Abstract
O. brevis bxa1 gene encoding a CPx-ATPase was isolated and characterized in our group. To clarify the gene function for various heavy-metal stresses more detail, several experiments shown below were performed using constructed yeast transformants.
The bxa1 transformant was more sensitive only to Cd stress than a control strain carrying a vector. Fluorescence microscopic observation indicates that Bxa1::GFP fusion proteins localize mainly in endoplasmic reticulum (ER) membrane. Moreover, SEM (scanning electron microscopy) observation suggested that expression of Bxa1 in yeast causes a change of cell size, cell shape and cell viability and that Cd stress causes a promotion of these changes. Protein synthesis related to cell wall and cell membrane formation may be affected by an accumulation of Bxa1 in ER, because ER is an important organ for many protein syntheses in various metabolisms.
