title: Structural organization of a hypermethylated nuclear DNA component in Physarum polycephalum.
abstract: Digestion of Physarum polycephalum nuclear DNA using the restriction endonuclease HpaII generates two components, distinguishable on the basis of their molecular size. The high-molecular-weight, HpaII-resistant component, which accounts for 20% of the DNA, contains a fivefold greater concentration of 5-methylcytosine residues than the low-molecular-weight HpaII-digested fraction. Segments of hypermethylated (M+) DNA are largely composed of a single, long, highly repeated sequence, and this major element is sometimes associated with other less highly repetitive sequences in the M+ DNA fraction. Restriction mapping of cloned Physarum M+ DNA segments, and Southern blot analysis of genomic DNA using subcloned segments of M+ DNA as a probe, provide evidence for sequence variation within different copies of the dominant highly repeated element, and possibly the other associated repeats in M+ DNA, and additionally that almost complete tandemly repeated copies of the major repeat are found in some M+ DNA segments.
authors.forename: O P
authors.initials: OP
authors.lastname: Peoples
authors.forename: P A
authors.initials: PA
authors.lastname: Whittaker
authors.forename: D
authors.initials: D
authors.lastname: Pearston
authors.forename: N
authors.initials: N
authors.lastname: Hardman
mesh_terms: D044503:5-Methylcytosine; D001482:Base Composition; D002851:Chromatography, High Pressure Liquid; D003596:Cytosine / Q000031:analogs & derivatives; D004262:DNA Restriction Enzymes; D004271:DNA, Fungal / Q000235:genetics*; D004587:Electrophoresis, Agar Gel; D008745:Methylation; D009693:Nucleic Acid Hybridization; D010804:Physarum / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid
chemical_list: D004271:DNA, Fungal; D044503:5-Methylcytosine; D003596:Cytosine; D004262:DNA Restriction Enzymes