Abstract
To clarify the biological and biochemical functions of the mitochondrial orf 522 gene from a cytoplasmic male-sterile line of the sunflower, we cloned the entire orf 522 gene inframe into an expression vector (pMAL-c2) of E. coli to obtain a large amount of protein. However, we observed that E. coli harboring a fusion plasmid with the orf 522 gene failed to produce colonies on plates containing 0.3 mM IPTG, an inducer of the p tac promoter of the plasmid. The growth curve of the E. coli also showed that the growth of the cells harboring the fusion plasmid was drastically sup-pressed immediately after the addition of IPTG to the medium. SDS-PAGE and western blots of E. coli lysate showed that a 62 kDa protein was expressed only in the cells with a fusion plasmid after induction with IPTG. These results indicated that the high-level expression of mitochondrial orf 522 gene from the male-sterile sunflower was lethal to E. coli
