A novel family of plant DNA-binding proteins containing both HMG-box and AT-rich interaction domains.
The A/T-rich interaction domain (ARID) and the HMG-box domain represent DNA-interaction modules that are found in sequence-specific as well as nonsequence-specific DNA-binding proteins. Both domains are found in a variety of DNA-interacting proteins in a wide range of eukaryotic organisms. Proteins that contain both an ARID and an HMG-box domain, here termed ARID-HMG proteins, appear to be specific for plants. This protein family is conserved in higher plants (both mono- and dicot plants) as well as lower plants such as the moss Physcomitrella. Since ARID-HMG proteins have not been studied experimentally, we have examined here two family members from Arabidopsis. The genes encoding ARID-HMG1 and ARID-HMG2 are widely expressed in Arabidopsis but at different levels. Subcellular localization experiments studying ARID-HMG1 and ARID-HMG2 fused to GFP by fluorescence microscopy show that both proteins localize primarily to cell nuclei. Analyses of the DNA-binding properties using electrophoretic mobility shift assays revealed that mediated by the HMG-box domain, ARID-HMG1 binds structure specifically to DNA minicircles. Mediated by the ARID, the protein binds preferentially to A/T-rich DNA, when compared with G/C-rich DNA. Therefore, both DNA-binding domains contribute to the DNA interactions of ARID-HMG1. Accordingly, the protein combines DNA-binding properties characteristic of ARID and HMG-box proteins.
Hansen
Frederik T
FT
Department of Life Sciences, Aalborg University, Sohngaardsholmsvej 49, DK-9000 Aalborg, Denmark.
Madsen
Claus K
CK
Nordland
Anne Mette
AM
Grasser
Marion
M
Merkle
Thomas
T
Grasser
Klaus D
KD
D020856:AT Rich Sequence; D000595:Amino Acid Sequence; D000818:Animals; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D019068:Bryopsida / Q000737:chemistry / Q000378:metabolism; D018744:DNA, Plant / Q000737:chemistry* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D024742:HMG-Box Domains; D008969:Molecular Sequence Data; D012275:Oryza / Q000737:chemistry / Q000378:metabolism; D032107:Populus / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D003313:Zea mays / Q000737:chemistry / Q000378:metabolism
D029681:Arabidopsis Proteins; D018744:DNA, Plant; D004268:DNA-Binding Proteins