1-Deoxy-D-Xylulose 5-Phosphate Synthase (DXS) and Its Encoding Genes

Abstract: Terpenoids， also known as isoprenoids， are a class of natural products widely present in various organisms and play key roles in life. Terpenoids are biosynthesized from mevalonate (MVA) or 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway， as found in archaebacteria， fungi， animals and human for the former pathway and in most eubacteria， commonly referred as bacteria， for the latter one. Both pathways exist in plants but locate in cytosol and plastids， respectively. 1-deoxy-D-xylulose 5-phosphate synthase (DXS) is the first and key regulatory enzyme for MEP pathway. The importance of DXS in MEP pathway as well as structure， sub-cellular localization， enzyme activity analysis of DXS protein and DXS genes and mutants were reviewed. Arabidopsis T-DNA mutant cla1-1 with disrupted DXS displays albino phenotype. Accumulation of terpenoids including carotenoids was well correlated with DXS mRNA abundance， and the accumulation can be promoted by overexpressing DXS in transgenic organisms. Typical plastid transit peptide sequence， responsible for plastid localization of the protein， was observed in plant DXS. Various techniques were established for enzyme activity analysis of DXS， which contribute to development and screening of DXS inhibitors. DXS was encoded by a single gene or a small gene family， variable among species. Plant DXS can be sorted into two classes based on homology analysis of protein sequences. Differential expression patterns were observed for DXS members， and generally one of them were widely expressed in various tissues.

CSTR: 32200.14.cjcb.2007.05.0017