Description
Formation of biomolecular condensates by phase separation has recently emerged as a new principle for regulating gene expression in response to extracellular signaling. However, the molecular mechanisms underlying the coupling of signal transduction and gene activation through condensate formation, and how dysregulation of these mechanisms contributes to disease progression, remain elusive. Here we report that CREB-regulated transcription coactivator 2 (CRTC2) translocates to the nucleus and forms phase-separated condensates upon activation of cAMP signaling. We show that intranuclear CRTC2 interacts with positive transcription elongation factor b (P-TEFb) and activates P-TEFb by disrupting the inhibitory 7SK snRNP complex. Aberrantly elevated cAMP signaling plays central roles in the development of autosomal dominant polycystic kidney disease (ADPKD). We find that CRTC2 localizes to the nucleus and forms condensates in cystic epithelial cells of both mouse and human ADPKD kidneys. Genetic depletion of CRTC2 suppresses cyst growth in an orthologous ADPKD mouse model. Using integrative transcriptomic and cistromic analyses, we identify CRTC2-regulated cystogenesis-associated genes, whose activation depends on CRTC2 condensate-facilitated P-TEFb recruitment and the release of paused RNA polymerase II. Together, our findings elucidate a mechanism by which CRTC2 nuclear condensation conveys cAMP signaling to transcription elongation activation and thereby promotes cystogenesis in ADPKD.
Overall Design
For ChIP-seq. Cells were cross-linked with 1% formaldehyde in 1 mL PBS for 10 min at RT. The crosslink was quenched by adding 67 L of 2.5 M glycine(150 mM final). Cells were washed with PBS and harvested using ChIP lysis buffer. Cells were then sonicated to obtain fragments (200-500 bp) with Sonicator. Immunoprecipitation was performed with indicated antibodies. After elution and reversal cross-linking, DNA was purified for library preparation.
Curator
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