FIG 7.

Loss of TIN2L phosphorylation inhibits progressive telomere elongation in telomerase-positive HT1080 cells. (A) Representative telomere Southern blot analysis of telomere length in kilobase pairs (kb) over time in HT1080 cells overexpressing TIN2S, TIN2S-R282H, TIN2L, TIN2L-S396A, TIN2L-S396E, or GFP control. HT1080 cells overexpressing the indicated TIN2 proteins were collected at various times following induction with lentivirus and blastocidin selection and analyzed by the terminal restriction fragment assay. (B) Quantification of data in panel A using densitometry analysis. Error bars indicate the SDs from two separate terminal restriction fragment assays. (C) Western blot showing TIN2 expression levels in each cell line. Total cell protein lysates were prepared using 2× Laemmli buffer.