A CRISPR-Activation CROP-seq Screen Identifies HMGN1 as a Dosage Sensitive Regulator of Heart Defects in Down Syndrome (scRNA-Seq)

Congenital heart defects (CHD) are the most common form of developmental abnormalities, occurring in ~1% of live births, and can arise due to altered dosage of genes essential for cardiogenesis. Aneuploidy accounts for nearly 15% of CHD and the most frequent form involves trisomy of chromosome 21 (Ch21), resulting in Down Syndrome (DS). Here we used single cell RNA-seq, CRISPR-activation with single cell RNA-seq, single cell ATAC-seq and Cut&Tag epigenomic profiling to define the molecular disruptions occuring with Trisomy 21 and upregulation of the Ch21 epigenetic factor HMGN1. These experiments were performed in human pluripotent stem cells (hiPSCs) or in directed differentiation to cardiomyocyte lineages at days 10 and 20.