The role of KLF4 in melanogenesis and homeostasis in sheep melanocytes

KLF4 expression has been associated with hair color in mammals and has also been found to regulate melanoma cell growth. Here, we assessed the influence of KLF4 on coat color formation and melanocytes. We found that KLF4 was highly expressed in the black skin of sheep both at the mRNA and protein levels compared with white skin. KLF4 immunostaining further showed that KLF4 protein was mainly expressed in epidermal, outer root, and hair bulb regions. In sheep melanocytes, the proliferation of melanocytes was inhibited by KLF4 overexpression and this decrease in cell proliferation was coupled with induction of the S phase, cell cycle arrest, and apoptosis. In vitro cell migration assays showed that KLF4 suppressed cell migration. In addition, KLF4 overexpression significantly increased melanin production and pigment-related gene expression. Collectively, our findings show that KLF4 is important for coat color formation and melanocyte homeostasis.