Evolutionally conserved plant homologue of the Bax Inhibitor‐1 (BI‐1) gene capable of suppressing Bax‐induced cell death in yeast1

The plant homologue of Bax Inhibitor-1, a gene described to suppress the cell death induced by Bax gene expression in yeast, was isolated from Oryza sativa L. (rice) and Arabidopsis. The amino acid sequence of the predicted protein was well conserved in both animal and plant (45% in amino acids) and contained six or seven membrane-spanning segments. Northern blot analysis showed that OsBI-1 transcripts were present in all tissues examined. The OsBI-1 cDNA suppressed cell death induced by mammalian Bax in yeast, suggesting functional conservation of this BI-1 homologue in the plant kingdom.