Abstract
Overexpression of mammalian apoptotic protein Bax induces cell death in plant and in yeast. AtBI-1 (Arabidopsis Bax Inhibitor-1) gene was identified by a functional screening of cDNAs, which rescue yeast from Bax-mediated cell death. By utilizing the AtBI-1 gene controlled under the GAL1 promoter as a cell death suppressor, cdf1 (cell growth defect factor-1) gene was isolated from Arabidopsis cDNA library. It was confirmed that the overexpression of cdf1 arrested yeast cell growth, which was suppressed by AtBI-1. The cdf1 gene encodes an unknown protein of 258 amino acids with a molecular weight of 28.8 kDa. The protein has three transmembrane domains in its C-terminal region. The cdf1 protein fused with GFP was localized in yeast mitochondria, whilst same protein located in plant chloroplasts. Based on these results, possible molecular mechanism of cdf1-induced growth defect will be discussed.
