Figure 4.

(A) Dicer1 protein levels in mouse skin as a function of UVB exposure and time. A significant increase in Dicer1 expression was observed after 5 weeks of UVB irradiation. No differences between treatment groups were observed at weeks 10 and 15. Dicer levels did not significantly change with time in control samples, but significantly decreased with time in the UVB group (p < 0.01). (B) MiRNA expression profiling was performed on week-15 samples by nanoString analysis. All miRNAs with ≥2.25-fold change in expression are shown. Of the top six miRNAs differentially expressed, three were within the miR-34 family. (C) miR-34 family expression at week 15 was validated by quantitative reverse transcription polymerase chain reaction. Significant increases in miR-34c, miR-34b-5p, and miR-34b-3p were observed after chronic exposure to UVB. *p < 0.05, **p < 0.01. Color images are available online.