FIGURE 4.

Expression of shelterin subunits in hTERT-immortalized cell lines of control, LMNA mutant andWRN mutant fibroblasts. (A) Western analysis of TRF2, TRF1, POT1, TIN2, hRap1, and TPP1 in hTERT-immortalized fibroblasts of indicated cell lines. Autoradiographies with higher exposures are shown for clarification of bands. (B) Analysis of relative telomere lengths expressed as average telomere intensities ± s.d. in indicated cell types, as shown in Figure 1. A minimum of 70 cells were analyzed for each cell lines. Relative mean telomere lengths (±s.d.) were measured in hTERT-immortalized fibroblasts using qPCR. (C) TRF2 mRNA expression in hTERT-immortalized normal, LMNA mutant and WRN mutant fibroblasts. TRF2 mRNA expression was detected by qRT-PCR. GAPDH mRNA was used as an internal standard. Data are presented as mean ± s.d. from three independent experiments. The control (82-6) value was taken as onefold. (D) Expression of TRF2 protein after proteasome inhibition in LMNA mutant cells. hTERT-immortalized cell lines of control and LMNA mutant fibroblasts were incubated in the presence or absence of MG-132 for 6 h and TRF2 protein levels were detected using immunoblotting.