A tobacco nuclear protein that preferentially binds to unmethylated CpG-rich DNA.
The methylation of cytosine residues in CpG dinucleotides of eukaryotic DNA is an important mechanism for the regulation of gene expression. Higher plants have a high content of methylated cytosine residues in CpG as well as CpNpG sites, and experimental evidence suggests a role in gene expression for DNA methylation. In this article, we describe a tobacco nuclear protein whose binding to various DNA sequences is positively correlated with the CpG density of the probes. This protein, CpG-binding protein 1 (CGBP-1), has reduced affinity for DNA when the CpG sites are methylated. Ribonuclease treatment also reduces the formation of the CGBP-1 complex. The binding characteristics of CGBP-1 make it an interesting protein with respect to methylation-mediated gene expression in plants.
Fisscher
U
U
Department of Molecular Cell Biology, University of Utrecht, The Netherlands.
Weisbeek
P
P
Smeekens
S
S
D001483:Base Sequence; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015226:Dinucleoside Phosphates / Q000378:metabolism*; D008745:Methylation; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D010947:Plants, Toxic; D010970:Plastocyanin / Q000235:genetics; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D014026:Nicotiana / Q000378:metabolism*
D004247:DNA; D004268:DNA-Binding Proteins; D015226:Dinucleoside Phosphates; D009687:Nuclear Proteins; D010970:Plastocyanin; C015772:CpG dinucleotide