The C-terminal domain of the Arabidopsis AtMBD7 protein confers strong chromatin binding activity.
The Arabidopsis MBD7 (AtMBD7) - a naturally occurring poly MBD protein - was previously found to be functional in binding methylated-CpG dinucleotides in vitro and localized to highly methylated chromocenters in vivo. Furthermore, AtMBD7 has significantly lower mobility within the nucleus conferred by cooperative activity of its three MBD motifs. Here we show that besides the MBD motifs, AtMBD7 possesses a strong chromatin binding domain located at its C-terminus designated sticky-C (StkC). Mutational analysis showed that a glutamic acid residue near the C-terminus is essential though not sufficient for the StkC function. Further analysis demonstrated that this motif can render nuclear proteins highly immobile both in plant and animal cells, without affecting their native subnuclear localization. Thus, the C-terminal, StkC motif plays an important role in fastening AtMBD7 to its chromosomal, CpG-methylated sites. It may be possible to utilize this motif for fastening nuclear proteins to their chromosomal sites both in plant and animal cells for research and gene therapy applications.
Zemach
Assaf
A
Department of Plant Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel.
Paul
Laju K
LK
Stambolsky
Perry
P
Efroni
Idan
I
Rotter
Varda
V
Grafi
Gideon
G
D019943:Amino Acid Substitution / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism*; D047369:Chromatin Immunoprecipitation; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004058:Diffusion; D036681:Fluorescence Recovery After Photobleaching; D018698:Glutamic Acid / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D056968:Lac Repressors / Q000235:genetics / Q000378:metabolism; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding / Q000235:genetics; D054730:Protein Interaction Domains and Motifs / Q000502:physiology*; D011523:Protoplasts / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D014170:Transformation, Genetic; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism
D029681:Arabidopsis Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D056968:Lac Repressors; C516650:MBD5 protein, Arabidopsis; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D016159:Tumor Suppressor Protein p53; C443901:like heterochromatin protein 1; D018698:Glutamic Acid; D004247:DNA; C525054:MBD7 protein, Arabidopsis