate numerous chromatin loops without CTCF binding. Importantly, we found MyoD-involved interactions were dramatically disrupted when MyoD was absent, implying MyoD is an indispensable factor for loop regulation. Additionally, MyoD mediated shorter, weaker and more dynamic interactions, especially enhancer - enhancer and enhancer - promoter loops. Finally, MyoD mainly regulate cell type-specific contacts which were concomitant to muscle cell specific gene expression. Collectively, we utilized high resolution Hi-C data and genetic model to prove a master transcriptional factor govern lineage specific chromatin loops. We propose that MyoD-mediated interactions are a general feature of lineage specific transcriptional factors-regulated gene expression. Hi-C, ChIP-seq and RNA-seq of wildtype and MyoD-KO mouse during skeletal muscle differentiation Raw sequence data access provided at: China Genomic Sequence Archive (GSA) (under accession CRA002490,https://bigd.big.ac.cn/gsa/browse/CRA002490).