Analysis of Globulin-1 promoter activity and the expression of GFP in transgenic maize seed tissues and processing of GFP-containing grain

Abstract

The maize (Zea mays L) kernel is perfectly configured to store proteins and nutrients. The major proteins of the maize kernel are known as seed storage proteins because they have no enzymatic function and they accumulate to a high level for use during germination of the seed as an immediate nutrient source. These seed storage proteins are responsible for much of the nutrient quality of maize when used as a food or feed source. Understanding the regulation of seed storage protein deposition may allow researchers to improve the use of maize grain in a variety of food and feed products, as well as industrial and pharmaceutical applications. To understand the regulation of seed storage proteins and to improve the uses of maize grain, we have created transgenic maize lines that express the reporter gene Green Fluorescent Protein (GFP) under the control of seed storage protein promoters. Therefore, GFP is developmentally and spatially regulated similar to seed storage proteins. Our results indicate that GFP is expressed in seed tissues similar to seed storage proteins. To better utilize grain by dry-milling, we subjected the GFP transgenic grain to a dry-milling process and tracked its recovery. From the results we determined that optimization of dry-milling processes can be accomplished using GFP grain. To better express GFP, and other recombinant proteins in maize kernels, we developed a chimeric promoter that can express GFP in multiple seed tissues. Our results indicate that the chimeric promoter has endosperm and embryo tissue specificity, and that this promoter can be used to express recombinant proteins in maize kernels. To better understand the activity of the Glb1 promoter, we performed experiments that resulted in the correlation of immature leaf activity of the Glb1