How Telomeres Solve the End-Protection Problem
Titia de Lange
The ends of eukaryotic chromosomes have the potential to be
mistaken for damaged or broken DNA and must therefore be protected
from cellular DNA damage response pathways. Otherwise, cells
might permanently arrest in the cell cycle, and attempts to
"repair" the chromosome ends would have devastating consequences
for genome integrity. This end-protection problem is solved
by protein-DNA complexes called telomeres. Studies of mammalian
cells have recently uncovered the mechanism by which telomeres
disguise the chromosome ends. Comparison to unicellular eukaryotes
reveals key differences in the DNA damage response systems that
inadvertently threaten chromosome ends. Telomeres appear to
be tailored to these variations, explaining their variable structure
and composition.
