In a recent study entitled “Putative telomere-independent mechanisms of replicative aging reflect inadequate growth conditions” the authors found that the length of telomeres is capable of silencing genes and activating them in different periods of a cell lifetime, and therefore are able to contribute to aging and disease. The study was published in the Genes and Development journal.
Telomeres are specific sequences at the end of the cells’ chromosomes that prevent them from damage and/or from fusion with neighboring chromosomes. Every time a cell divides, telomeres become shorter — a phenomena that was previously reported to be involved in human disease and mortality. While shorter telomeres were associated with aging and diseases, longer telomeres are linked to healthy aging and longevity. However, telomeres’ shortening was also related to activation or repression of genes.
Now, a team of researchers at UT Southwestern Medical Center showed that before telomeres are decreased to a length that compromises the cells, the small decreases can have an impact on the regulation of genes. Specifically, they showed a dynamic regulation of gene expression upon telomere length — a key and novel finding of their study, since a longer telomere can form a loop at the end of the chromosome and putting in contact with the telomere genes, thus enabling telomeres to regulate their expression. On the contrary, shorter telomeres prevent loop formation and as a result no interaction with other genes.
Dr. Jerry W. Shay, Professor and Vice Chairman of Cell Biology at UT Southwestern and one of the senior authors commented, “Our results suggest a potential novel mechanism for how the length of telomeres may silence genes early in life and then contribute to their activation later in life when telomeres are progressively shortened. This is a new way of gene regulation that is controlled by telomere length.”
Dr. Woodring E. Wright, Professor of Cell Biology and Internal Medicine, the other senior author added, “We have developed the concept that telomere shortening could be used as a timing mechanism to respond to physiological changes in very long-lived organisms, such as humans, to optimize fitness in an age-appropriate fashion.”