title: Identification, characterization and comparative analysis of a novel chorismate mutase gene in Arabidopsis thaliana.
abstract: Phenylalanine, tyrosine, and tryptophan have a dual biosynthetic role in plants; they are required for protein synthesis and are also precursors to a number of aromatic secondary metabolites critical to normal development and stress responses. Whereas much has been learned in recent years about the genetic control of tryptophan biosynthesis in Arabidopsis and other plants, relatively little is known about the genetic regulation of phenylalanine and tyrosine synthesis. We have isolated, characterized and determined the expression of Arabidopsis thaliana genes encoding chorismate mutase, the enzyme catalyzing the first committed step in phenylalanine and tyrosine synthesis. Three independent Arabidopsis chorismate mutase cDNAs were isolated by functional complementation of a Saccharomyces cerevisiae mutation. Two of these cDNAs have been reported independently (Eberhard et al., 1993. FEBS 334, 233-236; Eberhard et al., 1996. Plant J. 10, 815-821), but the third (designated CM-3) represents a novel gene. The different organ-specific expression patterns of these cDNAs, their regulation in response to pathogen infiltration, as well as the different enzymatic characteristics of the proteins they encode are also described. Together, these data suggest that each isoform may play a distinct physiological role in coordinating chorismate mutase activity with developmental and environmental signals.
authors.affiliation: Department of Biochemistry, University of Chicago, Chicago, IL, USA.
authors.forename: E M
authors.initials: EM
authors.lastname: Mobley
authors.forename: B N
authors.initials: BN
authors.lastname: Kunkel
authors.forename: B
authors.initials: B
authors.lastname: Keith
mesh_terms: D000595:Amino Acid Sequence; D000598:Amino Acids, Cyclic / Q000494:pharmacology; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics*; D015152:Blotting, Northern; D002826:Chorismate Mutase / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D005816:Genetic Complementation Test; D007527:Isoenzymes / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D009154:Mutation; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution
chemical_list: D000598:Amino Acids, Cyclic; D018076:DNA, Complementary; D007527:Isoenzymes; D018749:RNA, Plant; D002826:Chorismate Mutase