Fig. 1: Partial reprogramming of murine cells leads to a less proliferative and more de-differentiated cell population.

a Structure of lentiviral vector used to reprogram cells. Cells were infected with M2mCherry vector plus an expression vector carrying murine Oct4, Klf4 and Sox2 under the control of a tetracycline-responsible element (TRE) and blasticidin-resistant gene. Cells not induced with doxycycline but expressing both vectors were used as a control. b Schematic representation of partial reprogramming method. After infection, cells were treated with doxycycline and selected with blasticidin at day 3. Medium without doxycycline was used for control cells during all experiments. c Representative images of morphological changes during partial reprogramming. Scale bars represent 10 μm. d Real-Time qPCR analysis for stemness markers Sox2 and Ssea-1, as well as for melanocytic lineage differentiation markers Mitf and Pmel, for C790 and 4434 at day 20 of reprogramming. Data were normalised using control cells (“− dox”) as reference and Gapdh as housekeeping gene. e Cell proliferation measured by EdU incorporation. Proliferation was analysed at different time points over partial reprogramming as indicated. After incubation with EdU cells were analysed by flow cytometry. Percentage of EdU-positive cells is shown. f Representative images of fluorescence microscopy for cell invasion assay in C790 and 4434 cells. Scale bars represent 500 μm. g Cell invasion assessed by the FluoroBlok invasion assay. Invasion was evaluated at different time points during partial reprogramming. After 20 h incubation, invading cells were labelled and relative fluorescence units were obtained (RFUs = relative fluorescence units). All data are represented as mean ± SEM of three or more independent experiments. Statistical analyses were performed with One-Way ANOVA and post-hoc test; **p < 0.01, ***p < 0.001 and ****p < 0.0001.