Search

Terminal restriction fragment analysis is the only method currently available for measuring telomere length in Caenorhabditis elegans. Its limitations include low sensitivity and interference by the presence of interstitial telomeric sequences in the C.elegans genome. Here we report the adaptation of single telomere length analysis (STELA) to measure the length of telomeric repeats on the left arm of chromosome V in C.elegans. This highly sensitive PCR-based method allows telomere length measurement from as few as a single worm. The application of STELA to eight wild-type C.elegans strains revealed considerable strain-specific differences in telomere length. Within individual strains, short outlying telomeres were observed that were clearly distinct from the bulk telomere length distributions, suggesting that processes other than end-replication losses and telomerase-mediated lengthening may generate telomere length heterogeneity in C.elegans. The utility of this method was further demonstrated by the characterization of telomere shortening in mrt-2 mutants. We conclude that STELA appears to be a valuable tool for studying telomere biology in C.elegans.

Telomerase is essential to maintain telomere length in most eukaryotes. Other functions for telomerase have been proposed but molecular mechanisms remain unclear. We studied Caenorhabditis elegans with a mutation in the trt-1 telomerase reverse transcriptase gene. Mutant animals showed a progressive decrease in brood size and typically failed to reproduce after five generations. Using PCR analysis to measure the length of individual telomere repeat tracks on the left arm of chromosome V we observed that trt-1 mutants lost approximately 125bp of telomeric DNA per generation. Chromosome fusions involving complex recombination reactions were observed in late generations. Strikingly, trt-1 mutant animals displayed a high frequency of telomeres with many fewer repeats than average. Such outlying short telomeres were not observed in mrt-2 mutants displaying progressive telomere loss very similar to trt-1 mutants. We speculate that, apart from maintaining the average telomere length, telomerase is required to prevent or repair sporadic telomere truncations that are unrelated to the typical 'end-replication' problems.