Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Panoramix SUMOylation at chromatin recruits the heterochromatin machinery to piRNA target loci [CUT&RUN]

ABSTRACT: Nuclear Argonaute proteins, guided by small RNAs, mediate sequence-specific heterochromatin formation. The molecular principles that link Argonaute–small RNA complexes, once bound to a nascent target RNA, to general heterochromatin effectors are poorly understood. Here, we uncover the mechanistic basis of how the PIWI interacting RNA (piRNA) pathway engages the heterochromatin machinery in Drosophila. Piwi-mediated recruitment of the corepressor complex SFiNX to chromatin leads to SUMOylation of its Panoramix subunit. SUMOylation, together with a hydrophobic LxxLL motif in the intrinsically disordered repressor domain of Panoramix, are necessary and sufficient to recruit Small ovary (Sov), a multi-zinc finger protein essential for general heterochromatin formation and viability. Structure-guided mutations that abrogate the Panoramix-Sov interaction or that prevent Panoramix SUMOylation uncouple Sov from the piRNA pathway, resulting in viable but sterile flies that exhibit de-repression of Piwi-targeted transposons. Thus, coupling the piRNA-guided recruitment of a corepressor to chromatin with its SUMOylation underlies sequence-specific heterochromatin formation.

ORGANISM(S): Drosophila melanogaster

PROVIDER: GSE173235 | GEO | 2021/08/22

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Panoramix SUMOylation at chromatin recruits the heterochromatin machinery to piRNA target loci [GRO-seq]

Project description:Nuclear Argonaute proteins, guided by small RNAs, mediate sequence-specific heterochromatin formation. The molecular principles that link Argonaute–small RNA complexes, once bound to a nascent target RNA, to general heterochromatin effectors are poorly understood. Here, we uncover the mechanistic basis of how the PIWI interacting RNA (piRNA) pathway engages the heterochromatin machinery in Drosophila. Piwi-mediated recruitment of the corepressor complex SFiNX to chromatin leads to SUMOylation of its Panoramix subunit. SUMOylation, together with a hydrophobic LxxLL motif in the intrinsically disordered repressor domain of Panoramix, are necessary and sufficient to recruit Small ovary (Sov), a multi-zinc finger protein essential for general heterochromatin formation and viability. Structure-guided mutations that abrogate the Panoramix-Sov interaction or that prevent Panoramix SUMOylation uncouple Sov from the piRNA pathway, resulting in viable but sterile flies that exhibit de-repression of Piwi-targeted transposons. Thus, coupling the piRNA-guided recruitment of a corepressor to chromatin with its SUMOylation underlies sequence-specific heterochromatin formation.

2021-08-22 | GSE173236 | GEO

Panoramix SUMOylation at chromatin recruits the heterochromatin machinery to piRNA target loci [ChIP-seq]

2021-08-22 | GSE173226 | GEO

Panoramix SUMOylation at chromatin recruits the heterochromatin machinery to piRNA target loci [RNA-seq]

2021-08-22 | GSE173222 | GEO

A nuclear RNA export factor variant licenses piRNA-guided heterochromatin formation

Project description:Small RNA silencing pathways protect genome integrity in part through establishing heterochromatin at transposon loci. In animals, this process requires piRNA-guided targeting of nuclear PIWI proteins to nascent transcripts. The molecular events contributing to heterochromatin formation upon PIWI binding to nascent RNA, a transient molecule at chromatin, are unknown. Here, we identify SFINX, a protein complex that is required for Piwi-mediated co-transcriptional silencing in Drosophila. It consists of Nxf2—a variant of the nuclear RNA export factor Nxf1/Tap, the mRNA export co-factor Nxt1/p15, and the Piwi-associated protein Panoramix. In the absence of Nxf2, Panoramix is targeted for degradation and piRNA-loaded Piwi is unable to establish heterochromatin. Consequently, nxf2 mutants exhibit severe transposon de-repression and are sterile. We show that within SFINX, Panoramix connects to the heterochromatin machinery while Nxf2 enables target silencing via nascent RNA. Thus, the Nxf2-Nxt1 heterodimer—despite having originated from core mRNA export machinery—has been repurposed for heterochromatin formation. Our data establish an unexpected link between nuclear small RNA biology and NXF-variants, which are widespread in animal lineages, but mostly lack ascribed functions.

2019-06-12 | PXD011201 | Pride

The nascent RNA binding complex SFiNX licenses piRNA-guided heterochromatin formation

Project description:The PIWI-interacting RNA (piRNA) pathway protects animal genome integrity in part through establishing repressive heterochromatin at transposon loci. Silencing requires piRNA- guided targeting of nuclear PIWI proteins to nascent transposon transcripts, yet the subsequent molecular events are not understood. Here, we identify SFiNX (Silencing Factor interacting Nuclear eXport variant), an interdependent protein complex required for Piwi-mediated co-transcriptional silencing in Drosophila. SFiNX consists of Nxf2-Nxt1, a gonad- specific variant of the heterodimeric mRNA export receptor Nxf1-Nxt1, and the Piwi-associated protein Panoramix. SFiNX mutant flies are sterile and exhibit transposon de-repression because piRNA-loaded Piwi is unable to establish heterochromatin. Within SFiNX, Panoramix recruits the cellular heterochromatin machinery, while Nxf2 binds the nascent target RNA and licenses co-transcriptional silencing. Our results reveal an unexpected, RNA-export independent role for Nxf2 in nuclear small RNA biology and suggest that NXF-variants, which have largely unknown function in animals, are functionally linked to the genome-transposon conflict.

2019-04-17 | GSE120617 | GEO

Dimerisation of the PICTS complex via LC8/Cut-up drives co-transcriptional transposon silencing in Drosophila

Project description:In animal gonads, the PIWI-interacting RNA (piRNA) pathway guards genome integrity in part through the co-transcriptional gene silencing of transposon insertions. In Drosophila ovaries, piRNA-loaded Piwi detects nascent transposon transcripts and instructs heterochromatin formation through the Panoramix-induced co-transcriptional silencing (PICTS) complex, containing Panoramix, Nxf2 and Nxt1. Here, we report that the highly conserved dynein light chain LC8/Cut-up (Ctp) is an essential component of the PICTS complex. Loss of Ctp results in transposon de-repression and a reduction in repressive chromatin marks specifically at transposon loci. In turn, Ctp can enforce transcriptional silencing when artificially recruited to RNA and DNA reporters. We show that Ctp drives dimerisation of the PICTS complex through its interaction with conserved motifs within Panoramix. Artificial dimerisation of Panoramix bypasses the necessity for its interaction with Ctp, demonstrating that conscription of a protein from a ubiquitous cellular machinery has fulfilled a fundamental requirement for a transposon silencing complex.

2021-01-26 | PXD022105 | Pride

Dimerisation of the PICTS complex via LC8/Cut-up drives co-transcriptional transposon silencing in Drosophila

2021-01-26 | PXD022103 | Pride

The dimeric SFiNX complex enables piRNA-guided co-transcriptional silencing through molecular condensate formation

Project description:Nuclear Argonaute proteins, guided by their bound small RNAs, orchestrate heterochromatin formation at transposon insertions and repetitive genomic loci. The molecular mechanisms that, besides recruiting heterochromatin effector proteins, are required for this silencing process are poorly understood. Here, we show that the SFiNX complex, the central silencing mediator downstream of nuclear Piwi-piRNA complexes in Drosophila, enables co-transcriptional silencing via the formation of molecular condensates. Condensate formation is stimulated by nucleic acid binding and requires SFiNX to form a homodimer. The dynein light chain dLC8, a highly conserved dimerization hub protein, mediates homo-dimerization of SFiNX. Point mutations preventing dLC8-mediated SFiNX dimerization result in transposon de-repression and sterility. dLC8’s function can be bypassed with a heterologous dimerization domain, suggesting that dimerization is a constitutive rather than a regulated feature of SFiNX. We propose that nucleic-acid stimulated condensate formation enables co-transcriptional silencing through the retention of the target RNA at chromatin, thereby allowing effector proteins to establish heterochromatin at the target locus.

2021-02-12 | PXD022010 | Pride

Molecular principles of Piwi-mediated cotranscriptional silencing through the dimeric SFiNX complex

Project description:Nuclear Argonaute proteins, guided by their bound small RNAs to nascent target transcripts, mediate cotranscriptional silencing of transposons and repetitive genomic loci through heterochromatin formation. The molecular mechanisms involved in this process are incompletely understood. Here, we show that the SFiNX complex, a silencing mediator downstream from nuclear Piwi-piRNA complexes in Drosophila, facilitates cotranscriptional silencing as a homodimer. The dynein light chain protein Cut up/LC8 mediates SFiNX dimerization, and its function can be bypassed by a heterologous dimerization domain, arguing for a constitutive SFiNX dimer. Dimeric, but not monomeric SFiNX, is capable of forming molecular condensates in a nucleic acid-stimulated manner. Mutations that prevent SFiNX dimerization result in loss of condensate formation in vitro and the inability of Piwi to initiate heterochromatin formation and silence transposons in vivo. We propose that multivalent SFiNX-nucleic acid interactions are critical for heterochromatin establishment at piRNA target loci in a cotranscriptional manner.

2020-12-31 | GSE159424 | GEO

Dimerisation of the PICTS complex via LC8/Cut-up drives co-transcriptional transposon silencing in Drosophila [RNA-Seq]

2021-01-25 | GSE160859 | GEO