title: Another potential artifact in the study of nucleosome phasing by chromatin digestion with micrococcal nuclease.
abstract: We show that, contrary to expectations, restriction enzyme cleavage of chicken erythrocyte nucleosome core particle DNA generates a series of distinct subnucleosome fragments. These fragments do not result from bulk nucleosome phasing in vivo, but arise from micrococcal nuclease cleavages internal to the core particle, at roughly 10-base pair intervals and at AT-rich sequences. Those 145-base pair DNA fragments remaining intact are a biased population in which the guanine content can fluctuate by as much as 10%, with a 10-base pair period. We suggest that these same considerations, when applied to a unique DNA sequence, are the true explanation for several previous claims for nucleosome phasing.
mesh_terms: D000225:Adenine / Q000378:metabolism; D000818:Animals; D001482:Base Composition; D002645:Chickens; D002843:Chromatin / Q000378:metabolism*; D004247:DNA / Q000032:analysis / Q000378:metabolism; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004912:Erythrocytes; D008836:Micrococcal Nuclease / Q000378:metabolism*; D009707:Nucleosomes / Q000502:physiology*; D013941:Thymine / Q000378:metabolism
chemical_list: D002843:Chromatin; D009707:Nucleosomes; D004247:DNA; D004262:DNA Restriction Enzymes; D008836:Micrococcal Nuclease; D000225:Adenine; D013941:Thymine