IMMUNOCYTOCHEMICAL LOCALIZATION OF S-100 PROTEIN AND CALMODULIN IN C6 GLIOMA CELLS

Abstract

The localization of S-100, calmodulin and tubulin in the cultured C6 glioma cells was observed with the indirect immunoperoxidase method. The direct immunoperoxidase method for S-100 was also employed. The reaction products for S-100, calmodulin and tubulin were all found over filamentous structures in the interphase cells. Calmodulin and tubulin seemed to be localized in the cytoplasm, while S-100 was exhibited as intense granular reaction product in the nuclei.
In the mitotic cells, these proteins were shown to be present with characteristic localization in the mitotic apparatus. Calmodulin-specific staining was highly intense at the spindle poles.
In contrast, S-100 was shown to be concentrated on the chromosomes in all phases of mitotic cells. The direct method showed more accurate and defined localization of S-100 than the indirect method. This is the first demonstration of the possible interrelationship between S-100 protein and chromosome, although the biological significance of the fact is not known at present.