Fig. 2

Mettl14 deficiency led to progressive death of rod cells and mislocalization of OS proteins. A, B H&E staining of paraffin sections of RKO and corresponding control retinas at the ages of 3.5 (A) and 5 months (B). Scale bar: 25 μm. The lower panel shows the quantitative analysis of the ONL thickness of the Ctrl (n = 8) and RKO (n = 6) retinas from mice at different ages. Two-way ANOVA was used for statistical analysis, followed by Tukey’s post hoc test. C Representative transmission electron microscopy (TEM) images of photoreceptor outer segments in 3.5-month-old control and RKO mice. Scale bar: 5 μm. Severely disorganized outer segment discs were observed in RKO photoreceptor cells. Arrowheads indicate the outer segments, and enlarged images of outer segment discs are shown in the right panel. Scale bars: 1 μm. D, E Retinal cryosections from 3.5-month-old mice were labeled with rhodopsin, PRPH2 and the IS marker Na–K ATPase (red). DAPI was used to counterstain the nuclei. Scale bars, 25 μm. The white arrowheads indicate mislocalized OS proteins in the IS. Inset images show a cropped and zoomed image. Scale bars, 1 μm. F Representative immunofluorescence images of PDE6B (green) and CNGA1 (red) in retinas from 3.5-month-old Ctrl and RKO mice. Nuclei were counterstained with DAPI (blue). Scale bars, 25 μm. The white arrowheads indicate mislocalized OS proteins in the IS. Inset images show a cropped and zoomed image. Scale bars, 1 μm. OS, outer segment; IS, inner segment; ONL, outer nuclear layer; INL, inner nuclear layer; GCL, ganglion cell layer; RPE, retinal pigment epithelium. *p < 0.05; **p < 0.01; ***p < 0.001. #, no significant difference. Data are presented as the mean ± SEM