Telomere Length Equilibrium Is Maintained by Regulating Access of Telomerase to Telomeres

RNAs play important roles in cells. While much of the focus is on the precise mechanisms of RNA function, less attention has been focused on the importance of the level of specific functional RNAs. The RNA component of telomerase is essential for telomere maintenance. Recent experiments on the telomerase RNA have shown that changes in the level of this functional RNA have major consequences for telomere length regulation. Reduced RNA levels compromise cell viability and cause human disease. Because telomerase RNA is maintained at an equilibrium concentration well below saturation, small changes in RNA concentration can affect enzyme action. The exquisite regulation of this small RNA highlights the role of maintaining the equilibrium concentration of small functional RNAs; tight regulatory balance is likely used to regulate RNAs that play roles in other cellular processes.