Fachbereich Biologie

Research Associate

Contact:

1997: Dr. rer. nat. (PhD) University of Osnabrück (Prof. Dr. E. Neuhaus)
1997 - 2000: Postdoctoral fellow at the University of Osnabrück (BMELF funded project on lipid metabolism in rapeseed)
since 2000: Research Associate at the University of Kaiserslautern (Plant Physiology)

Major Research Interest:

Nucleotides are uniquely important since they represent building blocks of genetic information (DNA and RNA), represent major energy carriers and are also core elements of cofactors. Nucleotide metabolism is quite complex and can be divided into de novo synthesis, salvage and degradation. Regeneration of nucleotides by the salvage pathway is less energy consuming and takes place at the level of nucelosides and nucleobases. Both metabolites can be transported within plants to distribute these high value intermediates. The members of the protein family of Equilibrative Nucleoside Transporters (ENT) facilitate purine and pyrimidine nucleoside transport.

My first interest is to understand ENT function at the biochemical and physiological level. ENTs are differentially expressed in plants and fulfill distinct physiological functions such as exchange of nucleosides between cells and tissues to balance purines, pyrimidines and nitrogen, influencing seed and pollen germination and putatively interfering with extracellular ATP signaling. Nucleosides imported into a cell may enter the salvage pathway or become subject to degradation. A key enzyme in purine and pyrimidine nucleoside degradation was found to be Nucleoside Hydrolase 1 (NSH1, formerly known as URH1). Plants with either reduced or enhanced NSH1 expression showed germination delays compared to wild-type, pointing to an overall alteration of pyrimidine nucleotide metabolism, since germination is a high-demand time for nucleotides. Further proteins studied are NSH2 and 3 which support NSH1 or act as extracellular, purine-specific nucleoside hydrolase, respectively. Further work concentrates on PYD1, representing the first enzyme in pyrimidine nucleobase degradation.

Selected Recent Publications:

  • Witz S*, Jung B*, Fürst S, Möhlmann T (2012) De novo pyrimidine nucleotide synthesis mainly locates outside of plastids, but a novel nucleobase importer provides substrates for the essential salvage pathway. Plant Cell 24, 1549-1559 *Both authors contributed equally to this paper
  • Cornelius S, Witz S, Rolletschek H, Möhlmann T (2011) Pyrimidine degradation influences germination seedling growth and production of Arabidopsis seeds. J. Exp. Bot. Bot. 62, 5623–5632
  • Bernard C, Traub M, Kunz HH, Hach S, Trentmann O, Möhlmann T (2011) Equilibrative nucleoside transporter 1 (ENT1) is critical for pollen germination and vegetative growth in Arabidopsis. J. Exp. Bot. 62, 4627-37
  • Jung B, Hoffmann C, Möhlmann T (2011) Arabidopsis nucleoside hydrolases involed in intracellular and extracellular degradation of purines. Plant J.65, 703-711
  • Möhlmann T, Bernard C, Hach S, Neuhaus HE (2010) Nucleoside transport and associated metabolism. Plant Biology 12, Supplement 1, 26-32
  • Jung B, Flörchinger M, Kunz HH, Traub M, Wartenberg R, Jeblick W, Neuhaus E, Möhlmann T (2009) Uridine-Ribohydrolase Is a Key Regulator in the Uridine Degradation Pathway of Arabidopsis. Plant Cell 2009 21: 876-891. This work examines Uridine-Ribohydrolase 1 (URH1) expression and function in Arabidopsis, showing biochemical activity on uridine, inosine, and adeonosine. Overexpression and microRNA studies indicate a key role of URH1 in pyrimidine degradation. Highlighted by the science editor of Plant Cell

 

 

 

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