A cardiac-related, promoter-proximal, regulatory element shapes chromatin and JAG1 transcription

The Jagged1 ( JAG1 ) gene is essential for cardiac development, yet its tissue-specific transcriptional regulation remains poorly understood. In this study we used an integrative screening approach to identify 19 candidate enhancers within the ±100 kb region flanking the JAG1 locus, among which R7 exhibited the highest activity in dual-luciferase assays. CRISPR/Cas9-mediated deletion of R7 in AC16 cells significantly reduced JAG1 expression, decreased proliferative and migratory capacities, and increased apoptosis. Mechanistically, R7 deletion altered local chromatin contacts and reduced accessibility at CTCF-bound regions near the JAG1 promoter, accompanied by decreased H3K27ac, H3K4me3, RNA polymerase II, and SRF occupancy. These findings identify R7 as a cardiac-associated promoter-proximal regulatory element with enhancer-like activity that contributes to local chromatin organization and transcriptional activity at the JAG1 locus.