Mechanisms of Gene Regulation
Wilson, Olivia , Ortega, Jose Luis , Sengupta-Gopalan, Champa .
The 5’UTR of a soybean GS1 gene (Gmglnβ1) plays a role in the regulation of its expression.
Glutamine synthetase (GS) plays a central role in nitrogen metabolism in all plants. It catalyzes the ATP dependent condensation of ammonia with glutamate to yield glutamine. Plant GS is an octamer and occurs as a number of isozyme forms and are located either in the cytosol (GS1) or in the chloroplast (GS2). Both GS1 and GS2 are known to be transcriptionally regulated, however, some recent work from our laboratory has shown that a soybean GS1 (GmglnÎ²1) gene is posttranscriptionally regulated at the level of transcript turnover, the process being mediated by its 3’UTR. The main objective of this paper is to determine if the 5’UTR of the GmglnÎ²1 gene plays any role in the regulation of expression of this gene. To accomplish this objective, we have made gene constructs consisting of the GmglnÎ²1 coding region engineered individually with the 3’UTR, the 5’UTR, both the 3’ and 5’UTRs and with no UTRs, all driven by the constitutive CaMV 35S promoter. These gene constructs were agroinfiltrated into tobacco leaves followed by western analysis on the infiltrated tissue to check for the level of accumulation of GS1 protein corresponding to GmglnÎ²1. Our results showed that agroinfiltrated tissues with the gene construct with just the 3’UTR had significantly lower level of accumulation of the transgene protein compared to the tissues infiltrated with the gene construct with both the 5’ and 3’ UTRs. Thus the presence of the 3’UTR in the gene construct downregulated GmglnÎ²1 protein accumulation while the presence of the 5’UTR had an enhancing effect. These results suggest that the 5’UTR and 3’UTR probably function independent of each other to affect gene expression. Experiments are in progress to determine at what level of gene expression does the 5’UTR play a role and if the N/C status has any role in this regulatory step.
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1 - New Mexico State University, Molecular Biology Program, Department of Plant and Environmental Sciences, Skeen Hall: 127N, Corner of College and Knox St., Las Cruces, NM, 88003, United States
2 - New Mexico State University, Department of Plant and Environmental Sciences
3 - New Mexico State University, Department of Molecular Biology and Department of Plant and Environmental Sciences
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM