Glutamine synthetase (GS) plays a central role in nitrogen metabolism in all plants. GS catalyzes the ATP dependent condensation of ammonia with glutamate (Glu), to yield glutamine (Gln). GS in plants is located either in the cytosol (GS 1) or in the chloroplast (GS 2). A positive correlation between GS/1 activity and yield has been observed in several crop plants, suggesting that GS/1 could represent a key component in nitrogen use efficiency and yield. Thus increasing GS/1 activity by genetic engineering is a viable approach to improve the nitrogen use efficiency in plants. However, there appears to be a wide range of responses to overexpression of GS/1 which appears to be species specific and may depend on the site of nitrogen assimilation in that plant. GS/1 is a very highly regulated enzyme and this regulation may account for the variability in the expression of the transgene. Thus, understanding the regulatory mechanism underlying the expression of GS/1 genes is critical in our strategies to increase GS/1 levels in transgenic plants. Alfalfa transformants with a GS/1 gene driven by a constitutive CaMV 35S promoter showed no increase in GS/1 polypeptide or GS activity. The transcript level for the transgene and the endogenous GS genes also showed a significant drop when the transformants were treated with nitrate. More recent work from our laboratory has shown that the removal of the 3'UTR from the soybean GS/1 transgene abolishes the regulatory constraints in the expression of the transgene in alfalfa and the transformants show increased transgene transcript, polypeptide and enzyme activity. Our hypothesis is that sequences in the 3'UTR of GS genes play a central role in the posttranscriptional regulation of GS/1 gene expression. The goal of this project is to understand the posttranscriptional regulatory mechanism underlying GS/1 expression in plants. The objectives of this proposal are: i. to identify cis-acting elements in GS/1 mRNA with a role in transcript turnover and/or translation initiation; ii. to identify the metabolic signal for this regulatory step; iii. to isolate and characterize the trans-factors that interact with these cis-elements.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Minority Biomedical Research Support - MBRS (S06)
Project #
5S06GM008136-33
Application #
7448498
Study Section
Special Emphasis Panel (ZGM1)
Project Start
Project End
Budget Start
2007-06-01
Budget End
2008-05-31
Support Year
33
Fiscal Year
2007
Total Cost
$315,323
Indirect Cost
Name
New Mexico State University Las Cruces
Department
Type
DUNS #
173851965
City
Las Cruces
State
NM
Country
United States
Zip Code
88003
Pfister, Katherine; Shook, David R; Chang, Chenbei et al. (2016) Molecular model for force production and transmission during vertebrate gastrulation. Development 143:715-27
Edelaar, Pim; Roques, Severine; Hobson, Elizabeth A et al. (2015) Shared genetic diversity across the global invasive range of the monk parakeet suggests a common restricted geographic origin and the possibility of convergent selection. Mol Ecol 24:2164-76
Keyhaninejad, Neda; Curry, Jeanne; Romero, Joslynn et al. (2014) Fruit specific variability in capsaicinoid accumulation and transcription of structural and regulatory genes in Capsicum fruit. Plant Sci 215-216:59-68
Richins, Richard D; Kilcrease, James; Rodgriguez-Uribe, Laura et al. (2014) Carotenoid Extraction and Quantification from Capsicum annuum. Bio Protoc 4:
Unguez, Graciela A (2013) Electric fish: new insights into conserved processes of adult tissue regeneration. J Exp Biol 216:2478-86
Cuaron, Jesus A; Dulal, Santosh; Song, Yang et al. (2013) Tea tree oil-induced transcriptional alterations in Staphylococcus aureus. Phytother Res 27:390-6
Güth, Robert; Pinch, Matthew; Unguez, Graciela A (2013) Mechanisms of muscle gene regulation in the electric organ of Sternopygus macrurus. J Exp Biol 216:2469-77
Guerrero-Ferreira, Ricardo; Gorman, Clayton; Chavez, Alba A et al. (2013) Characterization of the bacterial diversity in Indo-West Pacific loliginid and sepiolid squid light organs. Microb Ecol 65:214-26
Young, Jennifer A; Karmakar, Sukhen; Jacobs, Hollie K et al. (2012) Synthetic approaches to mixed ligand chelators on t-butylphenol-formaldehyde oligomer (PFO) platforms. Tetrahedron 68:10030-10039
Ortega, Jose Luis; Wilson, Olivia L; Sengupta-Gopalan, Champa (2012) The 5' untranslated region of the soybean cytosolic glutamine synthetase ?(1) gene contains prokaryotic translation initiation signals and acts as a translational enhancer in plants. Mol Genet Genomics 287:881-93

Showing the most recent 10 out of 106 publications