29 Apr Telomeres Go Beyond Role of Protecting Chromosomes to Impact Gene Expression
The primary function of the telomeres, the random DNA sequences on the ends of chromosomes, is to act as protective caps for the DNA sequences inside the chromosome. Telomeres play an important role in cell replication by sacrificing their DNA in order to preserve the genes inside the chromosomes. However, a recent study led by Jerry W Shay at the University of Texas Southwestern has discovered that telomeres can go beyond their protective role to reach a new level of importance. This is done by reaching and interacting with DNA of adjacent chromosomes. This phenomenon is called DNA looping.
When chromosomes fold inside the nucleus, the telomeres on the ends of these chromosomes come into contact with genes of other chromosomes and alter their expression. Shay and his team studied the gene ISG15 and found that the gene increased even as the telomeres on its own chromosomes shortened.
The team mapped DNA looping in a concentrated region of a chromosome and found that in cells that had longer telomeres, the telomeres interacted with multiple regions of the genome through intricate looping patterns. When they manually manipulated the length of these telomeres, the expression of nearby genes changed again.
The evidence shows that telomere length definitely has an effect on not only genes in their respective chromosomes, but in nearby chromosomes as well via these looping mechanisms. If scientists can discover a way refined way to control the interaction between telomeres and nearby chromosomes, they may be able to control the activation or deactivation of specific genes within the human body.