Project description:Transcriptome of murine testis from wild type mice and mice lacking telomerase for three generations (G3-Terc), Ku86 or both telomerase and Ku86. Keywords: ordered
Project description:Critically short telomeres activate p53-mediated apoptosis, resulting in organ failure and causing malignant transformation. Mutations in genes responsible for telomere maintenance are linked to a number of specific human diseases. We derived induced pluripotent stem cells (iPSCs) from patients with mutations in the TERT and TERC telomerase genes. Telomerase-mutant iPSCs elongated telomeres, but at a lower rate than healthy iPSCs, and the magnitude of the elongation deficit correlated with the specific mutation’s impact on telomerase activity. However, elongation significantly varied among iPSC clones harboring the same mutation, and was affected by genetic and environmental factors. iPSCs cultured in hypoxia showed increased telomere length. Potential influence of residual expression of reprogramming factors on telomerase regulation and telomere length was ruled out by excising the transgenes after successful reprogramming. Evidence for telomerase-independent telomere elongation was not observed in these cells. We demonstrate that telomerase is required for telomere elongation in iPSCs and uncover heterogeneity in telomere maintenance even between clones derived from individual patients or siblings with the same mutation, indicating that telomere phenotype may be influenced by acquired and environmental agents. Our data underscore the necessity of studying multiple clones when using iPSCs to model disease. The exon array were done to validate the pluripotent phenotype of the derived normal and telomerase mutant iPSC and to potentially identify differentially expressed genes in mutant iPSC. Objective: confirming pluripotency by comparing telomerase mutated-, control-iPSC to human ESC and to their parental somatic cells (fibroblast used for iPSC derivation) 20 samples total, 5 different fibroblast cells, 13 iPSC lines, 1 ES line (H1) from different passages
Project description:Critically short telomeres activate p53-mediated apoptosis, resulting in organ failure and causing malignant transformation. Mutations in genes responsible for telomere maintenance are linked to a number of specific human diseases. We derived induced pluripotent stem cells (iPSCs) from patients with mutations in the TERT and TERC telomerase genes. Telomerase-mutant iPSCs elongated telomeres, but at a lower rate than healthy iPSCs, and the magnitude of the elongation deficit correlated with the specific mutation’s impact on telomerase activity. However, elongation significantly varied among iPSC clones harboring the same mutation, and was affected by genetic and environmental factors. iPSCs cultured in hypoxia showed increased telomere length. Potential influence of residual expression of reprogramming factors on telomerase regulation and telomere length was ruled out by excising the transgenes after successful reprogramming. Evidence for telomerase-independent telomere elongation was not observed in these cells. We demonstrate that telomerase is required for telomere elongation in iPSCs and uncover heterogeneity in telomere maintenance even between clones derived from individual patients or siblings with the same mutation, indicating that telomere phenotype may be influenced by acquired and environmental agents. Our data underscore the necessity of studying multiple clones when using iPSCs to model disease. The exon array were done to validate the pluripotent phenotype of the derived normal and telomerase mutant iPSC and to potentially identify differentially expressed genes in mutant iPSC. Objective: confirming pluripotency by comparing telomerase mutated-, control-iPSC to human ESC and to their parental somatic cells (fibroblast used for iPSC derivation)
Project description:Unlike human hearts, zebrafish hearts efficiently regenerate after injury. Regeneration is driven by the strong proliferation response of its cardiomyocytes to injury. In this study, we show that active telomerase is required for cardiomyocyte proliferation and full organ recovery, supporting the potential of telomerase therapy as a means of stimulating cell proliferation upon myocardial infarction. Heart transcriptomes of WT and telomerase defective adult zebrafish animals were profiled by RNASeq, in control conditions and 3 days after heart cryoinjury.
Project description:Telomere homeostasis, crucial for various biological processes, relies on telomerase activity. We identified ZC3H15 as a novel telomerase-interacting protein. Its deletion unexpectedly increased telomerase activity but led to shortened telomeres and cellular senescence. ZC3H15 interacts with telomerase and itself, regulating telomerase activity in an RNA-dependent manner. Proximity labeling showed ZC3H15's interaction with proteins involved in organelle assembly and RNA processes. Loss of ZC3H15 sequestered TERC in the Cajal body, reducing telomerase recruitment to telomeres during S phase. These findings unveil ZC3H15's role in telomere dynamics and cellular senescence, suggesting its potential as a target for cancer therapy or anti-aging interventions.
Project description:Unlike human hearts, zebrafish hearts efficiently regenerate after injury. Regeneration is driven by the strong proliferation response of its cardiomyocytes to injury. In this study, we show that active telomerase is required for cardiomyocyte proliferation and full organ recovery, supporting the potential of telomerase therapy as a means of stimulating cell proliferation upon myocardial infarction.
Project description:Mutant template human telomerase RNAs (MT-hTers) have been shown to induce apoptosis in various cancer cells with high telomerase activity. However, the mechanism by which MT-hTers inhibit growth of cancer cells and their effects on normal cells remain unknown. To determine the effects of MT-hTers on normal cells, MT-hTer-47A and -AU5 were introduced into IMR90 lung fibroblasts that have low telomerase levels. Growth of IMR90 cells following MT-hTers infection was not significantly impaired; however, similar treatments in telomerase-overexpressing IMR90 (IMR90 WThTERT) cells inhibited cell proliferation and induced apoptosis. Confocal microscopy showed that MT-hTers induced DNA damage foci i.e. 53BP1 and γ-H2AX in IMR90 WThTERT cells. Microarray analysis revealed that GADD45γ was significantly elevated in MT-hTers treated IMR90 WThTERT cells. MT-hTers also induced ATM phosphorylation at Ser 1981 in IMR90 WThTERT cells, and Western blot analysis revealed high levels of phosphorylated p53 following down-regulation of cellular TRF2 expression in MT-hTers treated IMR90 WThTERT cells. Taken together, we have elucidated that MT-hTers induce double-stranded DNA breaks (DSBs)-like damages in telomerase-positive IMR90 WThTERT cells following phosphorylation of ATM and p53 via suppression of TRF2 which eventually may have led to apoptosis via elevation of GADD45γ.
Project description:Telomerase reverse transcriptase (TERT) and the noncoding telomerase RNA (TR) subunit constitute the core of telomerase. We now report that the putative F-box protein Pof8 is also a constitutive component of active telomerase in fission yeast. Pof8 functions in a hierarchical assembly pathway by promoting the binding of the Lsm2-8 complex to telomerase RNA, which in turn promotes binding of the catalytic subunit. Loss of Pof8 reduces TER1 stability, causes a severe assembly defect and results in critically short telomeres. Structure profile searches identified similarities between Pof8 and telomerase subunits from ciliated protozoa, making Pof8 next to TERT the most widely conserved telomerase subunits identified to date.