Kallikrein isoforms expressed in skin and GATA3

Abstract

Skin is a stiff barrier from the outer environment but, at the same time, desquamation occurs easily in relation not only to constant skin turnover but also to injuries. For desquamation, serine‐proteases/inhibitors balance is important. Among kallikrein families (KLKs), KLK5 and KLK7 are considered to play main role as serine‐proteases. However, when the gene expression level was compared, we found that KLK1 and KLK11 mRNAs were more abundant than KLK5 and KLK7 mRNAs in skin. Therefore, KLK1 promoter was cloned into Luciferase vector to clarify the mechanism of high KLK1 expression. When −957/+36 from the major transcriptional site was transfected, the highest intensity was observed but decreased by −957/−879 depletion. DNA footprinting using nuclear extract from cultured epidermal cell, NHEK, showed the sequence around −924 where GATAs binding site located was protected. RT‐PCR proved that only GATA3 expressed in skin and EMSA using anti‐GATA3 antibody succeeded to supershift the −924 oligonucleotides/nuclear protein complex. Moreover, introduction of GATA3 expression vector to fibroblast succeeded to activate KLK1 promoter and, on the contrary, introduction of GATA3 dominant negative expression vector to NHEK inhibited its activity. Thus, GATA3, which was found to be important for T cell lineage at first, was proved to be one of the major expression regulaters of KLK1 in skin.