DNA binding specificity of the wheat bZIP protein EmBP-1.
EmBP-1 is a wheat DNA binding protein of the basic leucine zipper (bZIP) class of transcription factors implicated in the mechanisms of abscisic acid mediated gene activation. Understanding the role of EmBP-1 in regulating gene transcription requires elucidation of its DNA binding specificity. The binding of EmBP-1 was studied using gel shift selection of DNA from random sequence pools. DNA binding sites were identified by sequencing of a selected pool and by cloning and sequencing individual sites. The binding sites were compared by mobility shift assay and DNase I footprinting, which show that EmBP-1 binds to a family of sequences with varying degrees of affinity. The highest affinity site bound by EmBP-1 is the palindrome GCCACGTGGC. EmBP-1 also binds several other sequences with high affinity, however most of these are asymmetric. While nearly all sequences bound by EmBP-1 contain an ACGT core sequence, EmBP-1 can also bind at least two sites with altered cores. These results provide a basis for comparing the DNA binding specificity of EmBP-1 with those of other plant bZIP proteins and provide insight into the possible target sites which EmBP-1 might bind in vivo.
Niu
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Department of Horticulture, Pennsylvania State University, University Park 16802.
Guiltinan
M J
MJ
D000595:Amino Acid Sequence; D001483:Base Sequence; D050976:Basic-Leucine Zipper Transcription Factors; D001665:Binding Sites; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism*; D018076:DNA, Complementary / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D051790:G-Box Binding Factors; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D017343:Genes, Plant / Q000235:genetics*; D008969:Molecular Sequence Data; D011089:Polydeoxyribonucleotides / Q000138:chemical synthesis; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000378:metabolism; D017422:Sequence Analysis, DNA; D014157:Transcription Factors; D014158:Transcription, Genetic / Q000235:genetics; D015533:Transcriptional Activation; D014908:Triticum / Q000235:genetics*
D050976:Basic-Leucine Zipper Transcription Factors; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D051790:G-Box Binding Factors; D011089:Polydeoxyribonucleotides; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D004247:DNA