Fig. 3: Telomerase recruitment is facilitated by known regulators of nuclear F-actin.
From: Nuclear actin and DNA replication stress regulate telomere maintenance by telomerase
a Model of replication stress-induced polymerization of nuclear F-actin, highlighting proteins involved in nuclear actin import, regulation, polymerization, and function. Created in BioRender. Harman, A. (2025) https://BioRender.com/1h81xvg. b, c Representative SABER FISH images of 293T cells probed for hTR (yellow) and telomeres (pink) with DAPI (blue) staining. Cells were treated with DMSO (NTC), 0.2 μM INK128 (mTORi), 200 μM CK-666 (ARP2/3i), 5 μM wiskostatin (WASPi), 10 μM LIMKi-3 (LIMKi), 10 mM BDM (MYHi) or 10 nM BTS (MYHi #2) for 16 h. Cells were subsequently treated with DMSO or 1.5 μM APH for 30 min. d, e Average hTR/telomere co-localizations in 293T cells shown in (b) and (c). Significance above the columns for the inhibitor treated samples - APH is expressed relative to NTC - APH; significance for the inhibitor + APH samples is expressed relative to NTC + APH. f Representative SABER FISH images of 293T cells transfected with control, cofilin 1 (CFL1) or importin 9 (IPO9) siRNA, ± 30 min APH (1.5 μM) treatment. Cells were stained with DAPI (blue) and probed for hTR (yellow) and telomeres (pink). g Western blot of 293T cells transfected with control, CFL1 or IPO9 siRNA, probing for CFL1, IPO9 and actin as a control. h Telomerase presence at telomeres in 293T cells transfected with control, cofilin 1 (CFL1) or importin 9 (IPO9) siRNA, ± 30 min 1.5 μM APH treatment. Significance above the columns for each siRNA treated sample - APH is expressed relative to siControl - APH; siRNA + APH sample significance is expressed relative to siControl + APH. i SABER FISH images of HeLa, A549, HT1080 and HCT116 cells treated with DMSO (NTC) or 0.2 μM INK128 (mTORi) for 16 h, probing for hTR (yellow) and telomeres (pink) with DAPI staining (blue). j Normalized telomerase presence at telomeres from (i). For all microscopy images, scale bar = 2 μm. Co-localizations are indicated by white arrows. Mean and number of nuclei quantified per replicate are listed in Source Data. All bar graphs displayed as mean ± SEM; n = 3 independent biological replicates; One-way ANOVA with Šídák’s multiple comparisons test.
