Telomere Length Assay by Southern Blot

For telomere length assay^{39 (link)}, genomic DNA was isolated using genomic DNA purification kit (Promega) and digested with AluI and MboI. Equal amounts of digested DNA (~4 μg) were separated by 0.7% agarose gel electrophoresis in 1× TBE, denatured, and transferred to a GeneScreen Plus membrane (PerkinElmer). The blot was crosslinked, hybridized at 42 °C with 5′-end-labeled ³²P-(TTAGGG)₄ probe in Church buffer, and washed twice for 5 min each with 0.2 M wash buffer (0.2 M Na₂HPO4 pH 7.2, 1 mM EDTA, and 2% SDS) at room temperature and once for 10 min with 0.1 M wash buffer at 42 °C. The images were analyzed by Phosphor-imager, visualized by Typhoon 9410 Imager (GE Healthcare), and processed with ImageQuant 5.2 software (Molecular Dynamics).