Language

English

Publication Date

9-5-2024

Journal

Molecular Cell

DOI

10.1016/j.molcel.2024.07.032

PMID

39173639

PMCID

PMC11380577

PubMedCentral® Posted Date

9-5-2025

PubMedCentral® Full Text Version

Author MSS

Abstract

Topoisomerase I (TOP1) is an essential enzyme that relaxes DNA to prevent and dissipate torsional stress during transcription. However, the mechanisms underlying the regulation of TOP1 activity remain elusive. Using enhanced cross-linking and immunoprecipitation (eCLIP) and ultraviolet-cross-linked RNA immunoprecipitation followed by total RNA sequencing (UV-RIP-seq) in human colon cancer cells along with RNA electrophoretic mobility shift assays (EMSAs), biolayer interferometry (BLI), and in vitro RNA-binding assays, we identify TOP1 as an RNA-binding protein (RBP). We show that TOP1 directly binds RNA in vitro and in cells and that most RNAs bound by TOP1 are mRNAs. Using a TOP1 RNA-binding mutant and topoisomerase cleavage complex sequencing (TOP1cc-seq) to map TOP1 catalytic activity, we reveal that RNA opposes TOP1 activity as RNA polymerase II (RNAPII) commences transcription of active genes. We further demonstrate the inhibitory role of RNA in regulating TOP1 activity by employing DNA supercoiling assays and magnetic tweezers. These findings provide insight into the coordinated actions of RNA and TOP1 in regulating DNA topological stress intrinsic to RNAPII-dependent transcription.

Keywords

DNA Topoisomerases, Type I, Humans, RNA-Binding Proteins, RNA Polymerase II, Protein Binding, DNA, Transcription, Genetic, RNA, Messenger, RNA, Cell Line, Tumor, DNA, Superhelical, HCT116 Cells, Nucleic Acid Conformation, TOP1, RNA binding protein, DNA supercoiling, magnetic tweezers, TOP1 interactome, transcription, topology

Published Open-Access

yes

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Graphical Abstract

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