Interaction of wheat high-mobility-group proteins with four-way-junction DNA and characterization of the structure and expression of HMGA gene.
Plant high-mobility-group (HMG) chromosomal proteins are the most abundant and ubiquitous nonhistone proteins found in the nuclei of higher eukaryotes. There are only two families of HMG proteins, namely, HMGA and HMGB in plants. The cDNA encoding wheat HMGa protein was isolated and characterized. Wheat HMGA cDNA encodes a protein of 189 amino acid residues. At its N terminus, there is a histone H1-like structure, which is a common feature of plant HMGA proteins, followed by four AT-hook motifs. Polymerase chain reaction results show that the gene contains a single intron of 134 bp. All four AT-hook motifs are encoded by the second exon. Northern blot results show that the expression of HMGA gene is much higher in organs undergoing active cell proliferation. Gel retardation analysis show that wheat HMGa, b, c and histone H1 bind to four-way-junction DNA with high binding affinity, but affinity is dramatically reduced with increasing Mg(2+) and Na(+) ion concentration. Competition binding studies show that proteins share overlapping binding sites on four-way-junction DNA. HMGd does not bind to four-way-junction DNA.
Zhang
Wensheng
W
Department of Biological Sciences, Faculty of Science, National University of Singapore, 10 Kent Ridge Crescent, 117543, Singapore, Singapore.
Wu
Qiang
Q
Pwee
Keng Hock
KH
Manjunatha Kini
R
R
D024761:AT-Hook Motifs; D000595:Amino Acid Sequence; D001483:Base Sequence; D002455:Cell Division; D018744:DNA, Plant / Q000737:chemistry / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005091:Exons; D018506:Gene Expression Regulation, Plant; D024003:HMGA Proteins / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D024002:HMGB Proteins / Q000187:drug effects / Q000378:metabolism; D006609:High Mobility Group Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D006657:Histones / Q000187:drug effects / Q000378:metabolism; D007438:Introns; D008274:Magnesium / Q000494:pharmacology; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D017434:Protein Structure, Tertiary; D012964:Sodium / Q000494:pharmacology; D013095:Spermidine / Q000494:pharmacology; D014908:Triticum / Q000235:genetics* / Q000378:metabolism*
D018744:DNA, Plant; D004268:DNA-Binding Proteins; D024003:HMGA Proteins; D024002:HMGB Proteins; D006609:High Mobility Group Proteins; D006657:Histones; D009687:Nuclear Proteins; D010940:Plant Proteins; D012964:Sodium; D008274:Magnesium; D013095:Spermidine