Mouse HP1γ regulates TRF1 expression and telomere stability
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ABSTRACT:
PROVIDER: PRJNA1003795 | ENA |
REPOSITORIES: ENA
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Project description:Telomeric Repeat-containing RNA are long non-coding RNAs generated from the telomeres. TERRAs are essential for the establishment of heterochromatin marks at telomeres, which serve for the binding of members of the Heterochromatin Protein 1protein family of epigenetic modifiers involved with chromatin compaction and gene silencing. While HP1γ is enriched on gene bodies of actively transcribed mammalian genes, it is unclear if its transcriptional role is important for HP1γ function in telomere cohesion and telomere maintenance. We aimed to study the effect of mouse HP1γ on the transcription of telomere factors and molecules that can affect telomere maintenance. We investigated the telomere function of HP1γ by using HP1γ deficient mouse embryonic fibroblastsderiving from 13.5 embryonic day embryos compared to their littermate controls. We used gene expression analysis of HP1γ deficient MEFs and validated the molecular and mechanistic consequences of HP1γ loss by telomere FISH, immunofluorescence, RT-qPCR and DNA-RNA Immunoprecipitation. Loss of HP1γ in primary MEFs led to a downregulation of various telomere and telomere-accessory transcripts, including the shelterin protein TRF1. Its downregulation is associated with increased telomere replication stress and DNA damage (γH2AX), effects more profound in females. We suggest that the source for the impaired telomere maintenance is a consequence of increased telomeric DNARNA hybrids and TERRAs arising at and from mouse chromosomes 18 and X. Our results suggest an important transcriptional control by mouse HP1γ of various telomere factors including TRF1 protein and TERRAs that has profound consequences on telomere stability, with a potential sexually dimorphic nature.
2023-08-19 | GSE240434 | GEO
Project description:The heterochromatin protein 1 (HP1) family members are canonical effectors and propagators of gene repression mediated by histone H3 lysine 9 (H3K9) methylation. HP1γ exhibits an increased interaction with active transcription elongation-associated factors in embryonic stem cells (ESCs) compared to somatic cells. However, whether this association has a functional consequence remains elusive. Here we find that genic HP1γ colocalizes and enhances enrichment of transcription elongation-associated H3K36me3 rather than H3K9me3. Unexpectedly, sustained H3K36me3 deposition is dependent on HP1γ. HP1γ-deleted ESCs display reduced H3K36me3 enrichment, concomitant with decreased expression at shared genes which function to maintain cellular homeostasis. Both the H3K9me3-binding chromodomain and histone binding ability of HP1γ are dispensable for maintaining H3K36me3 levels. Instead, the chromoshadow together with the hinge domain of HP1γ that confer protein and nucleic acid-binding ability are sufficient because they retain the ability to interact with NSD1, an H3K36 methyltransferase. HP1γ-deleted ESCs have a slower self-renewal rate and an impaired ability to differentiate towards cardiac mesoderm. Our findings reveal a requirement for HP1γ in faithful establishment of transcription elongation in ESCs, which regulates pluripotency.
2020-11-01 | GSE144862 | GEO
Project description:The heterochromatin protein 1 (HP1) family members are canonical effectors and propagators of gene repression mediated by histone H3 lysine 9 (H3K9) methylation. HP1γ exhibits an increased interaction with active transcription elongation-associated factors in embryonic stem cells (ESCs) compared to somatic cells. However, whether this association has a functional consequence remains elusive. Here we find that genic HP1γ colocalizes and enhances enrichment of transcription elongation-associated H3K36me3 rather than H3K9me3. Unexpectedly, sustained H3K36me3 deposition is dependent on HP1γ. HP1γ-deleted ESCs display reduced H3K36me3 enrichment, concomitant with decreased expression at shared genes which function to maintain cellular homeostasis. Both the H3K9me3-binding chromodomain and histone binding ability of HP1γ are dispensable for maintaining H3K36me3 levels. Instead, the chromoshadow together with the hinge domain of HP1γ that confer protein and nucleic acid-binding ability are sufficient because they retain the ability to interact with NSD1, an H3K36 methyltransferase. HP1γ-deleted ESCs have a slower self-renewal rate and an impaired ability to differentiate towards cardiac mesoderm. Our findings reveal a requirement for HP1γ in faithful establishment of transcription elongation in ESCs, which regulates pluripotency.
2020-11-01 | GSE144861 | GEO
Project description:The naked mole rat (NMR), a long-lived and cancer resistant rodent, is highly resistant to hypoxia. Here, using robust cellular models wherein the mouse telomeric protein TRF1 is substituted by the NMR TRF1 or its mutant forms, we show that TRF1 supports maximal glycolytic capacity under low oxygen, shows increased nuclear localization and association with telomeres, and protects telomeres from replicative stress. We pinpoint this evolutionary gain of metabolic function to specific amino acid changes in the homodimerization domain of this protein. We further find that NMR TRF1 accelerates telomere shortening. These findings reveal an evolutionary strategy to adapt telomere biology for metabolic control under an extreme environment.
2021-03-02 | GSE163064 | GEO
Project description:For analysis of genes regulated by HP1γ in LUAD, we used microarray analysis to determine the global changes in gene expression upon HP1γ knockdown in H1792 cells and identified distinct sets of up-regulated and down-regulated genes upon depletion of HP1γ.
2018-11-13 | GSE111321 | GEO
Project description:HP1γ regulates H3K36 methylation and pluripotency in embryonic stem cells
| PRJNA605165 | ENA
Project description:Telomeric repeat sequences are prone to induce replication stress and one of the core telomere binding proteins, TRF1, is thought to counteract these problems. The molecular mechanisms coming into play upon TRF1 loss were not clearly defined though. This study combines an inducible TRF1 loss with telomere-targeted proteomics to analyze the incurring changes. The results show that loss of TRF1 causes important alterations in telomere associated proteins and the new profile resembles in a number of ways that of cells in which telomeres are maintained by telomerase-independent mechanisms, named ALT. The presence of DNA repair proteins (MRN complex, the SMC5/6 complex), some increases in telomere colocalization with PML bodies, sister chromatid exchanges and clear signs of increased TERRA transcription and mitotic break-induced replication are part of these phenotypes. The data also show that these early ALT phenotypes can be differentiated from drug induced replication stress, and part of this ALT response is conserved in human cells. These studies therefore point to a critical role for TRF1 in preventing the emergence of ALT and hence immortalization of cells. Given that the details for how ALT actually is initiated remained unclear, these findings are an important step forward and will spur new research into that question.
2020-01-22 | PXD017022 | Pride
Project description:Telomere length heterogeneity in various cell types including stem cells and cancer cells has been recognized. Cell heterogeneity also is found in pluripotent stem cells such as embryonic stem cells (ESCs). The implication and mechanisms underlying the heterogeneity remain to be defined. We have optimized a robust method that can simultaneously measure telomere length coupled with RNA-sequencing analysis (scT&R-seq) in the same human ES cell. Using this method, we show that telomere length varies with pluripotency state. Long telomere hESCs highly express TERF1/TRF1 as well as ZFP42/REX1, PRDM14 and NANOG for naïve pluripotency, in contrast to short telomere hESCs. hESCs express high telomerase activity as expected, and ubiquitously express NOP10 and DKC1, stabilizing components of telomerase complexes, regardless of telomere lengths. Moreover, new candidate genes such as MELK, MSH6 and UBQLN1 cluster with long telomeres and pluripotency network. Notably, short telomere hESCs exhibit higher oxidative phosphorylation primed for lineage differentiation, whereas long telomere hESCs show elevated glycolysis, another key feature for naïve pluripotency. Our data further suggest that telomere length is implicated in metabolism activity and pluripotency state of hESCs. Single cell analysis of telomere and RNA-sequencing can be exploited to further understand the molecular mechanisms of telomere heterogeneity.
2017-11-06 | GSE98644 | GEO
Project description:Telomere dysfunction in type II AECs, mediated by deletion of the telomere shelterin protein TRF1, leads to spontaneous development of pulmonary fibrosis in mice (SPC-creTRF1flox/flox mice). We sought to identify gene signature in these lungs in an effort to understand molecular mechanisms of the disease.
2018-11-28 | GSE114005 | GEO
Project description:HP1γ regulates H3K36 methylation and pluripotency in embryonic stem cells (ChIP-Seq)
| PRJNA605172 | ENA