A team of researchers discovered that telomeres, the repeated DNA-protein complexes at the end of chromosomes that prevent chromosomes from fraying, also contain RNA.
Telomeres progressively shorten every time a cell divides. After a cell has grown and divided a few dozen times, the telomeres prevent further division. If they don’t function right, cells either end up with damaged chromosomes or they become immortal and continue dividing endlessly.
It was thought that telomeres’ DNA was not transcribed into strands of RNA. In the current study, however, the research group discovered telomeric repeat containing RNA (TERRA) and that these TERRA molecules were transcribed from mammalian telomeres.
The team also discovered that the RNA in the telomere is regulated by a protein in the telomerase enzyme, which rebuilds the telomere so that the cells can keep dividing. Previous studies suggest that the telomerase enzyme keeps rebuilding telomeres long past the cell’s normal lifetime, which causes tumors in roughly 90% of human cancers.
The research was performed by the Swiss Institute for Experimental Cancer Research in collaboration with the University of Pavia. It was published online in the October 4 issue of Science Express.