ZNF524 directly binds telomeres and supports their integrity via TRF2/RAP1
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ABSTRACT:
PROVIDER: PRJNA806777 | ENA |
REPOSITORIES: ENA
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Project description:Telomeres are nucleoprotein structures at the ends of linear chromosomes. In humans, they consist of TTAGGG repeats, which are bound by dedicated proteins such as the shelterin complex. This complex consists of six proteins (TRF1, TRF2, RAP1, POT1, TPP1 and TIN2) and blocks unwanted DNA damage repair at telomeres, e.g. by suppressing non-homologous end joining (NHEJ) through its subunit TRF2. While shelterin does not work autonomously, additional direct telomere binding proteins have been described to function in a supplementary role. We here describe ZNF524, a zinc finger protein that directly binds to telomeric repeats with nanomolar affinity and reveal the base-specific sequence recognition by co-crystallization with telomeric DNA. ZNF524 localizes to telomeres and specifically maintains the presence of the TRF2/RAP1 subcomplex at telomeres without affecting the other shelterin members. Loss of ZNF524 concomitantly results in an increase in DNA damage signaling and recombination events. Overall, we identified ZNF524 as a direct telomere binding protein and propose that ZNF524 is involved in the maintenance of telomere integrity by promoting TRF2/RAP1 subcomplex binding.
2023-10-22 | PXD031416 | Pride
Project description:Telomeres are nucleoprotein structures at the ends of linear chromosomes. In humans, they consist of TTAGGG repeats, which are bound by dedicated proteins such as the shelterin complex. This complex consists of six proteins (TRF1, TRF2, RAP1, POT1, TPP1 and TIN2) and blocks unwanted DNA damage repair at telomeres, e.g. by suppressing non-homologous end joining (NHEJ) through its subunit TRF2. While shelterin does not work autonomously, additional direct telomere binding proteins have been described to function in a supplementary role. We here describe ZNF524, a zinc finger protein that directly binds to telomeric repeats with nanomolar affinity and reveal the base-specific sequence recognition by co-crystallization with telomeric DNA. ZNF524 localizes to telomeres and specifically maintains the presence of the TRF2/RAP1 subcomplex at telomeres without affecting the other shelterin members. Loss of ZNF524 concomitantly results in an increase in DNA damage signaling and recombination events. Overall, we identified ZNF524 as a direct telomere binding protein and propose that ZNF524 is involved in the maintenance of telomere integrity by promoting TRF2/RAP1 subcomplex binding.
2023-10-21 | PXD024630 | Pride
Project description:Telomeres are nucleoprotein structures at the ends of linear chromosomes. In humans, they consist of TTAGGG repeats, which are bound by dedicated proteins such as the shelterin complex. This complex blocks unwanted DNA damage repair at telomeres, e.g. by suppressing non-homologous end joining (NHEJ) through its subunit TRF2. We here describe ZNF524, a zinc finger protein that directly binds telomeric repeats with nanomolar affinity and reveal the base-specific sequence recognition by co-crystallization with telomeric DNA. ZNF524 localizes to telomeres in vivo, as shown among other approaches by ChIP-seq analysis, and specifically maintains the presence of the TRF2/RAP1 subcomplex at telomeres without affecting the other shelterin members. Loss of ZNF524 concomitantly results in an increase in DNA damage signaling and recombination events. Overall, ZNF524 is a direct telomere-binding protein involved in the maintenance of telomere integrity.
2023-10-23 | GSE196661 | GEO
Project description:Telomeres are the ends of linear chromosomes and together with the shelterin complex present an essential feature for genome integrity. Vertebrate telomeres usually consist of hexameric TTAGGG repeats, however, in cells that use the alternative lengthening of telomeres (ALT) mechanism, variant repeat sequences are interspersed throughout telomeres. Previously, it was shown that NR2C/F transcription factors bind to TCAGGG variant repeats and contribute to telomere maintenance in ALT cells. While specific binders to other variant repeat sequences have been lacking to date, we here identify ZBTB10 as the first TTGGGG-binding protein and demonstrate direct binding via the two zinc fingers with affinity in the nanomolar range. Concomitantly, ZBTB10 co-localizes with a subset of telomeres in ALT-positive U2OS cells and interacts with TRF2/RAP1 via the N-terminal region of TRF2. Our data establishes ZBTB10 as a novel variant repeat-specific binding protein at ALT telomeres.
2018-12-17 | PXD010672 | Pride
Project description:Telomeres are nucleoprotein structures at the ends of linear chromosomes. In humans, they consist of TTAGGG repeats, which are bound by dedicated proteins such as the shelterin complex. This complex blocks unwanted DNA damage repair at telomeres, e.g. by suppressing non-homologous end joining (NHEJ) through its subunit TRF2. We here describe ZNF524, a zinc finger protein that directly binds telomeric repeats with nanomolar affinity and reveal the base-specific sequence recognition by co-crystallization with telomeric DNA. ZNF524 localizes to telomeres and specifically maintains the presence of the TRF2/RAP1 subcomplex at telomeres without affecting other shelterin members. Loss of ZNF524 concomitantly results in an increase in DNA damage signaling and recombination events. Overall, ZNF524 is a direct telomere-binding protein involved in the maintenance of telomere integrity.
2023-10-21 | PXD043084 | Pride
Project description:The conserved Rap1 protein is part of the shelterin complex that plays critical roles in chromosome end protection and telomere length homeostasis. Previous studies addressed how fission yeast Rap1 contributes to telomere length maintenance, but the mechanism by which the protein inhibits end fusions has remained elusive. Here, we use a genetic screen in combination with high throughput sequencing to identify several amino acid positions in Rap1 that have a key role in end protection. Interestingly, mutations at these sites render cells susceptible to genome instability in a conditional manner with longer telomeres being prone to undergoing end fusions, while short telomeres are sufficiently protected. The protection of long telomeres requires their nuclear envelope attachment mediated by the Rap1-Bqt4 interaction. Our data demonstrates that longer telomeres pose an additional challenge for the maintenance of genome integrity and provides an explanation for a species-specific upper limit in telomere length.
2022-08-10 | GSE190759 | GEO
Project description:Protein phosphatase magnesium-dependent 1 delta (PPM1D) is involved in termination of the cell cycle checkpoint by counteracting activity of the tumour suppressor protein p53. By dephosphorylating various proteins at chromatin, PPM1D contributes to the control of DNA damage response and DNA repair. Using proximity biotinylation followed by proteomic analysis, we identified interaction between PPM1D and the components of the shelterin complex that protects telomeric DNA. Interaction between PPM1D and TRF2 was confirmed by immunoprecipitation and proximity ligation assay. Confocal microscopy revealed colocalisation of the endogenous PPM1D with TRF2 at telomeres. Further, we found that TRF2 was phosphorylated by ATR at S410 after induction of DNA damage at telomeres and this modification was increased in cells lacking PPM1D or after PPM1D inhibition. Phosphorylation of TRF2 stimulated its interaction with TIN2 at telomeres and in vitro. Conversely, overexpression of PPM1D impaired localisation of TIN2 at telomeres. Finally, inhibition of PPM1D impaired recruitment of 53BP1 and RAD51 to DNA double strand breaks at telomeres. Expression of TRF2-S410A mutant fully rescued the recruitment of 53BP1 to telomeric breaks. These results suggest that TRF2 phosphorylation promotes association of TIN2 with the shelterin complex and regulates DNA repair at telomeres.
2023-03-11 | PXD035268 | Pride
Project description:Protein phosphatase magnesium-dependent 1 delta (PPM1D) terminates the cell cycle checkpoint by dephosphorylating the tumour suppressor protein p53. By targeting additional substrates at chromatin, PPM1D contributes to the control of DNA damage response and DNA repair. Using proximity biotinylation followed by proteomic analysis, we identified a novel interaction between PPM1D and the shelterin complex that protects telomeric DNA. In addition, confocal microscopy revealed that endogenous PPM1D colocalized with TRF2 at telomeres. Further, we found that ATR phosphorylated TRF2 at S410 after induction of DNA double strand breaks at telomeres and this modification increased after inhibition or loss of PPM1D. TRF2 phosphorylation stimulated its interaction with TIN2 both in vitro and at telomeres. Conversely, induced expression of PPM1D impaired localisation of TIN2 and TPP1 at telomeres. Finally, recruitment of the DNA repair factor 53BP1 to the telomeric breaks was strongly reduced after inhibition of PPM1D and was rescued by the expression of TRF2-S410A mutant. Our results suggest that TRF2 phosphorylation promotes the association of TIN2 within the shelterin complex and regulates DNA repair at telomeres.
2023-03-11 | PXD035273 | Pride
Project description:RAP1 is one of the components of mammalian shelterin, the capping complex at chromosome ends or telomeres, although its role in telomere protection has remained elusive. RAP1 binds along chromosome arms, where it regulates gene expression and has been shown to function in metabolism control. Telomerase is the enzyme that elongates telomeres and its deficiency causes a premature aging in mice. We describe an unanticipated genetic interaction between RAP1 and telomerase. While RAP1 deficiency alone does not impact in mouse survival, mice lacking both RAP1 and telomerase show a progressive decreased survival with increasing mouse generation as compared to telomerase single mutants. Telomere shortening was more pronounced in Rap1-/- Terc-/- than in Terc-/- counterparts, leading to an earlier onset of DNA damage and its consequent DNA damage response as well as accelerated degenerative pathologies in the intestines. In its turn, telomerase deficiency abolishes RAP1-mediated obesity and liver pathologies. Mouse embryonic fibroblasts with shorten telomeres present less amount of telomere-bound RAP1 but in contrast show higher numbers of RAP1 bound extratelomeric sites genomewide. Absence of RAP1 leads to deregulation of several metabolic pathways, and these changes were more pronounce in cells with short telomeres suggesting that RAP1 release from telomere foci could constitute a coordinated genomic response to telomere shortening. Our findings also demonstrate that although RAP1 is not a key factor in telomere capping under normal conditios, under stress situation such as critical telomere shortening RAP1 exerts an important function for telomere protection and justify its evolutionary conservation as a shelterin component in mammalian cells.
2016-11-16 | GSE79996 | GEO
Project description:By performing chromatin immunoprecipitation coupled with ultra-high-throughput sequencing (ChIP-seq), we find that RAP1 binds to telomeres as well as to extra-telomeric sites through the (TTAGGG)2 consensus motif. Extra-telomeric RAP1 binding sites are particularly abundant at subtelomeric regions, and this is in agreement with preferential deregulation of subtelomeric genes in Rap1-deficient cells. Significantly, more than 70% of extratelomeric RAP1 binding sites are located in the vicinity of known genes and about 40% of the genes deregulated in Rap1-null cells contain binding sites for RAP1, suggesting a role of RAP1 in transcriptional control. Examination of RAP1 binding by CHIP-seq in two independent wild-type mefs using as negative control two independent RAP1-deleted mefs
2010-07-10 | E-GEOD-20867 | biostudies-arrayexpress