Poster: Genomic & proteomic resources
Abs #
892: Functional Characterization of Arabidopsis Genes Involved in Pyridoxal Phosphate Metabolism
|
|
Presenter: |
Porter, Charmaine L, portecl@auburn.edu |
Authors | Porter, Charmaine L (A) Bowling, Scott (A) Locy, Robert D (A) | | Affiliations: |
(A): Auburn University
|
|
|
In eukaryotic organisms and certain prokaryotic organisms, a gene family homologous to the Cercospora nicotianae SOR1 gene (yeast SNZ) is a highly conserved protein exhibiting at least 60% homology in Archea, bacteria, and eukaryotes. Despite this conservation, only a minuscule amount of information is known about its function. However, it has been shown in Saccharomyces cerevesiae that SNZ synthesis increases dramatically during stationary phase. SNZ is a paralogous gene family consisting of three members, SNZ1, SNZ2, and SNZ3. In addition, each of these genes is found adjacent to another conserved family named SNO (SNZ- proximal reading frame). Studies show that both SNZ1 and SNO1 are involved in pyridoxine (pyridoxal) biosynthesis, which is the first step of vitamin B-6 production. Vitamin B-6 is an essential nutrient that provides the coenzyme cofactor pyridoxal-5-phosphate (PLP) to most biological systems. Furthermore, it has been documented, recently, that PLP plays a role in protective responses to stress in certain organisms. Using bioinformatic analysis, we have found that the Arabidopsis thaliana genome contains homologues to the SNZ1 and SNO1 genes found in yeast and other fungi. We have used PCR to obtain cDNA clones of the coding sequence of these Arabidopsis genes, and we have obtained single gene deletions of Saccharomyces cerevesiae for the SNO1 and SNZ1 genes. These mutants are unable to grow in media lacking pyridoxine and are more sensitive to singlet oxygen stress because they are unable to make pyridoxine/pyridoxal phosphate. We have expressed the A. thaliana homologues of SNZ1/SNO1 into these yeast deletion mutants, and demonstrated complementation of the phenotype of the SNO1 and SNZ1 growth and biochemical phenotypes.
