Measurement of Short Telomere Load in Individual Cells

Abstract

Increasing evidence demonstrates that shortest more than mean telomere length predicts telomere dysfunction and genomic instability in association with a number of conditions, including cell senescence, aging and tumorigenesis. We developed Universal Single Cell Single Telomere Length Analysis (USC-STELA), based on a PCR-amplification and southern blotting, to measure short telomeres in individual cells. The mean short telomere length measured in individual cells by USC-STELA correlates with that from bulk cells, measured by Universal STELA (U-STELA). The validation and reproducibility of USC-STELA was confirmed using different cell types with known telomere lengths, as well as by using paired sister-cells from human embryos and cultured cells. Interestingly, individual cells known to elongate telomeres via alternative lengthening of telomeres (ALT) have more short telomeres, yet longer mean telomere length than control cells. Moreover, individual senescent fibroblasts carry more short telomeres compared to human embryonic stem cells (hESCs), consistent with the notion that short telomeres contribute to cellular senescence. Additionally, we found a greater load of short telomeres in polar bodies than in matching oocytes, providing further insights into the accelerated polar body DNA degradation following extrusion from the oocyte. USC-STELA provides a new method to study telomere dysfunction in individual cells, with potential to improve our understanding of the role of telomere dynamics in cancer, developmental biology and reproductive medicine.