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TICK TOCK. “Eukaryotic chromosome termini consist of telomeres, short sequence repeats. According to the telomere hypothesis, DNA replication leads to telomere shortening, resulting in a cellular mitotic clock. Telomerase resets it by telomere synthesis.” https://lnkd.in/dm7mtBZ View in LinkedIn

EVENT COUNTER MINIMA. “An intracellular counting mechanism must be present. These data included: 1) the Phase III Phenomenon itself; 2) our observation that cryogenically preserved cells "remember" at what doubling level they were preserved; and 3) the enormous literature describing hundreds of biological changes occurring in normal cells well before they lose their replicative capacity.” http://protein.bio.msu.ru/biokhimiya/contents/v62/full/62111380.html View in LinkedIn

REPLICOMETER. “The sought-after mechanism should not be called a clock or chronometer because these are devices used for the measurement of the passage of time. Because the replicative limit of normal cells is not directly the result of the passage of time but the number of DNA replications, the putative mechanism should be more properly referred to as an event counter.” http://protein.bio.msu.ru/biokhimiya/contents/v62/full/62111380.html View in LinkedIn

THE CELLULAR COUNTER for age, "the holy grail in cytogerentology. Because cell mortality and immortality are inextricably linked to aging and cancer, the importance of this goal would be difficult to exaggerate.” http://protein.bio.msu.ru/biokhimiya/contents/v62/full/62111380.html View in LinkedIn

IMPERCEPTIBLE AGING. “Animals that do not reach a fixed size in adulthood either do not age or the rate is undetectable. Fascinating recent findings reveal that in the rainbow trout (Oncorhynchus mykiss), an animal with imperceptible age changes, and unlike animals that do age, high telomerase activity has been found in the cells of all of the organs analysed.” https://lnkd.in/esfPTAR View in LinkedIn

APPLICATIONS. “This discovery has profound theoretical and practical implications that include the immortalization of highly differentiated normal human cell types for the production of medically useful proteins.” https://lnkd.in/esfPTAR View in LinkedIn

ENGINEERING IMMORTALITY. “In 1998 it was reported that normal, mortal, human cell strains could be immortalized with apparent retention of their normal properties by transfecting them with vectors encoding the human telomerase catalytic subunit. Thus, the replicometer can be purposefully circumvented. This has provided direct evidence proving the role of telomere shortening in cell senescence and telomerase expression in cell immortality.” https://lnkd.in/esfPTAR View in LinkedIn

INTACT TELOMERES. “Unlike normal mortal cultured cell strains, most immortal cell lines produce telomerase. Thus, the telomeres of most cell lines do not shorten with serial passage in vitro.” https://lnkd.in/esfPTAR View in LinkedIn

CANCER SAMPLES. “Telomerase was later found to occur in extracts of immortal human cell lines and in about 90% of all human tumours studied.” https://lnkd.in/esfPTAR View in LinkedIn

TELOMERE SYNTHESIS. “How do immortal cell lines avoid telomere shortening that, if it occurs, would lead to their demise? They found that telomeres are synthesized de novo by telomerase, a ribonucleoprotein enzyme that extends the 3′ end of telomeres and thus elongates them. It was simultaneously reported that cancer cells have shorter telomeres than do adjacent normal cells.” https://lnkd.in/esfPTAR View in LinkedIn