Electroporated protoplasts express seed specific gene promoters

The soybean 7S seed storage protein, -conglycinin, is comprised of three major subunits, , , and . Chimeric genes having -conglycinin and subunit promoters and the -glucuronidase gene coding sequence were constructed and electroporated into protoplasts prepared from three cultured cell lines and from tobacco mesophyll cells. The -conglycinin promoters were active in all protoplasts examined, and their activities were 10–60% of that of the cauliflower mosaic virus 35S promoter. In electroporated protoplasts isolated from tobacco suspension cultures the time course of expression and the pattern of cell cycle dependency of the -conglycinin promoters were similar to those of the 35S promoter. The responses to exogenously added L-methionine and abscisic acid, which are known to have differential effects on the expression of -conglycinin promoters in cultured soybean cotyledons, were essentially the same among the promoters used. The results indicate that -conglycinin promoters are expressed in electroporated protoplasts, but their regulation is relaxed. Current Address: Department of Botany, Faculty of Science, University of Tokyo, Hongo, Tokyo 113, Japan