New research from the University of Maryland (UMD) and the National Institutes of Health reveals a new role for the enzyme telomerase. Telomerase's only known role in normal tissue was to protect certain cells that divide regularly, such as embryonic cells, sperm cells, adult stem cells, and immune cells. Scientists thought telomerase was turned off in all other cells, except in cancerous tumors where it promotes unlimited cell division. The new study found that telomerase reactivates in normal adult cells at a critical point in the aging process. Just before cell death, a burst of telomerase buffers cells from the stresses of aging, slowing the process and reducing DNA damage that could lead to cancer. The study was published in the Proceedings of the National Academy of Sciences on September 2, 2019. The open-access article is titled” Transient Induction of Telomerase Expression Mediates Senescence and Reduces Tumorigenesis in Primary Fibroblasts.” "This study reshapes the current understanding of telomerase's function in normal cells,"said Kan Cao, PhD, senior author of the study and an Associate Professor of Cell Biology and Molecular Genetics at UMD. "Our work shows, for the first time, that there is a role for telomerase in adult cells beyond promoting tumor formation. We can now say that regulated activation of telomerase at a critical point in a cell's life cycle serves an important function." Telomerase prevents the shortening of telomeres--a specialized DNA-protein structure at the end of a cell's chromosomes that protect the chromosomes from damage (shown lighted up in image). Telomerase plays a critical role during embryonic development and stem cell differentiation, when cells divide profusely.
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