Validation of telomere invasion and recombination events in C. elegans (2014)

Undergraduates: Yiwen Wu, Megan Brady Shawn Ahmed

Faculty Advisor: Shawn Ahmed
Department: Biology

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After multiple cellular divisions, uncapped, critically shortened telomeres are often healed by end-to-end chromosome fusions, genome rearrangements commonly found in tumors. Previously, breakage-fusion-bridge (BFB) cycles have been the sole model for the generation of chromosome fusions. This study attempts to further validate a telomere repair mechanism in Caenorhabditis elegans, the Fork Stalling and Template Switching model (FoSTeS) that results in shortened, uncapped telomeres invading interstitial telomere sequences followed by promiscuous DNA synthesis. This model may explain the multiple inverted DNA repeats found between fused chromosomes. This method has been applied to the first interstitial telomere sequence (ITS) on the right arm of the X chromosome (XR-1) in telomerase reverse transcriptase deficient mutant strains (trt-1 mutants), as ITS-telomere recombination events indicate fusion and have consistently been found using polymerase chain reaction (PCR) analysis. The results of this study support the FoSTeS model by showing that interstitial telomere sequences on the left arm of the second chromosome also exhibit these recombination events.