A TGACGT motif in the 5'-upstream region of alpha-amylase gene from Vigna mungo is a cis-element for expression in cotyledons of germinated seeds.
Alpha-amylase is expressed at high levels in cotyledons of germinated seeds of Vigna mungo. The mRNA for alpha-amylase appeared in cotyledons of the seeds at 1 d after imbibition started (DAI). Two TGACGT motifs at -445 and at -125 in the promoter region of the gene interacted with nuclear proteins from cotyledons of dry seeds and the activities were detected until 3 DAI. A transient assay with particle bombardment showed that the downstream region from -135 in the promoter was required for high level expression in the cotyledons and the activity was reduced by mutation of the TGACGT motif at -125. The activities to bind the TGACGT motifs were detected in the axes of the seeds at 1 DAI but disappeared at 4 DAI, although the mRNA for alpha-amylase in the axes appeared at 4 DAI and increased in level by 6 DAI. A transient assay experiment showed that a positive regulatory element for the expression in the axes was located in the region from -630 to -453. These results indicated that the TGACGT motif at -125 was required for high level expression of the gene in the cotyledons of the germinated seeds.
Yamauchi
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Department of Biological Sciences, Tokyo Metropolitan University, Minami-ohsawa 1-1, Hachioji, Tokyo, 192-0397 Japan. yamauchi-daisuke@c.metro-u.ac.jp
D000595:Amino Acid Sequence; D001483:Base Sequence; D018548:Cotyledon / Q000201:enzymology; D018744:DNA, Plant; D004268:DNA-Binding Proteins / Q000378:metabolism; D007887:Fabaceae / Q000201:enzymology* / Q000235:genetics; D015870:Gene Expression; D018525:Germination; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D012639:Seeds / Q000201:enzymology / Q000254:growth & development; D016339:Spectrometry, Mass, Fast Atom Bombardment / Q000379:methods; D000516:alpha-Amylases / Q000235:genetics*
D018744:DNA, Plant; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D000516:alpha-Amylases