The study, published in Nature, showed how the winding and unwinding of 't-loops' at the end of telomeres prevents chromosomes from being recognised as DNA damage. The study also uncovered how this process is regulated.
A significant challenge for maintaining linear chromosomes is that the DNA end must be prevented from being detected as DNA damage. This problem is solved by telomeres, specialised structures of non-coding DNA that protect the end of chromosomes. One way that telomeres are thought to protect the end of the chromosome is by adopting a lasso-like t-loop structure, which acts to bury the DNA end within the telomere and mask it from being detected as DNA damage. These loops are formed by the telomeres folding back on themselves at the end of the chromosome and can be wound or unwound.
Telomeres - Role - DNA - Cells - Cloud
"While telomeres are known to play a vital role in protecting DNA and allowing cells to divide, there has been a cloud of uncertainty surrounding t-loops, their function and importance. This is a question we wanted to resolve with this study," says Panagiotis Kotsantis, paper author and postdoc in the DNA Double Strand Breaks Repair Metabolism Laboratory at the Crick.
The study discovered how important it is for these t-loops to be wound or unwound at the correct stage of the cell cycle.
DNA - Replication - T-loop - Problem - Replication
If DNA replication occurs while the t-loop remains wound up, this creates a problem as the advancing replication fork collides with the t-loop, triggering catastrophic loss of the telomere and damage to the chromosome...
Wake Up To Breaking News!