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Characterization of a DNA‐binding protein that interacts with 5′ flanking regions of two fruit‐ripening genes
Author(s) -
Coupe Simon A.,
Deikman Jill
Publication year - 1997
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1997.11061207.x
Subject(s) - ripening , gene , biology , dna , transcription factor , promoter , binding protein , microbiology and biotechnology , complementary dna , dna binding site , recombinant dna , binding site , binding domain , dna binding domain , dna binding protein , biochemistry , gene expression , genetics , food science
The E4/E8 binding protein (E4/E8BP) interacts with sequences in the 5′ flanking regions of two genes, E4 and E8 , that are coordinately regulated by ethylene during tomato fruit ripening. The DNA‐binding activity of this protein increases during fruit ripening, and it may play a role in regulation of these genes. To begin to understand the function of this protein, a cDNA has been isolated that encodes a protein, E4/E8BP‐1, with DNA‐binding specificity similar to that of E4/E8BP. This DNA‐binding protein is closely related to a DNA binding protein from tobacco, 3AF1, that interacts with the promoter of the pea rbcS‐3A gene. A repeated domain was identified within the predicted 3AF1 amino acid sequence, which includes a series of histidines and cysteines, suggestive of zinc binding, and this repeat is conserved in E4/E8BP‐1. Interaction of both E4/E8BP‐1 and nuclear extracts from ripening fruit with the E8 recognition sequence is sensitive to 1,10‐phenanthroline, indicating that a metal is required for binding of both the native and recombinant proteins. The mRNA for E4/E8BP‐1 is moderately abundant in fruit, and increases slightly during fruit ripening, consistent with a role in fruit ripening. A truncated version of E4/E8BP‐1 was able to transactivate the E4 promoter in transient assay, demonstrating that this DNA‐binding protein can interact with the E4 promoter in vivo to enhance gene transcription.