Degree of conservation of HeLa interphase nonhistone antigens in metaphase and with chromatin from non-human cells

Immunological procedures were applied to determine the degree of conservation of the nonhistone proteins of HeLa interphase chromatin. Polyacrylamide gels were overlaid with antiserum to HeLa interphase chromatin, and ¹²⁵I-Protein A was used to detect bound antibodies. With two-dimensional gels, more than 80 interphase species were found as components of metaphase chromosomes. The degree of conservation of HeLa nonhistone antigens with other chromatin sources was calculated through densitometry of autoradiograms and stained gels. Chromatin was obtained from chicken erythrocytes, Novikoff rat hepatoma cells, and mouse L cells, and the presence of one-quarter to one-third of the nonhistone antigens of HeLa chromatin was demonstrated.