Researchers at the Institute of Molecular Biology (IMB) and Johannes Gutenberg University Mainz (JGU) have further uncovered the secrets of telomeres, the caps that protect the ends of our chromosomes. They discovered that an RNA molecule called TERRA helps to ensure that very short (or broken) telomeres get fixed again. The work, which was published in the June 29,2017 issue of Cell, provides new insights into cellular processes that regulate cell senescence and survival in aging and cancer. The Cell article is titled “Telomere Length Determines TERRA and R-1 Loop Regulation Through the Cell Cycle.” Telomeres protect the ends of our chromosomes, much like the plastic cap at the end of a shoelace that prevents the lace from unravelling. Over a cell's lifetime, telomeres get gradually shorter with each cell division and therefore the protective cap becomes less and less effective. If the telomeres get too short, it is a signal for the cell that its genetic material is compromised and the cell stops dividing. Telomere shortening and reduced cell division are considered a hallmark of aging and likely contribute to the aging process. However, telomere shortening is also a defense mechanism against cancer because highly proliferative cells can only divide when their telomeres do not shorten. Therefore, telomere shortening is a double-edged sword and has to be carefully regulated to strike a balance between aging and cancer prevention. When a telomere accidentally gets cut short early in a cell's lifetime, it needs to be fixed so that the cell doesn't become senescent too early. "In the life of a cell, you have to find some sort of balance between cancer prevention and aging. Telomeres are at the nexus between the two, so understanding how they are maintained is really important,” said Brian Luke, PhD, Professor at the JGU Institute for Developmental Biology and Neurobiology and Adjunct Director at IMB.
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