Telomeric noncoding RNA: telomeric repeat-containing RNA in telomere biology

Telomeres are nucleoprotein structures that cap the ends of eukaryoticchromosomes, protecting them from degradation and activation of DNA damageresponse. For this reason, functional telomeres are vital to genome stability. Foryears, telomeres were assumed to be transcriptionally silent, because of theirheterochromatic state. It was only recently shown that, in several organisms,telomeres are transcribed, giving rise to a long noncoding RNA (lncRNA)called telomeric repeat-containing RNA (TERRA). Several lines of evidence nowindicate that TERRA molecules play crucial roles in telomere homeostasis andtelomere functions. Recent studies have shown that the expression and regulationof TERRA are dynamically controlled by each chromosome end. TERRA hasbeen involved in the regulation of telomere length, telomerase activity, andheterochromatin formation at telomeres. The correct regulation of the telomerictranscripts may be essential to genome stability, and altered TERRA levels associatewith tumorigenesis and cellular senescence. Thus, the study of the molecularmechanisms of TERRA biogenesis and function may advance the understandingof telomere-related diseases, including cancer and aging.©2014 John Wiley & Sons,Ltd.