Biochemistry

Jay J. Thelen

Associate Professor of Biochemistry

E-mail:thelenj@missouri.edu

Office: 271G Bond Life Sciences Center

Mail: Christopher S. Bond Life Sciences Center
271G Bond Life Sciences Center
University of Missouri
Columbia, MO 65211

Phone: 573-884-1325

Fax: 573-884-9676

Lab: 573-884-5979

Educational background

Curriculum vitae

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Research summary

Most of the ongoing research in my lab is centered on the development of quantitative proteomics approaches and applying these strategies towards seed filling in oilseeds, plants that accumulate oil as the primary storage reserve.

Research description

Plant seeds are an important renewable source of biosynthetic polymers, including protein, starch, oil and fiber. The amount of these biosynthates in harvested seed varies from negligible to a majority of the total mass. Though the biosynthetic pathways for seed storage compounds are mostly known, it is not clear how these pathways are regulated to produce higher quantities of oil versus starch or protein. With recent technological advances in the area of mass spectrometry in conjunction with maturing plant gene databases, high throughput identification of proteins from model and crop plants is technically feasible. Most of the ongoing research in my lab is centered on the development of quantitative proteomics approaches and applying these strategies towards seed filling in oilseeds, plants that accumulate oil as the primary storage reserve. We are using quantitative proteomics data to predict metabolic flow in diverse oilseeds such as castor, canola, soybean and sunflower with particular emphasis on carbon assimilation and intermediary metabolism. I am also interested in the regulation and biochemistry of de novo fatty acid synthesis and triacylglycerol accumulation in oilseeds.

Global protein profiling of oilseeds using two-dimensional gel electrophoresis has revealed multiple isoforms for many metabolic activities. One reason for this could be post-translational modification, most notably protein phosphorylation. It is well known that rate-limiting or branch point enzymes are strategic points for 'fine' control of metabolism by reversible phosphorylation. To investigate this further, members of my lab are also systematically investigating phosphoprotein networks during seed-filling in model and crop oilseeds using advanced proteomics approaches and instrumentation. We use techniques such as Multistage Activation and Electron Transfer Dissociation on an LTQ-XL ETD mass spectrometer to map phosphorylation sites and AQUA peptides for quantification of phosphorylation flux dynamics in response to abiotic and biotic stimuli.

Projects

• Developing tools and strategies for comprehensive, quantitative analysis of plant proteomes
• 2-DE analysis of seed filling in soybean, rapeseed, Arabidopsis and castor
• Quantitative characterization of phosphoproteins expressed during seed development using 2-DE and LC-MS/MS
• Organellar proteomics comparing rapeseed leaf chloroplasts and developing embryo leucoplasts
• Seed oil content protein biomarker discovery using breeding and transgenic germplasm

Selected publications

Houston NL, Hajduch M, Thelen JJ (2009) Quantitative Proteomics of Seed Filling in Castor: Comparison with Soybean and Rapeseed Reveals Differences between Photosynthetic and Non-photosynthetic Seed Metabolism. Plant Physiol. In press

Chen M., Mooney B.P., Hajduch M., Joshi T., Zhou M., Xu D., Thelen J.J. (2009) System analysis of an Arabidopsis mutant altered in de novo fatty acid synthesis reveals diverse changes in seed composition and metabolism. Plant Physiol. 150: 27-41

Jain R., Katavic V., Agrawal G.K., Guzov V.M., Thelen J.J. (2008) Purification and proteomic characterization of plastids from Brassica napus developing embryos. Proteomics 16: 3397-405

Agrawal GK, Hajduch M, Graham, K, Thelen JJ (2008) In-depth investigation of soybean seed-filling proteome and comparison with a parallel study of rapeseed. Plant Physiol. 148: 504-18

Miernyk JA, Thelen JJ (2008) Biochemical approaches for discovering protein-protein interactions. Plant J. 53:597-609

Thelen JJ, Peck SC (2007) Quantitative proteomics in plants: choices in abundance. Plant Cell. 19:3339–46.

Hajduch M, Casteel JE, Tang S, Hearne LB, Knapp S, Thelen JJ (2007) Proteomic analysis of near isogenic sunflower varieties differing in seed oil traits. J. Proteome Res. 6:3232-41

Agrawal GK, Thelen JJ (2006) Large-scale identification and quantitative profiling of phosphoproteins expressed during seed filling in oilseed rape. Mol. Cell. Prot. 5:2044-2059

Kojima M, Casteel J, Miernyk JA, Thelen JJ (2006) The effects of down-regulating expression of Arabidopsis thaliana membrane-associated acyl-CoA binding protein 2 on acyl-lipid composition. Plant Science. 172:36-44

Katavic V, Agrawal GK, Hajduch M, Harris SL, Thelen JJ (2006) Protein and lipid composition analysis of oil bodies from two Brassica napus cultivars. Proteomics. 6: 4586-4598

Mooney BP, Miernyk JA, Greenlief CM, Thelen JJ (2006) Using quantitative proteomics of Arabidopsis roots and leaves to predict metabolic activity. Physiol. Plant. 128:237-250

Hajduch M, Casteel JE, Hurrelmeyer KE, Song Z, Agrawal GK, Thelen JJ (2006) Proteomic analysis of seed filling in Brassica napus: Developmental characterization of metabolic isozymes using high-resolution two-dimensional gel electrophoresis. Plant Physiol. 141:32-46

Employment opportunities

Postdoctoral opportunities

Research areas: Proteomics and phosphoproteomics of seed development and metabolism in oilseeds.

How to apply:

Electronic submission is encouraged, e-mail to thelenj@missouri.edu

Applicants should send CV and names of two references to:
Dr. Jay J. Thelen
Christopher S. Bond Life Sciences Center
271G Bond Life Sciences Center
University of Missouri
Columbia, MO 65211