biostudies-literatureUnknown17(1)Wan XDNA topology is critical for regulating transcription and maintaining cellular homeostasis. Z-DNA is a left-handed DNA helix in regions with high transcriptional activity. Its physiological function remains poorly understood. Here, we demonstrate that oncoprotein MYC induces the formation of Z-DNA by recruiting the chromatin remodeler FACT, independent of RNA Polymerase II activity. FACT facilitates Z-DNA formation by remodeling H2A/H2B dimers within intact nucleosomes. Additionally, the phosphorylation of FACT regulates its liquid-liquid phase separation, promoting its efficient recruitment to chromatin by MYC. Through a genome-wide analysis and characterization of engineered Z-DNA promoters, we found that Z-DNA directly facilitates the loading of RNA Polymerase II, thereby promoting tranNature communications199https://www.ebi.ac.uk/biostudies/studies/S-EPMC12780141biostudies-literatureMYC drives left-handed Z-DNA formation to shape gene expression.PMC12780141Liu YFan HLi ZShao JFang DZhang YDu YWan XZeng WSun ZJia JfalseMYC drives left-handed Z-DNA formation to shape gene expression.DNA topology is critical for regulating transcription and maintaining cellular homeostasis. Z-DNA is a left-handed DNA helix in regions with high transcriptional activity. Its physiological function remains poorly understood. Here, we demonstrate that oncoprotein MYC induces the formation of Z-DNA by recruiting the chromatin remodeler FACT, independent of RNA Polymerase II activity. FACT facilitates Z-DNA formation by remodeling H2A/H2B dimers within intact nucleosomes. Additionally, the phosphorylation of FACT regulates its liquid-liquid phase separation, promoting its efficient recruitment to chromatin by MYC. Through a genome-wide analysis and characterization of engineered Z-DNA promoters, we found that Z-DNA directly facilitates the loading of RNA Polymerase II, thereby promoting tran2025-01-01T00:00:00Z2025 Dec2026-06-06T12:42:21.937Z2026-05-30T03:11:38.679ZS-EPMC127801414132640710.1038/s41467-025-66886-3