Expression Analysis of a Germin-Like Protein with Mn-Superoxide Dismutase Activity in a Moss, Barbula unguiculata

Abstract

We isolated a germin-like protein with Mn-SOD activity (BuGLP) from a moss, Barbula unguiculata. Our purpose in this study is to bring out physiological roles of BuGLP based on its SOD activity.
When NaCl was added into the cells the BuGLP mRNA levels increased, but most of BuGLP protein was released into the medium. On the other hand, the addition of methyl viologen or H₂O₂ decreased the BuGLP mRNA levels dose dependently. The addition of H₂O₂ in the presence of NaCl decreased the BuGLP mRNA levels compared with those in the presence of NaCl alone. This treatment caused the release of BuGLP protein into the medium. These results suggest that H₂O₂ generated from superoxide by BuGLP plays an important role in regulation of BuGLP expression. To clarify the mechanisms that cause these regulations, the promoter region of BuGLP gene was cloned.