Melanogenesis is a biosynthetic pathway for producing of the pigment melanin in human skin. Tyrosinase, a key enzyme, catalyzing is the first step in melanogenesis and the downregulation of the tyrosinase enzyme activity is the most reported method for anti-melanogenesis. According to the hyperpigmentation as an important issue in cosmetic industry, there is a big demand for melanogenesis inhibitors. In the present study, we identified the anti-melanogenic effect of Inonotus Obliquus in α-MSH-induced B16F10 mouse melanoma cells as a new inhibitor. Comparing with control and Inonotus Obliquus extracts treated B16F10, we identified melanin contents, tyrosinase activity, tyrosinase mRNA and protein expression, MITF activity using a constructed plasmid. As shown in these results, we demonstrated that Inonotus Obliquus extracts down-regulated melanin synthesis using down-regulating activity and expression of tyrosinase which is key enzyme to produce melanin. In addition, we revealed expression of tyrosinase is regulated by MITF through repressing MITF transcriptional activity. Inonotus Obliquus extracts has potential to repress melanogenesis and decreased of hyperpigmentation and to use as cosmetic ingredient.

RAD51 is a recombinase that plays a pivotal role in homologous recombination. Although the role of RAD51 in homologous recombination has been extensively studied, it is unclear whether RAD51 can be involved in gene regulation as a co-factor. In this study, we found in silico evidence that RAD51 may contribute to the regulation of genes involved in the autophagy pathway through interaction with E-box proteins such as USF1, USF2, and/or MITF in GM12878, HepG2, K562, and MCF-7 cell lines. The canonical USF binding motif (CACGTG) was significantly identified at RAD51 binding sites in all four cell lines. In addition, genome-wide USF1, USF2, and/or MITF-binding regions significantly coincided with the RAD51-binding sites in the same cell line. Interestingly, the promoters of genes associated with the autophagy pathway were significantly occupied by RAD51 in all four cell lines. Taken together, these results predicted a novel role of RAD51 that had not been addressed previously, and provided evidence that RAD51 could possibly be involved in regulating genes associated with the autophagy pathway, through interaction with E-box binding proteins.