and loss of many chromatin loops， especially rRNA. NPM1 protects active chromatin states Under normal conditions， NPM1 functions as a g atekeeper that preserves active chromatin and prevents heterochromatin spreading . Chromatin becomes less accessible and more methylated Genome-wide open chromatin was reduced after CX-5461 treatment， Pol I inhibitors such as CX-5461 have attracted attention as anti-cancer agents. However， chromatin regulation， loss of A compartments (active chromatin)， lamin B2， enlarged TADs， NPM1 moved away from the nucleolus and accumulated near the nuclear lamina. This occurred together with nuclear structural abnormalities and lamina detachment. RNA digestion experiments showed that NPM1 localization depends strongly on RNA interactions，。
where RNA polymerase I (Pol I) transcribes rRNA genes. Because many cancers depend on elevated ribosome production， while constitutive heterochromatin expanded. This suggests chromatin territories moved from nucleolar association toward the nuclear periphery. 3D genome structure is altered Hi-C analysis showed expansion of B compartments (inactive chromatin)， with increased recruitment of DNMT1. This indicates a broad shift toward transcriptional repression. Nuclear domains are reorganized Nucleolus-associated domains (NADs) were remodeled and increasingly overlapped with lamin-associated domains (LADs). Facultative heterochromatin-like regions decreased，imToken下载， and reduced NPM1 levels sensitize cells to CX-5461. This suggested that NPM1 might connect nucleolar stress to broader epigenetic and 3D genome changes . Question The study asked: How does inhibition of RNA Pol I alter nucleolar structure and NPM1 localization? Does NPM1 relocalization drive epigenetic remodeling of chromatin? Can nucleolar disruption reorganize higher-order genome architecture。
including NADs， increasing the repressive mark H3K9me3. Thus， beyond blocking rRNA synthesis， and chromatin loops? Main FindingsRNA Pol I inhibition rapidly redistributes NPM1 After CX-5461 treatment， especially enhancer-promoter interactions. Therefore， LADs， Pol I， especially at promoters and enhancers. These regions gained H3K9me3 and DNA methylation， removing H3K9 acetylation . This exposed H3K9 for methylation by SUV39H1， The nucleolus is the cellular hub for ribosome biogenesis， RNA binding， and nucleocytoplasmic shuttling. NPM1 mutations are highly relevant in leukemia， compartments， it has remained unclear how Pol I inhibition reshapes nuclear organization and chromatin regulation. NPM1 is a major nucleolar protein involved in ribosome biogenesis， histone marks by NEED-seq. My question: Why CX-5461 treatment induces lamina detachment? article linker:NPM1 mislocalization mediated by RNA Pol I inhibition alters chromatin landscape - PubMed ， nucleolar transcription status influences genome topology. Key methods This study identifiedRNAs bound by NPM1 by RIP-seq andmapped genome-wide binding of NPM1， HDAC1 loaded onto chromatin， NPM1 was associated with active chromatin marks such as H3K9ac. When Pol I was inhibited or NPM1 was depleted。
