Submitted to: Maize Genetics Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 3/13/2003
Publication Date: 3/13/2003
Citation: JIA, H., SANGTONG, V., NETTLETON, D., SCOTT, M.P. EXPRESSION ANALYSIS OF GLU-1DX5 TRANSGENIC CORN. MAIZE GENETICS CONFERENCE ABSTRACTS. 2003. http://www.maizegdb.org/cgi-bin/displayrefrecord.cgi?id=885089.
Technical Abstract: Maize endosperm is one of the most significant agronomic tissues because it is the major component of feed made from maize grain. An important trait of endosperm is therefore its content of essential amino acids. Because the majority of endosperm protein is in the form of seed storage proteins, the seed storage proteins have a large impact on the amino acid content of the seed. The main storage proteins in maize endosperm are the zein proteins, which are encoded by large gene families. We set out to manipulate seed protein content by introducing a gene from wheat called Glu-1Dx5 into transgenic corn plants. This gene encodes a seed storage protein called high molecular weight glutenin. We observed differences in nitrogen content between transgenic kernels and non-transgenic kernels from the same ear. To characterize this difference in greater detail, the levels of the Glu-1Dx5 protein and the zeins in transgenic endosperms were quantified by HPLC. A peak of Glu-1Dx5 that reacts with a Glu1Dx5 antibody can be observed in transgenic plants. Through this quantification, we found that the levels of several zeins were altered in the seeds expressing the Glu-1Dx5 transgene. In order to identify differences in transcript levels, a cDNA microarray was used to study the differences in expression patterns of 8064 selected genes between transgenic and non-transgenic endosperms generated on the same ear. Two zein genes with statistically significant differences in transcript levels were identified. Interestingly, the Glu-1Dx5 promoter region contains a G-box like motif that could possibly serve as the binding site for the maize transcription factor Opaque2. We have produced F2 seed of a cross between o2 and Glu1-Dx5 lines. It will be interesting to see the effect of o2 on transgene expression.