R-loops shape the H2A.Z landscape and promote balanced lineage allocation during differentiation

Here, we use inducible Rnaseh1 expression in mouse embryonic stem cells (mESCs) to achieve acute, global R-loop depletion and systematically interrogate their impact on chromatin structure and lineage specification.

We find that R-loop loss has minimal effect on steady-state gene expression or self-renewal. Instead, it leads to a striking reduction in H2A.Z occupancy at both active and bivalent promoters, accompanied by increased nucleosome density—revealing a previously unrecognized role for R-loops in maintaining promoter architecture. During gastruloid differentiation, R-loop-depleted mESCs exhibit accelerated ectodermal differentiation, along with dysregulation of lineage-specific transcription factors and impaired cell-cell signaling.