Telomeres and telomerase.
Telomeres are the protective DNA-protein complexes found at the ends of eukaryotic chromosomes. Telomeric DNA consists of tandem repeats of a simple, often G-rich, sequence specified by the action of telomerase, and complete replication of telomeric DNA requires telomerase. Telomerase is a specialized cellular ribonucleoprotein reverse transcriptase. By copying a short template sequence within its intrinsic RNA moiety, telomerase synthesizes the telomeric DNA strand running 5' to 3' towards the distal end of the chromosome, thus extending it. Fusion of a telomere, either with another telomere or with a broken DNA end, generally constitutes a catastrophic event for genomic stability. Telomerase acts to prevent such fusions. The molecular consequences of telomere failure, and the molecular contributors to telomere function, with an emphasis on telomerase, are discussed here.
Chan
Simon R W L
SR
University of California, San Francisco, Biochemistry and Biophysics, Box 2200, San Francisco, CA 94143-2200, USA.
Blackburn
Elizabeth H
EH
D004249:DNA Damage / Q000235:genetics; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism*; D019143:Evolution, Molecular; D015723:Gene Library; D008957:Models, Genetic; D009154:Mutation / Q000235:genetics; D012313:RNA / Q000378:metabolism; D019098:Telomerase / Q000378:metabolism*; D016615:Telomere / Q000235:genetics* / Q000378:metabolism
D004268:DNA-Binding Proteins; D012313:RNA; D019098:Telomerase