Telomerase is anRNAprotein which is anenzyme. It addsDNA sequence repeats ("TTAGGG" in all vertebrates) to the end of DNA strands in thetelomere regions.
The telomeres are disposablebuffers blocking the ends ofeukaryoticchromosomes. They are a region of repeatednucleotides containing noncoding DNA. Telomeres are destroyed duringcell division, and are remade by the enzyme telomerase.[1]
The function of telomeres is to avoid the loss of important DNA from chromosome ends. Every time thechromosome is copied 100–200 meaningless nucleotides are lost, which causes no damage to the organism's DNA. So, the telomeres are shortened after eachreplication cycle, and then are restored to their proper length by telomerase. Telomerases carry their ownRNA molecule, which is used as atemplate to elongate the telomeres.
The existence of a compensatory mechanism (a 'fix') for telomere shortening was first predicted by Soviet biologistAlexey Olovnikov in 1973.[2] He also suggested the telomere hypothesis ofageing and the telomere's connections tocancer.
Telomerase was discovered byCarol Greider andElizabeth Blackburn in 1984 in theciliateTetrahymena.[3] Together withJack Szostak, Greider and Blackburn were awarded the 2009Nobel Prize in Physiology or Medicine for their discovery.[4]