ZNF365 promotes stability of fragile sites and telomeres
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE44599 | GEO | 2013/08/01
SECONDARY ACCESSION(S): PRJNA190672
REPOSITORIES: GEO
Similar Datasets
Project description:Critically short telomeres activate cellular senescence or apoptosis, as mediated by the tumor suppressor p53, but in the absence of this checkpoint response, telomere dysfunction engenders chromosomal aberrations and cancer. Here, analysis of p53-regulated genes activated in the setting of telomere dysfunction identified Zfp365 (ZNF365 in humans) as a direct p53 target that promotes genome stability. Germline polymorphisms in the ZNF365 locus are associated with increased cancer risk, including those associated with telomere dysfunction. On the mechanistic level, ZNF365 suppresses expression of a subset of common fragile sites (CFS) including telomeres. In the absence of ZNF365, defective telomeres engage in aberrant recombination of telomere ends, leading to increased telomere sister chromatid exchange (T-SCE) and formation of anaphase DNA bridges, including ultra-fine DNA bridges (UFB), and ultimately increased cytokinesis failure and aneuploidy. Thus, the p53-ZNF365 axis contributes to genomic stability in the setting of telomere dysfunction. We expressed an inducible p53 allele encoding a p53-estrogen receptor fusion protein (p53ER) that becomes functional upon addition of 4-hydroxytamoxifen (4-OHT) in TKO cells. We chose a time point of 4 hours post-4-OHT induction to catalog potential direct targets.
2013-08-01 | E-GEOD-44599 | biostudies-arrayexpress
Project description:The factors that underlie the increasing incidence of diabetes with age are poorly understood. We examined whether telomere length, known to decrease with age, plays a role in the age-dependent increased incidence of diabetes. We show that in mice with short telomeres, insulin secretion is impaired and leads to glucose intolerance despite the presence of an intact M-NM-2-cell mass. Islets from mice with short telomeres displayed evidence of M-NM-2-cell dysfunction, and in response to glucose, had defective mitochondrial membrane depolarization as well as Ca2+ handling which limited insulin release. Short telomeres induced the hallmarks of senescence including premature accumulation of p16INK4a, and altered gene expression of key pathways essential for signaling and insulin secretion. Short telomeres also had an additive damaging effect to endoplasmic reticulum stress which occurs in the late stages of type 2 diabetes. This manifested as more severe hyperglycemia in insulin mutant Akita mice which had a more profound loss of M-NM-2-cell mass and increased M-NM-2-cell apoptosis. Our data identify impaired signaling in the setting of senescence as a novel mechanism of telomere-mediated disease, and implicate telomere length as a determinant of risk and pathogenesis in diabetes. The experiment is designed to analyze gene expression profiles of islets from mice with short telomeres compared to those of wildtype mice.
2013-10-01 | E-GEOD-25040 | biostudies-arrayexpress
Project description:We performed single-molecule telomere length and telomere fusion analysis in patients at different stages of chronic lymphocytic leukaemia (CLL). Our work identified the shortest telomeres ever recorded in primary human tissue reinforcing the concept that there is significant cell division in CLL. Furthermore, we provide direct evidence that critical telomere shortening, dysfunction and fusion contribute to disease progression. The frequency of short telomeres and fusion events increased with advanced disease, but importantly these were also found in a subset of early-stage patient samples indicating that these events can precede disease progression. Sequence analysis of fusion events isolated from individuals with the shortest telomeres revealed limited numbers of repeats at the breakpoint, sub-telomeric deletion and microhomology. Array-CGH analysis of individuals displaying evidence of telomere dysfunction revealed large-scale genomic rearrangements that were concentrated in the telomeric regions; this was not observed in samples with longer telomeres. Array CGH was undertaken on six individuals (five CLL stage C and one stage A) that displayed evidence of telomere dysfunction, and four (three CLL stage A and one stage B) that displayed longer and apparently stable telomeres.
2010-05-28 | E-GEOD-22016 | biostudies-arrayexpress
Project description:Telomeres play vital roles in ensuring chromosome stability and are thus closely linked with the onset of aging and human disease. Telomeres undergo extensive lengthening during early embryogenesis through the so-called alternative lengthening of telomere (ALT) mechanism. However, the detailed molecular mechanism of telomere resetting in early embryos remains unknown. Here, we showed that Dcaf11 participates in telomere elongation in early embryos and 2-cell-like embryonic stem cells (ESCs) in a telomerase-independent manner. The deletion of Dcaf11 in embryos and ESCs leads to reduced telomere sister-chromatid exchange (T-SCE) and impairs telomere lengthening. Importantly, Dcaf11-deficient mice exhibit gradual telomere erosion with successive generations, and hematopoietic stem cell (HSC) activity is greatly compromised. Mechanistically, DCAF11 reactivates Zscan4 and facilitates the removal of heterochromatic H3K9me3 at telomere/subtelomere regions through targeting TRIM28 for ubiquitination-mediated degradation. Our study therefore demonstrates that the ALT factor Dcaf11 plays important roles in telomere elongation in early embryos and ESCs.
2021-01-01 | GSE132745 | GEO
Project description:Telomeres play vital roles in ensuring chromosome stability and are thus closely linked with the onset of aging and human disease. Telomeres undergo extensive lengthening during early embryogenesis. However, the detailed molecular mechanism of telomere resetting in early embryos remains unknown. Here, we show that Dcaf11 (Ddb1- and Cul4-associated factor 11) participates in telomere elongation in early embryos and 2-cell-like embryonic stem cells (ESCs). The deletion of Dcaf11 in embryos and ESCs leads to reduced telomere sister-chromatid exchange (T-SCE) and impairs telomere lengthening. Importantly, Dcaf11-deficient mice exhibit gradual telomere erosion with successive generations, and hematopoietic stem cell (HSC) activity is also greatly compromised. Mechanistically, Dcaf11 targets Kap1 (KRAB-associated protein 1) for ubiquitination-mediated degradation, leading to the activation of Zscan4 downstream enhancer and the removal of heterochromatic H3K9me3 at telomere/subtelomere regions. Our study therefore demonstrates that Dcaf11 plays important roles in telomere elongation in early embryos and ESCs through activating Zscan4.
2021-07-17 | GSE180259 | GEO
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
Project description:Telomere integrity is critical for embryonic development and core telomere-binding proteins such as TIN2 are key to maintaining telomere stability. Here we report that homozygous Tin2S341X resulted in embryonic lethality in mice and reduced expression of Tin2 in the derived mouse embryonic stem cells (mESCs). Homozygous mutant mESCs were able to self-renew and remain undifferentiated but displayed many phenotypes associated with alternative lengthening of telomeres (ALT), including excessively long and heterogeneous telomeres, increased ALT-associated PML bodies, and unstable chromosomal ends. These cells also showed upregulation of Zscan4 expression and elevated targeting of DAXX/ATRX and H3K9me3 marks on telomeres. Furthermore, the mutant mESCs were impeded in their differentiation capacity. Upon differentiation, DAXX/ATRX and PML bodies disassociated from telomeres in these cells, where elevated DNA damage was also apparent. Our results reveal differential responses to telomere dysfunction in mESCs versus differentiated cells and highlight the critical role of TIN2 in embryonic development.
2022-04-07 | GSE156514 | GEO
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. p53 binding was analyzed by ChIP-Seq in HCT116 cells treated with camptothecin or untreated control.
2016-01-07 | E-GEOD-75528 | biostudies-arrayexpress
Project description:The factors that underlie the increasing incidence of diabetes with age are poorly understood. We examined whether telomere length, known to decrease with age, plays a role in the age-dependent increased incidence of diabetes. We show that in mice with short telomeres, insulin secretion is impaired and leads to glucose intolerance despite the presence of an intact β-cell mass. Islets from mice with short telomeres displayed evidence of β-cell dysfunction, and in response to glucose, had defective mitochondrial membrane depolarization as well as Ca2+ handling which limited insulin release. Short telomeres induced the hallmarks of senescence including premature accumulation of p16INK4a, and altered gene expression of key pathways essential for signaling and insulin secretion. Short telomeres also had an additive damaging effect to endoplasmic reticulum stress which occurs in the late stages of type 2 diabetes. This manifested as more severe hyperglycemia in insulin mutant Akita mice which had a more profound loss of β-cell mass and increased β-cell apoptosis. Our data identify impaired signaling in the setting of senescence as a novel mechanism of telomere-mediated disease, and implicate telomere length as a determinant of risk and pathogenesis in diabetes.
2013-10-01 | GSE25040 | GEO
Project description:We performed single-molecule telomere length and telomere fusion analysis in patients at different stages of chronic lymphocytic leukaemia (CLL). Our work identified the shortest telomeres ever recorded in primary human tissue reinforcing the concept that there is significant cell division in CLL. Furthermore, we provide direct evidence that critical telomere shortening, dysfunction and fusion contribute to disease progression. The frequency of short telomeres and fusion events increased with advanced disease, but importantly these were also found in a subset of early-stage patient samples indicating that these events can precede disease progression. Sequence analysis of fusion events isolated from individuals with the shortest telomeres revealed limited numbers of repeats at the breakpoint, sub-telomeric deletion and microhomology. Array-CGH analysis of individuals displaying evidence of telomere dysfunction revealed large-scale genomic rearrangements that were concentrated in the telomeric regions; this was not observed in samples with longer telomeres.
2010-05-28 | GSE22016 | GEO