Studies on staining and localization of acidic nuclear proteins in the walker 256 carcinosarcoma.

A simple procedure for selective staining of acidic nuclear proteins is described, in which toluidine blue 0 was employed at pH 9. The acidic proteins are present in nucleoli, the nuclear ribonucleoprotein network, the region of nuclear membrane, and the cytoplasm. They are found also in intimate association with chromosomes in mitotic figures, and form a thin peripheral layer around them. Histones stained with Fast Green, according to Alfert and Geschwind, have exactly the opposite localization. They were found in all chromatin structures of the interphase nucleus, chromosomes in mitotic figures, and in chromatin septa in nucleoli.