PXD065449

PXD065449 is an original dataset announced via ProteomeXchange.

Title	A H3K27me3 reader complex couples H3K27me3 accumulation to nascent transcription of transposable elements in Paramecium
Description	Background The ability to deposit histone H3K27-trimethyl (me3) marks is essential for transcriptional repression by Polycomb Repressive Complex 2 (PRC2). This is largely attributed to Polycomb repressive complex 1 (PRC1), whose recruitment is H3K27me3-dependent. Yet it is unclear how H3K27me3 contributes to transcription regulation independently of PRC1. Results To address this question, we identified H3K27me3-binding proteins in the unicellular eukaryote Paramecium where PRC2 targets transposable elements (TEs) and PRC1 is absent. We show that the chromodomain protein Firefly is a H3K27me3 reader in vitro and accumulates onto TEs in a H3K27me3-dependent manner. We also identify Firefly interactors: Sleepy, a coiled-coil containing protein and TfIIs4, a transcription elongation factor. We show that Firefly, Sleepy and TfIIs4 are jointly required in vivo for correct H3K27me3 accumulation and nascent transcription at TEs. Conclusions This positive feedback loop to enrich H3K27me3 at TEs is analogous to self-reinforcing loops leading to H3K9 methylation at repeats in fungi, plants and animals. Our work reveals a unique association between H3K27me3 readers and active transcription.
HostingRepository	PRIDE
AnnounceDate	2026-03-03
AnnouncementXML	Submission_2026-03-03_03:06:32.727.xml
DigitalObjectIdentifier
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Unsupported dataset by repository
PrimarySubmitter	Guillaume CHEVREUX
SpeciesList	scientific name: Paramecium tetraurelia; NCBI TaxID: NEWT:5888;
ModificationList	monohydroxylated residue; deamidated residue
Instrument	timsTOF Pro 2

Revision	Datetime	Status	ChangeLog Entry
0	2025-06-25 09:00:57	ID requested
⏵ 1	2026-03-03 03:06:33	announced

Dataset with its publication pending

submitter keyword: None

Sandra Duharcourt
contact affiliation	Université Paris Cité, CNRS, Institut Jacques Monod, 15 rue Hélène Brion, F-75013 Paris, France
contact email	sandra.duharcourt@ijm.fr
lab head
Guillaume CHEVREUX
contact affiliation	Institut Jacques Monod, CNRS UMR7592
contact email	guillaume.chevreux@ijm.fr
dataset submitter

Dataset FTP location NOTE: Most web browsers have now discontinued native support for FTP access within the browser window. But you can usually install another FTP app (we recommend FileZilla) and configure your browser to launch the external application when you click on this FTP link. Or otherwise, launch an app that supports FTP (like FileZilla) and use this address: ftp://ftp.pride.ebi.ac.uk/pride/data/archive/2026/03/PXD065449

PRIDE project URI

• PRIDE
  1. PXD065449
     1. Label: PRIDE project
     2. Name: A H3K27me3 reader complex couples H3K27me3 accumulation to nascent transcription of transposable elements in Paramecium