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High mobility group proteins HMG‐1 and HMG‐I/Y bind to a positive regulatory region of the pea plastocyanin gene promoter
Author(s) -
Webster Carl I.,
Packman Leonard C.,
Pwee KengHock,
Gray John C.
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.1997.11040703.x
Subject(s) - plastocyanin , high mobility group , biology , oligonucleotide , dna binding protein , binding site , microbiology and biotechnology , hmg coa reductase , gene , hmg box , biochemistry , escherichia coli , binding protein , transcription factor , reductase , enzyme , photosystem i , chloroplast
A 268 bp region (P268) of the pea plastocyanin gene promoter responsible for high‐level expression has been shown to interact with the high mobility group proteins HMG‐1 and HMG‐I/Y isolated from pea shoot chromatin. cDNAs encoding an HMG‐1 protein of 154 amino acid residues containing a single HMG‐box and a C‐terminal acidic tail and an HMG‐I/Y‐like protein of 197 amino acid residues containing four AT‐hooks have been isolated and expressed in Escherichia coli to provide large amounts of full‐length proteins. DNase I footprinting identified eight binding sites for HMG‐I/Y and six binding sites for HMG‐1 in P268. Inhibition of binding by the antibiotic distamycin, which binds in the minor groove of A/T‐rich DNA, revealed that HMG‐I/Y binding was 400‐fold more sensitive than HMG‐1 binding. Binding‐site selection from a pool of random oligonucleotides indicated that HMG‐I/Y binds to oligonucleotides containing stretches of five or more A/T bp and HMG‐1 binds preferentially to oligonucleotides enriched in dinucleotides such as TpT and TpG.