A major nucleolar protein, nucleolin, induces chromatin decondensation by binding to histone H1.
Using circular dichroism to probe the extent of DNA condensation in chromatin, we have demonstrated that a major nucleolar protein, nucleolin can decondense chromatin. By means of various binding assays we show that nucleolin has a strong affinity for histone H1 and that the phosphorylated N-terminal domain, rich in lengthy stretches of acidic amino acids, is responsible for this ionic interaction. Additional experiments clearly demonstrate that nucleolin is unable to act as a nucleosome core assembly or disassembly factor and hence has little affinity for the core histone octamer. We propose that this nucleolar protein induces chromatin decondensation by binding to histone H1, and that nucleolin can therefore be regarded as a protein of the high-mobility-group type.
Erard
M S
MS
Centre de Recherche de Biochimie et de Génétique Cellulaires du CNRS, Toulouse, France.
Belenguer
P
P
Caizergues-Ferrer
M
M
Pantaloni
A
A
Amalric
F
F
D000595:Amino Acid Sequence; D001665:Binding Sites / Q000187:drug effects; D002843:Chromatin / Q000187:drug effects*; D002846:Chromatography, Affinity; D002942:Circular Dichroism; D004247:DNA / Q000378:metabolism; D006657:Histones / Q000378:metabolism*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000494:pharmacology*; D010446:Peptide Fragments / Q000032:analysis; D010750:Phosphoproteins / Q000494:pharmacology*; D010766:Phosphorylation; D016601:RNA-Binding Proteins; D013329:Structure-Activity Relationship; D000097796:Nucleolin
D002843:Chromatin; D004247:DNA; D006657:Histones; D009687:Nuclear Proteins; D010446:Peptide Fragments; D010750:Phosphoproteins; D016601:RNA-Binding Proteins; D000097796:Nucleolin