title: The Arabidopsis AMP1 gene encodes a putative glutamate carboxypeptidase.
abstract: Arabidopsis amp1 mutants show pleiotropic phenotypes, including altered shoot apical meristems, increased cell proliferation, polycotyly, constitutive photomorphogenesis, early flowering time, increased levels of endogenous cytokinin, and increased cyclin cycD3 expression. We have isolated the AMP1 gene by map-based cloning. The AMP1 cDNA encodes a 706;-amino acid polypeptide with significant similarity to glutamate carboxypeptidases. The AMP1 mRNA was expressed in all tissues examined, with higher expression in roots, stems, inflorescences, and siliques. Microarray analysis identified four mRNA species with altered expression in two alleles of amp1, including upregulation of CYP78A5, which has been shown to mark the shoot apical meristem boundary. The similarity of the AMP1 protein to glutamate carboxypeptidases, and in particular to N-acetyl alpha-linked acidic dipeptidases, suggests that the AMP1 gene product modulates the level of a small signaling molecule that acts to regulate a number of aspects of plant development, in particular the size of the apical meristem.
authors.affiliation: Commonwealth Scientific and Industrial Research Organization, Plant Industry, G.P.O. Box 1600, Canberra, ACT 2601, Australia. chrish@pi.csiro.au
authors.forename: C A
authors.initials: CA
authors.lastname: Helliwell
authors.forename: A N
authors.initials: AN
authors.lastname: Chin-Atkins
authors.forename: I W
authors.initials: IW
authors.lastname: Wilson
authors.forename: R
authors.initials: R
authors.lastname: Chapple
authors.forename: E S
authors.initials: ES
authors.lastname: Dennis
authors.forename: A
authors.initials: A
authors.lastname: Chaudhury
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D002268:Carboxypeptidases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D003583:Cytokinins / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics*; D018519:Meristem / Q000235:genetics / Q000254:growth & development; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D030821:Plants, Genetically Modified; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D029681:Arabidopsis Proteins; D003583:Cytokinins; D018749:RNA, Plant; D002268:Carboxypeptidases; C026134:glutamate carboxypeptidase