RNA instead of telomerase
The natural mechanism of protection against aging and cancer is revealed
Researchers from the Institute of Molecular Biology and the University of Mainz in Germany found out that a type of RNA molecules called TERRA restores telomeres. This mechanism prevents premature aging of cells. The scientists' article was published in the journal Cell (Graf et al., Telomere Length Determines TERRA and R-Loop Regulation through the Cell Cycle). It is briefly described in a press release on the EurekAlert website! (New insight into how telomeres protect cells from premature senescence).
Telomeres are areas at the ends of chromosomes that consist of repeating nucleotide sequences that do not encode protein. When copying DNA, telomeres shorten, and this process is one of the causes of biological aging. When the end sections become too short, the cells stop dividing. However, the same phenomenon acts as a protection against cancer, otherwise malignant cells can multiply indefinitely.
In order to maintain a balance in cells between maintaining telomere length and preventing malignancy (malignancy), there is a finely regulated mechanism. Scientists have found out how shortened ends of chromosomes are recognized and restored in yeast.
It turned out that in the absence of telomerase (an enzyme that restores telomeres), TERRA – non-coding proteins of RNA molecules are attached to shortened telomeres, which trigger reactions to DNA damage (DNA damage response, DDR). RNAs are also adjacent to long telomeres, but they are quickly removed by Rat1 and RNase H2 proteins.
Drawing from an article in Cell – VM
TERRA is present not only in yeast, but also in other organisms, including human. The researchers plan to study the functions of RNA in human cells.
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03.07.2017