Tuesday, November 18, 2014

Discovery of a mechanism that controls the fitness of cells has been found.

     Scientists at The UT Southwestern Medical Center uncovered a mechanism that controls the fitness of cells. The cell biologist team say they may be able to explain the aging of cells and how they initiate and transmit diseases by a mechanism involving the end caps of DNA. They discovered that the telomeres form loops that determine whether or not certain genes are turned off when young and are activated later in life. These genes contribute to aging and diseases. 

     Dr. Jerry W, leader of the team, said "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." 

     As known, telomeres cap the ends of the cell's chromosomes to protect them from damage. However, each time the cell divides, the telomeres become shorter and once they reach a certain length, the cell can’t divide anymore. When it can’t divide, it goes into a phase known as “growth-arrest phase” and begins to produce different products than the younger cell produced. The telomere shortening has been shown to influence which genes are active or silent in some diseases.

     The team showed that when a telomere is long, the endcap can form a loop with the chromosome that brings the telomere close to genes once thought of as too far away to be regulated by telomere length. Once the telomere and “new” genes on the same chromosome are close enough to each other, the telomeres switch those genes to be “off.” The team also showed that when telomeres are short, the chromosome does not form a loop. Without this loop, the telomere can decide to turn that target gene on or off.

     Dr. Wright said, "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."

     This new discovery could potentially cure diseases that are due to the aging of cells. If a treatment can be discovered to help promote the looping of these telomeres before they become that critically short length, the possibilities of cures are endless. 

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