Fig 2: Cells harboring the mutants fail to undergo morphological differentiation. (A) Cells harboring the wild type (WT) or POLR3B (R550X) were allowed to differentiate for 5 days. Some cells in the bottom images are surrounded by white dotted lines (a and b). The square fields a and b indicated by the dotted lines in the bottom panels are magnified in the upper panels a and b. Images of cells at 0 day are also shown. (B) Cells with widespread membranes were statistically assessed (** p < 0.01; n = 5 fields (50 cells in total)). (C) The lysates of the respective cells were immunoblotted with an antibody against PLP1 and CNPase, cell lineage marker Sox10, and control actin. (D) Their expression levels are shown and statistically compared to their respective controls. (* p < 0.05 of Student’s t-test; n = 3 blots).

Fig 3: Ibuprofen improves phenotypes in cells harboring the mutants. (A) Cells harboring POLR3B (R550X) were allowed to differentiate in the presence or absence of ibuprofen for 5 days. Some cells in the upper images are surrounded by white dotted lines. The square fields indicated by the dotted lines in the upper panels are magnified in the respective lower panels. (B) Cells with widespread membranes were statistically assessed (** p < 0.01; n = 5 fields (50 cells in total)). (C) The lysates of the respective cells were immunoblotted with an antibody against PLP1, CNPase, Sox10, and actin. (D) Their expression levels are shown statistically compared to their respective controls (** p < 0.01; n = 3 blots).

Fig 4: Ibuprofen does not have significant effects on phenotypes in cells harboring the wild type POLR3B. (A) Cells harboring the wild type were allowed to differentiate in the presence or absence of ibuprofen for 5 days. Some cells in the upper images are surrounded by white dotted lines. The square fields indicated by the dotted lines in the upper panels are magnified in the respective lower panels. (B) Cells with widespread membranes were statistically assessed (n = 5 fields (50 cells in total)). (C) The lysates of the respective cells were immunoblotted with an antibody against PLP1, CNPase, Sox10, and actin. (D) Their expression levels are shown statistically compared to their respective controls (n = 3 blots).