Poster: Secondary metabolism

Abs # 257: Expression of enzymes in the pantothenate pathway of arabidopsis.

Presenter:	Coxon, Katy M., kc296@cam.ac.uk
Authors	Coxon, Katy M. (A)   Ottenhoff, Harald H. (A)   Whitney, Heather M. (A)   Smith, Alison G. (A)
Affiliations:	(A): University of Cambridge, Plant Sciences
Web Site:	http://www.plantsci.cam.ac.uk

Pantothenate (vitamin B₅)is a water soluble vitamin essential for the synthesis of coenzyme A and acyl carrier protein, cofactors in energy yielding reactions including carbohydrate metabolism and fatty acid synthesis. Pantothenate is synthesized de novo by plants and microorganisms, however, animals require the vitamin in their diet. Utilising our knowledge of the pathway in E. coli, we have discovered and cloned three genes in the Arabidopsis pathway, panB1, panB2 and panC. Work is now being carried out to elucidate expression patterns of the transcripts and proteins encoded by these genes. Through the application of RT-PCR preliminary results suggest panB1 and panB2 are transcribed in two week old Arabidopsis seedlings, and GUS reporter gene studies show expression of panC at the same stage. Western blotting has been used to determine the expression of the proteins in different plant tissues. KPHMT1 (panB1) is seen to be expressed in root tissue of mature Arabidopsis, whilst PS (panC) expression is seen throughout all tissues. Future work includes oxerexpression in E. coli and purification of recombinant Arabidopsis KPHMT1, KPHMT2 and PS to carry out kinetic studies; synthesis of GUS reporter gene constructs of Arabidopsis panB1 and panB2 to further research into their expression; and assay of levels of pantothenate during the life cycle of Arabidopsis.