Identification of cis-acting elements important for expression of the starch-branching enzyme I gene in maize endosperm

• Published in: Plant physiology (Bethesda) 1999-09, Vol.121 (1), p.225-236
• Main Authors: Kim, K.N, Guiltinan, M.J
• Format: Article
• Language: English
• Subjects: 1,4-alpha-Glucan Branching Enzyme - genetics; Agronomy. Soil science and plant productions; Base Sequence; Basic-Leucine Zipper Transcription Factors; beta-glucuronidase; binding; Binding, Competitive; Biological and medical sciences; BIOLOGICAL PATHWAYS; BIOLOGY AND MEDICINE, BASIC STUDIES; Carbohydrates - pharmacology; cell suspension culture; Cells, Cultured; Corn; DNA - genetics; DNA - metabolism; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Economic plant physiology; electrophoresis; ENDOSPERM; ENZYMES; exons; Exons - genetics; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation, Plant - drug effects; GENE REGULATION; Genes; Genes, Plant - genetics; genetic regulation; hexosyltransferases; Introns; Introns - genetics; luciferase; MAIZE; Metabolism; Molecular and cellular biology; Molecular genetics; Molecular Genetics and Genomics; Molecular Sequence Data; Mutation; Net assimilation, photosynthesis, carbon metabolism. Photorespiration, respiration, fermentation (anoxia, hypoxia); Nutrition. Photosynthesis. Respiration. Metabolism; Photosynthesis, respiration. Anabolism, catabolism; Plant physiology and development; Plant Proteins - genetics; Plant Proteins - metabolism; Plasmids; Promoter regions; Promoter Regions, Genetic - genetics; reporter genes; Repressor Proteins - genetics; Repressor Proteins - metabolism; Response Elements - genetics; seed development; STARCH; Starches; Sugars; TRANSCRIPTION; transcription (genetics); transcription factors; Transcription Factors - genetics; Transcription Factors - metabolism; Transcription, Genetic - genetics; Transcription. Transcription factor. Splicing. Rna processing; transgenic plants; Zea mays; Zea mays - cytology; Zea mays - drug effects; Zea mays - enzymology; Zea mays - genetics
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.121.1.225

The genes encoding the starch-branching enzymes (SBE) SBEI, SBEIIa, and SBEIIb in maize (Zea mays) are differentially regulated in tissue specificity and during kernel development. To gain insight into the regulatory mechanisms controlling their expression, we analyzed the 5'-flanking sequences of Sbe1 using a transient gene expression system. Although the 2.2-kb 5'-flanking sequence between -2,190 and +27 relative to the transcription initiation site was sufficient to promote transcription, the addition of the transcribed region between +28 and +228 containing the first exon and intron resulted in high-level expression in suspension-cultured maize endosperm cells. A series of 5' deletion and linker-substitution mutants identified two critical positive cis elements, -314 to -295 and -284 to -255. An electrophoretic mobility-shift assay showed that nuclear proteins prepared from maize kernels interact with the 60-bp fragment containing these two elements. Expression of the Sbe1 gene is regulated by sugar concentration in suspension-cultured maize endosperm cells, and the region -314 to -145 is essential for this effect. Interestingly, the expression of mEmBP-1, a bZIP transcription activator, in suspension-cultured maize endosperm cells resulted in a 5-fold decrease in Sbe1 promoter activity, suggesting a possible regulatory role of the G-box present in the Sbe1 promoter from -227 to -220.