Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Transcriptional coupling of telomeric retrotransposons with the cell cycle

ABSTRACT: Instead of employing telomerases to safeguard chromosome ends, dipteran species maintain their telomeres by transposition of telomeric-specific retrotransposons (TRs): in Drosophila, these are HeT-A, TART, and TAHRE. Previous studies have shown how these TRs create tandem repeats at chromosome ends, but the exact mechanism controlling TR transcription has remained unclear. Here we report the identification of multiple subunits of the transcription cofactor Mediator complex and transcriptional factors Scalloped (Sd, the TEAD homolog in flies) and E2F1-Dp as novel regulators of TR transcription and telomere length in Drosophila. Depletion of multiple Mediator subunits, Dp, or Sd increased TR expression and telomere length, while over-expressing E2F1-Dp or knocking down the E2F1 regulator Rbf1 (Retinoblastoma-family protein 1) stimulated TR transcription, with Mediator and Sd affecting TR expression through E2F1-Dp. The CUT&RUN analysis revealed direct binding of CDK8, Dp, and Sd to telomeric repeats. These findings highlight the essential role of the Mediator complex in maintaining telomere homeostasis by regulating TR transcription through E2F1-Dp and Sd, revealing the intricate coupling of TR transcription with the host cell-cycle machinery, thereby ensuring chromosome end protection and genomic stability during cell division.

ORGANISM(S): Drosophila melanogaster

PROVIDER: GSE278499 | GEO | 2024/11/27

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Transcriptional coupling of telomeric retrotransposons with the cell cycle [CUT&RUN]

Project description:Instead of employing telomerases to safeguard chromosome ends, dipteran species maintain their telomeres by transposition of telomeric-specific retrotransposons (TRs): in Drosophila, these are HeT-A, TART, and TAHRE. Previous studies have shown how these TRs create tandem repeats at chromosome ends, but the exact mechanism controlling TR transcription has remained unclear. Here we report the identification of multiple subunits of the transcription cofactor Mediator complex and transcriptional factors Scalloped (Sd, the TEAD homolog in flies) and E2F1-Dp as novel regulators of TR transcription and telomere length in Drosophila. Depletion of multiple Mediator subunits, Dp, or Sd increased TR expression and telomere length, while over-expressing E2F1-Dp or knocking down the E2F1 regulator Rbf1 (Retinoblastoma-family protein 1) stimulated TR transcription, with Mediator and Sd affecting TR expression through E2F1-Dp. The CUT&RUN analysis revealed direct binding of CDK8, Dp, and Sd to telomeric repeats. These findings highlight the essential role of the Mediator complex in maintaining telomere homeostasis by regulating TR transcription through E2F1-Dp and Sd, revealing the intricate coupling of TR transcription with the host cell-cycle machinery, thereby ensuring chromosome end protection and genomic stability during cell division.

2024-11-27 | GSE280471 | GEO

Transformation-induced stress at telomeres is counteracted through changes in the telomeric proteome including SAMHD1

Project description:Telomeres play crucial roles during tumorigenesis inducing cellular senescence upon telomere shortening and extensive chromosome instability during telomere crisis. However, it has not been investigated if and how cellular transformation and oncogenic stress alters telomeric chromatin composition and function. Here we transform human fibroblasts by consecutive transduction with vectors expressing hTERT, the SV40 early region and activated H-RasV12. Pairwise comparisons of the telomeric proteome during different stages of transformation reveals upregulation of proteins involved in chromatin remodeling, DNA repair and replication at chromosome ends. Depletion of several of these proteins induces telomere fragility indicating their roles in replication of telomeric DNA. Depletion of SAMHD1, which has reported roles in DNA resection and homology directed repair, leads to telomere breakage events in cells deprived of the shelterin component TRF1. Thus our analysis identifies factors, which accumulate at telomeres during cellular transformation to promote telomere replication and repair, resisting oncogene-borne telomere replication stress.

2018-07-13 | PXD010088 | Pride

Proteomic analysis defines the interactome of telomerase in the protozoan parasite, Trypanosoma brucei

Project description:Telomeres are the nucleoprotein structures found at the ends of eukaryotic chromosomes. Conventional DNA polymerases are unable to fully replicate the telomeric end of the chromosome, which leads to a progressive loss of DNA after every cell division. This problem is solved by the ribonucleoprotein enzyme, telomerase. Proper maintenance of the telomeric end is critical for maintaining genome integrity in eukaryotes. The telomerase enzyme has two essential components: the telomerase RNA (TR), which provides the template required for telomeric DNA synthesis; and the catalytic protein telomerase reverse transcriptase (TERT) that catalyzes the extension of the telomeric DNA ends using the TR as a template. The action of telomerase prevents the progressive shortening of the telomeres after every cell division. The TR can form a large structural scaffold upon which many accessory proteins can bind to and form the complete telomerase holoenzyme in vivo. These accessory proteins are required for telomerase activity and regulation inside of cells. The interacting partners of the TERT protein have been extensively characterized in yeast, human, and Tetrahymena systems. These interactors have not been extensively studied in lower eukaryotes including clinically relevant human parasites, such as Trypanosoma brucei (T. brucei). To this end, we performed co-immunoprecipitation coupled to LC-MS/MS of TbTERT-FLAG-HA-HA from T. brucei cells using an anti-TbTERT antibody and protein G magnetic beads. An isotype matched IgG control was performed in tandem. Comparisons of enriched proteins in the IP vs. IgG control revealed previously known and novel interactors of TbTERT. These findings suggest potential mechanistic differences in telomere maintenance in T. brucei compared to higher eukaryotes.

2023-03-08 | PXD038235 | Pride

Mutant thyroid hormone receptors (TRs) isolated from distinct cancer types display distinct target gene specificities: a unique regulatory repertoire associated with renal clear cell carcinomas.

Project description:Thyroid hormone receptors (TRs) are hormone-regulated transcription factors that regulate a diverse array of biological activities, including metabolism, homeostasis, and development. TRs also serve as tumor suppressors, and aberrant TR function (via mutation, deletion, or altered expression) is associated with a spectrum of both neoplastic and endocrine diseases. A particularly high frequency of TR mutations has been reported in renal clear cell carcinoma (RCCC) and in hepatocellular carcinoma (HCC). We have shown that HCC-TR mutants regulate only a fraction of the genes targeted by wild-type TRs, but have gained the ability to regulate other, unique, targets. We have suggested that this altered gene recognition may contribute to the neoplastic phenotype. Here, to determine the generality of this phenomenon, we examined a distinct set of TR mutants associated with RCCCs. We report that two different TR mutants, isolated from independent RCCC tumors, possess greatly expanded target gene specificities that extensively overlap one another, but only minimally overlap that of the WT-TRs, or those of two HCC-TR mutants. Many of the genes targeted by either or both RCCC-TR mutants have been previously implicated in RCCC, and include a series of metallothioneins, solute carriers, and genes involved in glycolysis and energy metabolism. We propose that TR mutations from RCCC and HCC are likely to play tissue-specific roles in carcinogenesis, and that the divergent target gene recognition patterns of TR mutants isolated from the two different types of tumors arises from different selective pressures during development of RCCC versus HCC. Gene expression was analyzed in HepG2 transformants expressing ectopic wildtype THRA, wildtype THRB, HCC-TR mutants ?? and ?N, and RCCC-TR mutants 6? and 15? using Affymetrix Human Gene 1.0 ST arrays in the presence or absence of T3. Each HepG2 transformant was assayed in triplicate.

2011-05-10 | E-GEOD-29159 | biostudies-arrayexpress

Chromatin modifiers and recombination factors promote a telomere fold-back structure, that is lost during replicative senescence

Project description:Telomeres have the ability to adopt a lariat conformation and hence, engage in long and short distance intra-chromosome interactions. Budding yeast telomeres were proposed to fold back into subtelomeric regions, but a robust assay to quantitatively characterize this structure has been lacking. Therefore, it is not well understood how the interactions between telomeres and non-telomeric regions are established and regulated. We employ a telomere chromosome conformation capture (Telo-3C)approach to directly analyze telomere folding and its maintenance in S. cerevisiae. We identify the histone modifiers Sir2, Sin3 and Set2 as critical regulators for telomere folding, which suggests that a distinct telomeric chromatin environment is a major requirement for the folding of yeast telomeres. We demonstrate that telomeres are not folded when cells enter replicative senescence, which occurs independently of short telomere length. Indeed, Sir2, Sin3 and Set2 protein levels are decreased during senescence and their absence may thereby prevent telomere folding. Additionally, we show that the homologous recombination machinery, including the Rad51 and Rad52 proteins, as well as the checkpoint component Rad53 are essential for establishing the telomere fold-back structure. This study outlines a method to interrogate telomere-subtelomere interactions at a single unmodified yeast telomere. Using this method, we provide insights into how the spatial arrangement of the chromosome end structure is established and demonstrate that telomere folding is compromised throughout replicative senescence.

2020-11-20 | PXD021085 | Pride

Mutant thyroid hormone receptors (TRs) isolated from distinct cancer types display distinct target gene specificities: a unique regulatory repertoire associated with renal clear cell carcinomas.

2011-05-10 | GSE29159 | GEO

Epigenomic landscapes of human inflammation associated macrophages [RNA-seq]

Project description:We previously demonstrated by genomic and bioinformatical approaches that human macrophage (MÎ¦) activation is best described by a spectrum model (Xue et al, Immunity, 2014). MÎ¦ integrate exogenous input signals on transcriptional level in a unique fashion to generate specific functional programs, enabling the plasticity in disease-related pathophysiologies. Such versatile responsiveness requires fast changes of transcription mediated by transcriptional regulators (TRs) or epigenomic changes. To better understand the principles of this regulation during human MÎ¦ activation, we assessed histone modifications including H3K4me1, H3K4me3, H3K27me3, and H3K27Ac by ChIP-sequencing allowing us to characterize the functional state of promoters (active, poised, repressed) and enhancers (active, inactive, intermediate). Using transcriptome data from our MÎ¦ spectrum model, we generated a co-regulation network of all TRs. Next, we overlaid epigenomic information and transcriptional changes of major TRs over time onto the TR network. We observed that input signals like IFNÎ³ or TNFÎ± induce a specific network of TRs that are transcriptionally regulated themselves, the combination of regulated TRs changes over time with a boost of transcriptional regulation of dozens of TRs 4 to 12 hrs post input signal exposure, almost all TRs within the network show active promoters, even if the TR itself is not expressed, and similar results are obtained for enhancers with open or at least intermediated states. These findings strongly suggest that in MÎ¦, the TR-defined cellular âswitch panelâ is always accessible thereby allowing MÎ¦ to quickly respond to the diverse input signal repertoire from the environment. Epigenetic analysis of promoter and enhancer sites in primary human macrophage subtypes and correlation to RNA-seq expression data

2016-02-28 | E-GEOD-66593 | biostudies-arrayexpress

Epigenomic landscapes of human inflammation associated macrophages [ChIP-seq]

Project description:We previously demonstrated by genomic and bioinformatical approaches that human macrophage (MÎ¦) activation is best described by a spectrum model (Xue et al, Immunity, 2014). MÎ¦ integrate exogenous input signals on transcriptional level in a unique fashion to generate specific functional programs, enabling the plasticity in disease-related pathophysiologies. Such versatile responsiveness requires fast changes of transcription mediated by transcriptional regulators (TRs) or epigenomic changes. To better understand the principles of this regulation during human MÎ¦ activation, we assessed histone modifications including H3K4me1, H3K4me3, H3K27me3, and H3K27Ac by ChIP-sequencing allowing us to characterize the functional state of promoters (active, poised, repressed) and enhancers (active, inactive, intermediate). Using transcriptome data from our MÎ¦ spectrum model, we generated a co-regulation network of all TRs. Next, we overlaid epigenomic information and transcriptional changes of major TRs over time onto the TR network. We observed that input signals like IFNÎ³ or TNFÎ± induce a specific network of TRs that are transcriptionally regulated themselves, the combination of regulated TRs changes over time with a boost of transcriptional regulation of dozens of TRs 4 to 12 hrs post input signal exposure, almost all TRs within the network show active promoters, even if the TR itself is not expressed, and similar results are obtained for enhancers with open or at least intermediated states. These findings strongly suggest that in MÎ¦, the TR-defined cellular â??switch panelâ?? is always accessible thereby allowing MÎ¦ to quickly respond to the diverse input signal repertoire from the environment. Epigenetic analysis of promoter and enhancer sites in primary human macrophage subtypes and correlation to RNA-seq expression data

2016-02-28 | E-GEOD-66594 | biostudies-arrayexpress

Mammalian telomeres reforged with non-telomeric sequences

Project description:Telomere is a highly refined system for maintaining the stability of linear chromosomes. Most telomeres rely on simple repetitive sequences and telomerase enzymes, but in some species or telomerase-defective situations, alternative telomere lengthening (ALT) mechanism is utilized to protect chromosomal ends. Telomere loss can induce telomere recombination by which specific sequences can be recruited into telomeres. However, canonical telomeric repeat-based telomeres have been found in mammals. Here, we show that mammalian telomeres can also be completely reconstituted using a non-telomeric unique sequence. We found that a specific subtelomeric element, named as mouse template for ALT (mTALT), is utilized for repairing telomeric DNA damage and composing new telomeric sequences in mouse embryonic stem cells. We found a high-level of non-coding mTALT transcript despite the heterochromatic nature of mTALT-based telomere. After ALT activation, the increased HMGN1, a non-histone chromosomal protein, contributed to maintaining telomere stability by regulating telomeric transcriptions. Our findings reveal novel molecular features of potential telomeric sequences which can reconstitute telomeres during cancer formation and evolution.

2020-07-17 | MSV000085772 | MassIVE

Human telomerase requires TCAB1 for catalytic function and for shaping RNA component conformation

Project description:Ribonucleoprotein enzymes require specific and dynamic conformations of their RNA constituents for regulated catalysis. Telomerase RNA components (TRs) rely on two conserved domains, a pseudoknot/template sequence and a three-way junction (CR4/5), each of which binds the telomerase reverse transcriptase protein (TERT). Vertebrate TRs evolved a third element, the H/ACA domain, involved in assembly and trafficking of telomerase through binding telomerase cofactors, dyskerin and TCAB1, respectively. Here, we show that telomerase unexpectedly requires TCAB1 for enzyme catalysis and for shaping the conformation of the TR CR4/5 domain. Human and mouse cells lacking TCAB1 exhibit a marked reduction in telomerase activity, but show no defect in enzyme assembly. Instead, loss of TCAB1 causes specific unfolding of critical RNA helices in TR CR4/5 required for catalysis, and impairs TR-TERT association. CR4/5 mutations derived from patients with the telomere disorder dyskeratosis congenita phenocopy the loss of enzyme activity and disruption of TERT binding observed with TCAB1 deletion. These findings show that the H/ACA element acquired by telomerase during vertebrate evolution serves an unanticipated role in controlling folding of the essential TR CR4/5 domain, facilitating optimal TERT engagement and enabling telomerase catalysis through the action of TCAB1 protein tethered at the H/ACA domain.

2018-06-24 | GSE97486 | GEO

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