title: The y1 gene of maize codes for phytoene synthase.
abstract: The cloned y1 locus of maize was sequenced and found to encode phytoene synthase. Different "wild-type" alleles of the locus were found to differ by the insertion of transposable elements in their promoter and polyA addition regions, and by the length of a CCA tandem repeat series, without any obvious effect on function of the gene. A dominant Y1 ("wild-type") allele was observed to be expressed at highest levels in the seedling but also in the embryo and endosperm. The Mu3 transposable element insertion responsible for a pastel allele of y1, which gives lowered levels of carotenoids in the endosperm of kernels and seedlings grown at high temperatures, was located in the 5' end of the gene. Although the size of the transcript from this y1 mutation suggests that the Mu3 element provides the promoter for this allele, leaf tissue in this mutant line contained approximately normal amounts of y1 mRNA. A recessive allele of y1, which conditions normal levels of carotenoids in the embryo and seedling, but almost no carotenoids in the endosperm, was found to accumulate normal amounts of y1 mRNA in the seedling and embryo, while y1 transcripts were not detected in the endosperm.
authors.affiliation: Division of Science, Northeast Missouri State University, Kirksville 63501, USA. sc12%nemomus@academic.nemostate.edu
authors.forename: B
authors.initials: B
authors.lastname: Buckner
authors.forename: P S
authors.initials: PS
authors.lastname: Miguel
authors.forename: D
authors.initials: D
authors.lastname: Janick-Buckner
authors.forename: J L
authors.initials: JL
authors.lastname: Bennetzen
mesh_terms: D019883:Alkyl and Aryl Transferases; D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D002338:Carotenoids / Q000032:analysis / Q000096:biosynthesis; D003001:Cloning, Molecular; D017931:DNA Primers; D004251:DNA Transposable Elements; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000096:biosynthesis; D012639:Seeds; D017386:Sequence Homology, Amino Acid; D014166:Transferases / Q000096:biosynthesis / Q000235:genetics*; D018911:Trinucleotide Repeats; D003313:Zea mays / Q000201:enzymology* / Q000235:genetics*
chemical_list: D017931:DNA Primers; D004251:DNA Transposable Elements; D011994:Recombinant Proteins; D002338:Carotenoids; D014166:Transferases; D019883:Alkyl and Aryl Transferases; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase