Columnar structure of SV40 minichromosome

Abstract

Like the sequence of the strongest 601 clone nucleosome of Lowary and Widom, the SV40 genome sequence contains tracks of YR dinucleotides separated by small integers of the 10.4n base series (10, 11, 21 and 30 bases). The tracks, however, substantially exceed the nucleosome DNA size and, thus, correspond to more extended structure - columnar chromatin. The micrococcal nuclease digests of the SV40 chromatin do not show uniquely positioned individual nucleosomes. This confirms the columnar structure of the minichromosome, as well as earlier electron microscopy studies.

Keywords

• nucleosome
• sequence periodicity
• YR dinucleotides
• YR tracks
• stacked nucleosomes
• rotational positioning
• nucleosome sliding
• nucleosome mapping