Disease and Telomerase
Telomerase, the ribonucleoprotein, uses part of itself as a template to tack six-base repeats onto the tips of chromosomes in cells of highly proliferative tissues. Compromised telomerase, then, is likely to affect tissues with high turnover rates. University of California, Berkeley, researchers recently tightened that link (J.R. Mitchell et al., "A telomerase component is defective in the human disease dyskeratosis congenita," Nature, 402:551-5, Dec. 2, 1999). Dyskeratosis congenita, which is passed from carrier mothers to affected sons, affects rapidly dividing epithelium and bone marrow, causing numerous ailments. The disease was identified in 1964, and the molecular defect, in a protein called dyskerin, was discovered in 1998. Dyskerin interacts with telomerase. The researchers found that patients' cells have less telomerase RNA, lower telomerase activity, and shorter telomeres, which causes the chromosomal instability that predisposes to cancer. "If telomeres get too short and the cell escapes proliferative senescence or ...
