Fig. 8: SP1 regulates METTL1 and WDR4 expression.

a SP1 level was measured in proliferating cells and senescent cells. b Level of METTL1 and WDR4 were quantified in cells with SP1 knockdown or SP1 overexpression. c The presence of SP1 on the METTL1 promoter was evaluated using chromatin immunoprecipitation followed by polymerase chain reaction (ChIP-PCR). d METTL1 promoter activity was assessed by measuring luciferase activity and normalizing it with TK renilla activity. e The binding of SP1 on the METTL1 promoter was evaluated in proliferating and senescent cells using ChIP-PCR. f Protein synthesis was assessed using a puromycin incorporation assay in sp1 depleted cells. Representative result was shown. g Cell proliferating was evaluated by EdU assay in cells that were depleted of SP1. Scale bar = 100 μm. h Senescent cell upon SP1 depletion was evaluated by SA-β-gal staining. Scale bar = 100 μm. i Schematic diagram of model for METTL1 deficiency-induced cell senescence. All the assays were repeated three times. All data were presented as the mean ± SEM. Two-tailed unpaired t test (a, e), one-way ANOVA with Bonferroni’s multiple comparisons test (b–d, g, h). *p  <  0.05, **p  <  0.01, ***p  <  0.001. Source data are provided as a Source Data file.