Abstract
To investigate the toxic mechanisms of boron, we identified Arabidopsis thaliana genes that confer boric acid tolerance to yeast. Among the identified genes, several putative splicing factors were included. To examine the possible effects of boric acid on the splicing, we performed RT-PCR to detect accumulation of splicing intermediate depending on the boron supply. We found that the splicing of RPL7B was inhibited by high levels of boric acid application. RPL7B is a ribosomal protein and a paralog RPL7A is present in the yeast genome. It was known that disruption of both RPL7A and RPL7B is lethal. Yeast cells with disrupted RPL7A were sensitive to high B whereas those with disrupted RPL7B was not, suggesting that inhibition of splicing of RPL7B is critical in the RPL7A mutant background. The present study is the first demonstration of a molecular mechanism of boron toxicity.
