Epigenetic nucleosomes: Alu sequences and CG as nucleosome positioning element.
Alu sequences carry periodical pattern with CG dinucleotides (CpG) repeating every 31-32 bases. Similar distances are observed in distribution of DNA curvature in crystallized nucleosomes, at positions +/-1.5 and +/-4.5 periods of DNA from nucleosome DNA dyad. Since CG elements are also found to impart to nucleosomes higher stability when positioned at +/-1.5 sites, it suggests that CG dinucleotides may play a role in modulation of the nucleosome strength when the CG elements are methylated. Thus, Alu sequences may harbor special epigenetic nucleosomes with methylation-dependent regulatory functions. Nucleosome DNA sequence probe is suggested to detect locations of such regulatory nucleosomes in the sequences.
Salih
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F
Genome Diversity Center, Institute of Evolution, University of Haifa, Israel.
Salih
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B
Kogan
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S
Trifonov
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EN
D020087:Alu Elements / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D002645:Chickens; D018900:Dinucleotide Repeats / Q000235:genetics*; D044127:Epigenesis, Genetic; D005914:Globins / Q000235:genetics*; D008969:Molecular Sequence Data; D009707:Nucleosomes / Q000502:physiology*; D012689:Sequence Homology, Nucleic Acid
D009707:Nucleosomes; D005914:Globins