FIG. 4.

Atr1 localization and boron efflux function. (A) Atr1 localizes to the cell membrane and vacuole. The ATR1 gene was tagged with GFP at the C terminus, and cells expressing the Atr1-GFP fusion protein were photographed with a confocal fluorescence microscope. (B) Western blot analysis of the Atr1-GFP fusion protein with anti-GFP antibody showing a single band. (C) Intracellular boron levels in wild-type and atr1Δ cells that were exposed to 50 mM boric acid for 1 h. The cells were transformed with either empty vector or an ATR1 overexpression plasmid (p426-ATR1). Boron levels were normalized to protein levels. The error bars represent three separate measurements.