Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

The RRM-mediated RNA binding activity in T. brucei RAP1 is essential for VSG monoallelic expression

ABSTRACT: Trypanosoma brucei is a protozoan parasite that causes human African trypanosomiasis. Its major surface antigen VSG is expressed from subtelomeric loci in a strictly monoallelic manner. We previously showed that the telomere protein TbRAP1 binds dsDNA through its 737RKRRR741 patch to silence VSGs globally. How TbRAP1 permits transcription of the single active VSG is unknown. Through NMR structural analysis, we unexpectedly identify an RNA Recognition Motif (RRM) in TbRAP1, which is unprecedented for RAP1 homologs. Assisted by the 737RKRRR741 patch, TbRAP1 RRM recognizes consensus sequences of VSG 3’UTRs in vitro and binds the active VSG RNA in vivo. Mutating conserved RRM residues abolishes the RNA binding activity, significantly decreases the active VSG RNA level, and derepresses silent VSGs. The competition between TbRAP1’s RNA and dsDNA binding activities suggests a novel mechanism of monoallelic expression, in which the active VSG’s abundant RNA antagonizes TbRAP1’s silencing effect, thereby sustaining its full-level transcription.

ORGANISM(S): Trypanosoma brucei brucei

PROVIDER: GSE193394 | GEO | 2023/02/17

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

The RRM-mediated RNA binding activity in T. brucei RAP1 is essential for VSG monoallelic expression

Project description:The RRM-mediated RNA binding activity in T. brucei RAP1 is essential for VSG monoallelic expression

| PRJNA796023 | ENA

Up regulated Variant Surface Glycoproteins under TDP1 overexpression

Project description:Trypanosoma brucei parasites successfully evade the host immune system by periodically switching the dense coat of Variant Surface Glycoproteins (VSG) at the cell surface. Each parasite expresses VSGs in a monoallelic fashion that is tightly regulated. The consequences of exposing multiple VSGs during an infection in terms of antibody response and disease severity remain unknown. In this study, we overexpressed a high mobility group box protein, TDP1, which was sufficient to open the chromatin of silent VSG expression sites, to disrupt VSG monoallelic expression and to generate viable and healthy parasites with a mixed VSG coat. Mice infected with these parasites mounted a multi-VSG antibody response, which rapidly reduced parasitemia. Consequently, we observed a prolonged mice survival in which nearly 90% of the mice survived a 30-day period infection with undetectable parasitemia. Immunodeficient RAG2 knock-out mice were unable to control the infection with TDP1-overexpressing parasites, showing that the adaptive immune response is critical to reduce disease severity. This study shows that simultaneous exposure of multiple VSGs is highly detrimental for the parasite even at the very early stages of infection, suggesting that drugs that disrupt VSG monoallelic expression could be used to treat trypanosomiasis.

2019-09-13 | PXD014803 | Pride

VSG seq T. brucei

Project description:Sequencing of the expressed VSGs in T. brucei cells where monoallelic VSG expression has been disrupted.

| PRJEB43907 | ENA

POLIE suppresses telomerase-mediated telomere G-strand extension and helps ensure proper telomere C-strand synthesis in trypanosomes

Project description:T. brucei regularly switches its major surface antigen, VSG, to evade the mammalian host immune response. VSGs are expressed from subtelomeric loci in a strictly monoallelic manner. We identify POLIE as an intrinsic component of the T. brucei telomere complex and examined the effect of POLIE depletion on VSG expression regulation by RNAseq.

2022-01-07 | GSE182941 | GEO

Application of long read sequencing to determine expressed antigen diversity in Trypanosoma brucei infections.

Project description:Antigenic variation is employed by many pathogens to evade the host immune response, and Trypanosoma brucei has evolved a complex system to achieve this phenotype, involving sequential use of variant surface glycoprotein (VSG) genes encoded from a large repertoire of ~2,000 alleles. T. brucei express multiple, sometimes closely related, VSGs in a population at any one time, and the ability to resolve and analyse this diversity has been limited. We applied long read sequencing (PacBio) to VSG amplicons generated from blood extracted from batches of mice sacrificed at time points (days 3, 6, 10 and 12) post-infection with T. brucei TREU927. The data showed that long read sequencing is reliable for resolving allelic differences between VSGs, and demonstrated that there is significant expressed diversity (449 VSGs detected across 20 mice) and across the timeframe of study there was a clear semi-reproducible pattern of expressed diversity (median of 27 VSGs per sample at day 3 post infection (p.i.), 82 VSGs at day 6 p.i., 187 VSGs at day 10 p.i. and 132 VSGs by day 12 p.i.). There was also consistent detection of one VSG dominating expression across replicates at days 3 and 6, and emergence of a second dominant VSG across replicates by day 12, providing further evidence for hierarchical VSG expression, a conclusion that was confirmed by the novel application of diversity analysis to VSG expression. Our results indicate that long read analysis is a reliable tool for resolving diverse allele expression profiles, and provides novel insights into the complexity and nature of VSG expression in trypanosomes, revealing significantly higher diversity than previously shown and identifying mosaic gene formation unprecedentedly early during the infection process.

2018-11-01 | GSE114843 | GEO

Quadruple rrm experience - Transcriptomic study of a quadruple rrm mutant which belong to a new family of AGO hook proteins

Project description:rs10-01_rrm - quadruple rrm experience - What is the role of the RRM protein family in plants? Plants were grown on soil in controlled environment under LD (16 h light/8 h dark) and the rosette leaves (8-leaf stage seedlings) were collected for RNA preparation. Keywords: normal vs transgenic comparison

2011-04-16 | GSE21701 | GEO

RRM transcriptomic analysis

Project description:Screening of genes regulated between two grapevine genotypes (the Carignan and the RRM) during early inflorescence development

2009-12-08 | E-MEXP-1950 | biostudies-arrayexpress

Quadruple rrm experience - Transcriptomic study of a quadruple rrm mutant which belong to a new family of AGO hook proteins

2011-04-16 | E-GEOD-21701 | biostudies-arrayexpress

TbSAP is a novel chromatin protein repressing metacyclic Variant Surface Glycoprotein expression sites in bloodstream form Trypanosoma brucei

Project description:The African trypanosome Trypanosoma brucei is a unicellular eukaryote, which relies on a protective Variant Surface Glycoprotein (VSG) coat for survival in the mammalian host. A single trypanosome has >2000 VSG genes and pseudogenes of which only one is expressed from one of ~15 telomeric bloodstream form expression sites (BESs). Infectious metacyclic trypanosomes present within the tsetse fly vector also express VSG from a separate set of telomeric metacyclic ESs (MESs). All MESs are silenced in bloodstream form T. brucei. As very little is known about how this is mediated, we performed a whole genome RNAi library screen to identify MES repressors. This allowed us to identify a novel SAP domain containing DNA binding protein which we called TbSAP. TbSAP is enriched at the nuclear periphery and binds both MESs and BESs. Knockdown of TbSAP in bloodstream form trypanosomes did not result in cells becoming more ‘metacyclic’-like. Instead, there was extensive global upregulation of transcripts including MES VSGs, VSGs within the silent VSG arrays as well as genes immediately downstream of BES promoters. TbSAP therefore appears to be a novel architectural chromatin protein playing an important role in silencing the extensive VSG repertoire of bloodstream form T. brucei.

2020-11-04 | GSE160713 | GEO

A DOT1B/RH2 protein complex is involved in R-loop processing, genomic integrity and antigenic variation in Trypanosoma brucei

Project description:The parasite Trypanosoma brucei periodically changes the expression of protective variant surface glycoproteins (VSGs) to evade its host’s immune system in a process known as antigenic variation. One route to change VSG expression is the transcriptional activation of a previously silent VSG expression site (ES), a subtelomeric region containing the VSG genes. Homologous recombination of a different VSG from a large reservoir into the active ES represents another route. The conserved histone methyltransferase DOT1B is involved in transcriptional silencing of inactive ES and influences ES switching kinetics. The molecular machinery that enables DOT1B to execute these regulatory functions remains elusive, however. To better understand DOT1B-mediated regulatory processes, we purified DOT1B-associated proteins using complementary biochemical approaches. We identified several novel DOT1B-interactors. One of these was the Ribonuclease H2 complex, previously shown to resolve RNA-DNA hybrids, maintain genome integrity, and play a role in antigenic variation. Our study revealed that DOT1B depletion results in an increase in RNA-DNA hybrids, accumulation of DNA damage and ES switching events. Surprisingly, a similar pattern of VSG deregulation was observed in Ribonuclease H2 mutants. We propose that both proteins act together in resolving R-loops to ensure genome integrity and contribute to the tightly-regulated process of antigenic variation.

2021-10-25 | PXD028588 | Pride

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data