Search results for "telomere"

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

2020

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 dis…

Short telomeres drive pessimistic judgement bias in zebrafish.

2021

The role of telomerase reverse transcriptase has been widely investigated in the contexts of ageing and age-related diseases. Interestingly, decreased telomerase activities (and accelerated telomere shortening) have also been reported in patients with emotion-related disorders, opening the possibility for subjective appraisal of stressful stimuli playing a key role in stress-driven telomere shortening. In fact, patients showing a pessimistic judgement bias have shorter telomeres. However, in humans the evidence for this is correlational and the causal directionality between pessimism and telomere shortening has not been established experimentally yet. We have developed and validated a judg…

The histone deacetylase Rpd3 regulates the heterochromatin structure of Drosophila telomeres

2011

Telomeres are specialized structures at the end of eukaryotic chromosomes that are required to preserve genome integrity, chromosome stability and nuclear architecture. Telomere maintenance and function are established epigenetically in several eukaryotes. However, the exact chromatin enzymatic modifications regulating telomere homeostasis are poorly understood. In Drosophila melanogaster, telomere length and stability are maintained through the retrotransposition of specialized telomeric sequences and by the specific loading of protecting capping proteins, respectively. Here, we show that the loss of the essential and evolutionarily conserved histone deacetylase Rpd3, the homolog of mammal…

Retrotransposon silencing and telomere integrity in somatic cells of Drosophila depends on the cytosine-5 methyltransferase DNMT2

2009

Here we show that the cytosine-5 methyltransferase DNMT2 controls retrotransposon silencing in Drosophila somatic cells. In Drosophila, significant DNMT2-dependent DNA methylation occurs during early embryogenesis. Suppression of white gene silencing by Mt2 (Dnmt2) null mutations in variegated P[w(+)] element insertions identified functional targets of DNMT2. The enzyme controls DNA methylation at retrotransposons in early embryos and initiates histone H4K20 trimethylation catalyzed by the SUV4-20 methyltransferase. In somatic cells, loss of DNMT2 eliminates H4K20 trimethylation at retrotransposons and impairs maintenance of retrotransposon silencing. In Dnmt2 and Suv4-20 null genotypes, re…

UbcD1: from telomere capping to global chromatin regulation

2012

DNA damage response at telomeres boosts the transcription of SARS-CoV-2 receptor ACE2 during aging

2021

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes the coronavirus disease 2019 (COVID-19), known to be more common in the elderly, who also show more severe symptoms and are at higher risk of hospitalization and death. Here, we show that the expression of the angiotensin converting enzyme 2 (ACE2), the SARS-CoV-2 cell receptor, increases during aging in mouse and human lungs. ACE2 expression increases upon telomere shortening or dysfunction in both cultured mammalian cells and in vivo in mice. This increase is controlled at the transcriptional level, and Ace2 promoter activity is DNA damage response (DDR)-dependent. Both pharmacological global DDR inhibition of ATM kin…

FISH mapping of 18S rDNA and (TTAGGG)n sequences in two pipefish species (Gasteroisteiformes: Syngnathidae).

2006

1Istituto di Scienze Marine, Sezione di Venezia, CNR, Castello 1364/a, 30122 Venezia, Italy 2Dipartimento di Biologia Animale, Universita di Palermo, Via Archirafi 18, 90123 Palermo, Italy 3Dipartimento di Scienze Ambientali, Universita “Ca’ Foscari”, Castello 2737/b 30122 Venezia, Italy 4Istituto di Ecologia e Biologia Ambientale, Universita di Urbino “Carlo Bo”, Via I. Maggetti 22, 61029 Urbino (PU), Italy

Telomere length in cervical smears of women with high-risk human papillomavirus (HPV HR)

2018

A Radical Signal Activates the Epigenetic Regulation of Longevity

2013

Hormesis is an adaptive stress response implicated in longevity regulation. Schroeder et al. (2013) have now connected stress, epigenetic changes, and aging in yeast by showing that mitochondria-derived reactive oxygen species modulate the chromatin binding capacity of the histone demethylase Rph1p at subtelomeres, resulting in lifespan extension.

Senescence and p130/Rbl2: a new beginning to the end.

2009

Senescence is the process of cellular aging dependent on the normal physiological functions of non-immortalized cells. With increasing data being uncovered in this field, the complex molecular web regulating senescence is gradually being unraveled. Recent studies have suggested two main phases of senescence, the triggering of senescence and the maintenance of senescence. Each has been supported by data implying precise roles for DNA methyltransferases, reactive oxygen species and other factors. We will first summarize the data supporting these claims and then highlight the specific role that we hypothesize that p130/Rbl2 plays in the modulation of the senescence process.