BioProject

NKX2-5 is a homeodomain transcription factor that plays a central role in the cardiac gene regulatory network, and is commonly mutated in human congenital heart disease. More...

NKX2-5 is a homeodomain transcription factor that plays a central role in the cardiac gene regulatory network, and is commonly mutated in human congenital heart disease. Here, we take a functional genomics approach to congenital heart disease mechanism. We used DamID to establish a robust set of target genes for both wild type NKX2-5 and a mutation lacking the homeodomain (NKX2-5delHD), the latter to model loss-of-function in gene regulatory network. NKX2-5delHD bound hundreds of targets including NKX2-5 wild type targets and a unique set of “off-targets”, and retained partial functionality. We showed that NKX2-5delHD could heterodimerize with NKX2-5 wild type and cofactors, including ubiquitous ETS family members ELK1 and ELK4, through a tyrosine-rich homophilic interaction domain (YRD). NKX2-5delHD off-targets, but not those of an NKX2-5 YRD mutant, were enriched in ETS motifs and were occupied by ELK1/ELK4 proteins, as determined by DamID. Our study reveals unexpected activities for NKX2-5 mutations on chromatin, guided by interactions with their normal cardiac and general cofactors, and suggest potential for a novel type of gain-of-function in congenital heart disease. The supplementary bed file contains all binding regions detected for the N/C-terminal fusions reported in the manuscript, in addition to probe locations, ready to upload directly into UCSC browser (mm9). Overall design: DamID-chip TF binding analysis. N and C-terminal Dam fusions to ELK1, ELK4 and SRF vs. Input (dam-only) in HL-1 atrial cardiomyocytes. N-terminal Dam fusions to NKX2-5, NKX2-5YRD^(Y-A) and NKX2-5ΔHD (homeodomain deletion) vs. Input (dam-only) in HL-1 atrial cardiomyocyte. Less...