Measurement of telomere length: A new assay using QuantiGene chemistry on a luminex platform

Abstract

Background: Telomeres are tandem repeats of sequences present at the end of the chromosomes that maintain chromosomal integrity. After repeated cell division, telomeres shorten to a critical level, triggering replicative senescence or apoptosis, which is a key determinant of cellular aging. Short telomeres also contribute to genome instability and are a hallmark of many cancers. There are several methods for estimating telomere length (TL) from extracted DNA samples. Southern blot is accurate but requires a large quantity of DNA and is expensive. qPCR is cost-effective and requires a small quantity of DNA and is therefore widely used for large-scale epidemiologic studies; however, it typically requires triplicates. We describe a novel multiplexed probe-based non-PCR method for TL measurement. Methods: A small amount of DNA (∼50 ng) is hybridized to telomere repeat sequence-specific probes (T) and a reference single gene probes (R). T and R signals are detected from a single reaction well containing the same input DNA. Branching DNA technology is used to amplify the signal, which is detected by Luminex technology. Results: The intra- and interassay CV (∼3% and ∼5%, respectively) shows the precision of the new assay and the measurements from single well correlated well with traditional single-plex qPCR run in triplicate (r = 0.7 to 0.8). The assay was also validated in an independent set of samples using Southern blot (r = 0.74). Conclusion: We describe a novel assay for TL assessment using the Luminex platform. Impact: This may offer an alternative cost-efficient way to study TL in extracted DNA samples.