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Novel features of telomeres biology revealed by the absence of telomeric DNA methylation

ABSTRACT: Cytosine methylation regulates the length and stability of telomeres, which can affect a wide variety of biological features including cell differentiation, development or illness. Whereas it is well established that subtelomeric regions are methylated, the presence of methylated cytosines at telomeres has remained controversial. Here, we have analyzed multiple bisulfite sequencing studies to address the methylation status of Arabidopsis thaliana telomeres. We found that the levels of telomeric DNA methylation estimated varied among studies. Interestingly, we estimated higher levels of telomeric DNA methylation in studies that produced C-rich telomeric strands with lower efficiency. However, these high methylation estimates arose due to experimental limitations of the bisulfite technique. We found a similar phenomenom for mitochondrial DNA: the levels of mitochondrial DNA methylation detected were higher in experiments with lower mitochondrial read production efficiencies. Based on experiments with high telomeric C-rich strand production efficiencies, we concluded that Arabidopsis telomeres are not methylated, which was confirmed by methylation dependent restriction enzymes analyses. Thus, our studies indicate that telomeres are refractory to de novo DNA methylation by the RNA directed DNA methylation machinery. This result, together with previously reported data, reveals that subtelomeric DNA methylation controls the homeostasis of telomere length.

ORGANISM(S): synthetic construct

PROVIDER: GSE83510 | GEO | 2016/06/21

SECONDARY ACCESSION(S): PRJNA326221

REPOSITORIES: GEO

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Mammalian telomeres reforged with non-telomeric sequences

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2020-07-17 | MSV000085772 | MassIVE

ZBTB48 is both a vertebrate telomere-binding protein and a transcriptional activator

Project description:Telomeres constitute the ends of linear chromosomes and together with the shelterin complex form a structure essential for genome maintenance and stability. In addition to the constitutive binding of the shelterin complex, other direct, yet more transient interactions are mediated by the CST complex and HOT1, while subtelomeric variant repeats are recognized by NR2C/F transcription factors. Recently, the Kruppel-like zinc finger protein ZBTB48 has been described as a novel telomere-associated factor in the vertebrate lineage. Here, we show that ZBTB48 binds directly both to telomeric as well as to subtelomeric variant repeat sequences. ZBTB48 is found at telomeres of human cancer cells regardless of the mode of telomere maintenance and it acts as a negative regulator of telomere length. In addition to its telomeric function, we demonstrate through a combination of RNAseq, ChIPseq and expression proteomics experiments that ZBTB48 acts as a transcriptional activator on a small set of target genes, including mitochondrial fission process 1 (MTFP1). This discovery places ZBTB48 at the interface of telomere length regulation, transcriptional control and mitochondrial metabolism.

2017-05-11 | PXD006074 | Pride

Subtelomeric p53 Binding Prevents Accumulation of DNA Damage at Human Telomeres

Project description:Telomeres and tumor suppressor protein TP53 (p53) function in genome protection, but a direct role of p53 at telomeres has not yet been described. Here, we have identified non-canonical p53 binding sites within the human subtelomeres that suppress the accumulation of DNA damage at telomeric repeat DNA. These non-canonical subtelomeric p53 binding sites conferred transcription enhancer-like functions that include an increase in local histone H3K9 and H3K27 acetylation and stimulation of subtelomeric transcripts, including telomere-repeat containing RNA (TERRA). p53 suppressed formation of telomere-associated Î³H2AX and prevented telomere DNA degradation in response to DNA damage stress. Our findings indicate that p53 provides a direct chromatin-associated protection to human telomeres, as well as other fragile genomic sites. We propose that p53-associated chromatin modifications enhance local DNA repair or protection to provide a previously unrecognized tumor suppressor function of p53. p53 binding was analyzed by ChIP-Seq in HCT116 cells treated with camptothecin or untreated control.

2016-01-07 | E-GEOD-75528 | biostudies-arrayexpress

ZBTB48 is both a vertebrate telomere-binding protein and a transcriptional activator [RNA-seq]

Project description:Here we show that ZBTB48 binds directly both to telomeric as well as to subtelomeric variant repeat sequences. ZBTB48 is found at telomeres of human cancer cells regardless of the mode of telomere maintenance and it acts as a negative regulator of telomere length. In addition to its telomeric function, we demonstrate through a combination of RNAseq, ChIPseq and expression proteomics experiments that ZBTB48 acts as a transcriptional activator on a small set of target genes, including mitochondrial fission process 1 (MTFP1). This discovery places ZBTB48 at the interface of telomere length regulation, transcriptional control and mitochondrial metabolism.

2017-05-11 | GSE96777 | GEO

ZBTB48 is both a vertebrate telomere-binding protein and a transcriptional activator [ChIP-seq]

2017-05-11 | GSE96776 | GEO

Subtelomeric p53 Binding Prevents Accumulation of DNA Damage at Human Telomeres

Project description:Telomeres and tumor suppressor protein TP53 (p53) function in genome protection, but a direct role of p53 at telomeres has not yet been described. Here, we have identified non-canonical p53 binding sites within the human subtelomeres that suppress the accumulation of DNA damage at telomeric repeat DNA. These non-canonical subtelomeric p53 binding sites conferred transcription enhancer-like functions that include an increase in local histone H3K9 and H3K27 acetylation and stimulation of subtelomeric transcripts, including telomere-repeat containing RNA (TERRA). p53 suppressed formation of telomere-associated γH2AX and prevented telomere DNA degradation in response to DNA damage stress. Our findings indicate that p53 provides a direct chromatin-associated protection to human telomeres, as well as other fragile genomic sites. We propose that p53-associated chromatin modifications enhance local DNA repair or protection to provide a previously unrecognized tumor suppressor function of p53.

2016-01-07 | GSE75528 | GEO

The nucleoporin Nup170p is required for subtelomeric chromatin structure and gene silencing. [MNase-Seq]

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2013-02-28 | E-GEOD-36792 | biostudies-arrayexpress

Genome-wide maps of RAP1 binding sites.

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