Language

English

Publication Date

11-28-2025

Journal

Science Advances

DOI

10.1126/sciadv.adt5937

PMID

41296873

PMCID

PMC12652325

PubMedCentral® Posted Date

11-26-2025

PubMedCentral® Full Text Version

Post-print

Abstract

Loss-of-function mutations in methyl-CpG binding protein 2 (MECP2) cause Rett syndrome. While we know that MeCP2 binds to methylated cytosines on DNA, the full breadth of the molecular mechanisms by which MeCP2 regulates gene expression remains incompletely understood. Here, using a genetic modifier screen, we identify the super elongation complex, a P-TEFb–containing elongation factor that releases promoter-proximally paused RNA polymerase II, as a genetic interactor of MECP2. MeCP2 physically interacts with SEC subunits and directly binds AFF4, the scaffold of the SEC, via the transcriptional repression domain. Furthermore, MeCP2 facilitates the binding of AFF4 on a subset of genes in the mouse brain regulating synaptic plasticity and concordantly promotes the binding of RNA polymerase II on these genes. Last, while haploinsufficiency of Aff4 does not exhibit any behavioral deficits in mice, it exacerbates the impaired contextual learning behavior of Mecp2 hypomorphic mice. We propose a previously unknown mechanism by which MePC2 regulates gene expression underlying synaptic plasticity.

Keywords

Methyl-CpG-Binding Protein 2, Animals, Mice, Transcription, Genetic, Protein Binding, Humans, Gene Expression Regulation, RNA Polymerase II, Neuronal Plasticity, Rett Syndrome, Brain

Published Open-Access

yes

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