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Symbol: Tert Name: Telomerase reverse transcriptase Entrez gene ID: 21752 Ensembl gene ID: ENSMUSG00000021611 Species: Mouse (Taxid: 10090) Functional description: Telomerase is a ribonucleoprotein enzyme essential for the replication of chromosome termini in most eukaryotes. Active in progenitor and cancer cells. Inactive, or very low activity, in normal somatic cells. Catalytic component of the teleromerase holoenzyme complex whose main activity is the elongation of telomeres by acting as a reverse transcriptase that adds simple sequence repeats to chromosome ends by copying a template sequence within the RNA component of the enzyme. Catalyzes the RNA- dependent extension of 3'-chromosomal termini with the 6- nucleotide telomeric repeat unit, 5'-TTAGGG-3'. The catalytic cycle involves primer binding, primer extension and release of product once the template boundary has been reached or nascent product translocation followed by further extension. More active on substrates containing 2 or 3 telomeric repeats. Telomerase activity is regulated by a number of factors including telomerase complex-associated proteins, chaperones and polypeptide modifiers. Modulates Wnt signaling. Plays important roles in aging and antiapoptosis (By similarity). [UniProt] Observation: Overexpression of telomerase results in a high cancer incidence but also a modest mean (10%) and maximum lifespan extension accompanied by a lower incidence of some age-related degenerative diseases, in particular those related to kidney function and germline integrity [15688016]. Mice genetically modified to express telomerase lived 40% longer and do not develop cancer. Overexpression of Tert in mice engineered to be cancer-resistant by means of ehanced expression of p53, p16 and p19ARF (Sp53/Sp16/SARF/TgTERT) decreased telomere shortening with age, delayed aging and increases mean and median longevity by 40% [19013273]. Re-activation of telomerase in a model of premature aging caused by accelerated telomere shortening (duo to telomerase deficiency) was enough to revert some age-associated phenotypes [21113150]. Mice treated with an adeno-assoicated virus vector expressing TERT at the age of one lived 24% longer on average and those treated at the age of two, by 13%. Maximum lifespan of the mice treated at 1 and 2 years was also extended by and 13% and 20%, respectively. AAV9-mTERT treated mice also had improved health, delayed onset of age-related diseases (like osteoporosis and insulin resistance) as well as improved readings in ageing indicators like neuromuscular coordination [22585399]. The gene therapy consists of a single injected via tail vein and achieved a transduction efficiency of 20-50%. Already 1 month after treatment, the treated mice at both age groups had longer telomeres and a decrease in the short telomeres in multiple tissues, while the controls exhibit an increase in short telomerase. In contrast to their control littermates at 3 and 8 months post-treatment the blood of most of the AAV9-treated mice at 1 year had no decrease or exhibit even a net increase in average telomere length and had also no increase or even a marked decrease in percentage of short telomeres with time. Thus, the therapy achieved in perhipheral blood leukocytes a prevention of telomere shortening. Treated mice had lower leves of fasting insulin, improved glucose tolerance and better homeostatic model assessment. Two years old treated mice had higher IGF1 levels. Treated mice at both ages had improved memory scores. AAV9-mTERT treatment increased cyclinD1 positive cells in various tissues. Upon AAV9-mTERT treatment levels of p16 decreased in most organs (with exception of heart). The metabolic and mitochondrial decline in 2 years old mice treated was not as apparent as in controls [22585399]. Interventions: Assays: Organismal Lifespan Classification: References: Aging Relevance Analysis/Source:  GenAge GenDRHomologs Inparanoids Edit \ Update (Admin) | Delete |
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