title: Isolation of a residual protein structure from nuclei of the myxomycete Physarum polycephalum.
abstract: A nuclear framework structure has been obtained from isolated interphase nuclei of Physarum polycephalum by extraction with 2.5 M NaCl and subsequent digestion with DNase. Whole-mount electron micrographs showed a nuclear lamina containing residual pore structures associated with the fibrous internal matrix. The matrix was continuous with fibrillar remnants of the nucleolus. The structure was shown to consist of 2 major polypeptides of 23,000 and 36,500 Daltons as well as 30 to 40 minor polypeptides of various molecular weight classes. The 2 major polypeptides were also prominent in preparations of the residual nucleolar material, suggesting that matrix proteins are common to both structures. The predominance of low-molecular-weight polypeptides in Physarum nuclear matrix suggests that there may be significant differences in composition of nuclear structural proteins between lower and higher eukaryotes.
mesh_terms: D002466:Cell Nucleolus / Q000032:analysis; D002467:Cell Nucleus / Q000032:analysis / Q000648:ultrastructure*; D004591:Electrophoresis, Polyacrylamide Gel; D005656:Fungal Proteins / Q000302:isolation & purification*; D007399:Interphase; D008970:Molecular Weight; D010804:Physarum / Q000032:analysis / Q000648:ultrastructure*
chemical_list: D005656:Fungal Proteins