RNA was isolated from hiPSC-CMs 48 hours after treatment with either scramble control or LMNA siRNA (+mChery control) using TRIzol reagent, following manufacturer's protocol (15596018, Invitrogen). CUT&RUN was performed using ~150,000 hiPSC-CMs and LMNB1 antibody or control IgG antibody as described in Skene & Henikoff 2018. RNA libraries were prepared using the NEBNext Ultra II DNA Library Prep kit (NEB) with the NEBNext Poly(A) mRNA Magnetic Isolation Module (NEB) to enrich for poly-A tailed RNA molecules. RNA-seq library quality was analyzed by TapeStation (Agilent Genomics) and quantified using qPCR (Kapa Biosystems). CUT&RUN DNA concentrations were quantified by Qubit (ThermoFisher) before library preparation using the NEBNext Ultra II DNA library prep kit (NEB). Samples were indexed for multiplex sequencing. Library quality was analyzed by TapeStation (Agilent Genomics) and quantified using qPCR (Kapa Biosystems).