title: Molecular cloning and characterization of the Amylose-Extender gene encoding starch branching enzyme IIB in maize.
abstract: The amylose-extender (Ae) gene encoding starch-branching enzyme IIb (SBEIIb) in maize is predominantly expressed in endosperm and embryos during kernel development. A maize genomic DNA fragment (-2964 to +20,485) containing the Ae gene was isolated and sequenced. The maize Ae mRNA is derived from 22 exons distributed over 16,914 bp. Twenty-one introns, differing in length from 76 bp to 4020 bp, all have conserved junction sequences (GT..AG). Sequence analysis of the 5'- and 3'-flanking regions revealed a consensus TATA-box sequence located 28 bp upstream of the transcription initiation site as determined by primer extension analysis, and a putative polyadenylation signal observed 29 bp upstream of the polyadenylation site based on cDNA sequence. Genomic Southern blot analysis suggests that a single Ae gene is present in the maize genome. Promoter activity was confirmed by testing a transcriptional fusion of the Ae 5'-flanking region between -2964 and +100 to a luciferase reporter gene in a transient expression assay using maize endosperm suspension cultured cells. 5' deletion analysis revealed that the 111 bp region from -160 to -50 is essential for high-level promoter activity.
authors.affiliation: Intercollege Graduate Program in Plant Physiology, The Biotechnology Institute, and Department of Horticulture, The Pennsylvania State University, University Park 16802, USA.
authors.forename: K N
authors.initials: KN
authors.lastname: Kim
authors.forename: D K
authors.initials: DK
authors.lastname: Fisher
authors.forename: M
authors.initials: M
authors.lastname: Gao
authors.forename: M J
authors.initials: MJ
authors.lastname: Guiltinan
mesh_terms: D015061:1,4-alpha-Glucan Branching Enzyme / Q000096:biosynthesis / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D017124:Conserved Sequence; D005091:Exons; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D007438:Introns; D008156:Luciferases / Q000096:biosynthesis / Q000235:genetics; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D015183:Restriction Mapping; D012639:Seeds / Q000201:enzymology; D003313:Zea mays / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development
chemical_list: D011993:Recombinant Fusion Proteins; D008156:Luciferases; D015061:1,4-alpha-Glucan Branching Enzyme; C116400:starch-branching enzyme IIb