Tropomyosin is localized in the nuclear matrix and chromosome scaffold of physarum polycephalum

The nuclei and chromosomes were isolated from plasmodia of Physarum polycephalum. The nuclear matrir and chromosome scaffold were obtained after the DNA and most of the proteins were extracted with DNase I and 2 M NaCl. SDS-PAGE analyses revealed that the nuclear matrir and chromosome scaffold contained a 37 kD polypeptide which is equivalent to tropomyosin in molecular weight. Immunofluorescence observations upon slide preparations labeled with anti-tropomyosin antibody showed that the nuclear matrix and chromosome scaffold emanated bright fluorescence, suggesting the presence of the antigen in them.Immunodotting results confirmed the presence of tropomyosin in the nuclear matrix and chromosome scaffold. Immunoelectron microscopic obserwtions further demonstrated that tropomyosin was dispersively distributed in the interphase nuclei and metaphase chromosomes.