The homeobox transcription factors NKX2-5 and MEIS1 are essential for vertebrate heart development and normal physiology of the adult heart. We show that, during cardiac differentiation, the two transcription factors have partially overlapping expression patterns, with the result that as cardiac progenitors from the anterior heart field differentiate and migrate into the cardiac outflow tract, they sequentially experience high levels of MEIS1 and then increasing levels of NKX2-5. Using the Popdc ...[more]
Project description:We report the transcriptome analysis of E11.5 mouse embryonic heart presenting a reduction in Nkx2-5 expression compare to wild-type littermate. Transcriptome analysis of 3 different E11.5 hypomorphic hearts against 3 controls littermate hearts.
Project description: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.