Tyr expression was decreased by GPNMB-siRNA transfection.

<p>The mRNA (A) or protein (B) expression levels of Tyr and GPNMB in melanocytes PIG1 treated by UVB radiation, GPNMB-siRNA transfection or both of them were determined using real-time quantitative PCR or Western blotting, respectively. The effect of Tyr-siRNA treatment on GPNMB and Tyr expression levels were also determined using real-time quantitative PCR and Western blotting. Data were normalized based on the β-actin levels and were represented as relative expression levels. *p<0.05 by Student's <i>t</i> test when compared with the control group.