Human leukemic cells: Cytochemical studies on nuclear proteins

The DNA:histone ratios have been determined by quantitative cytochemical analyses of individual cells in populations of human lymphocytic cells derived in continuous culture from the peripheral blood buffy coats of patients with acute leukemia or infectious mononucleosis. These populations of lymphocytic cells were quite similar with respect to the Feulgen-DNA and protein content per cell. The close association between DNA and histone was reflected in their similar patterns of distribution in fixed and stained cells; and further evidenced by similarities in the DNA: histone ratios characteristic of these different populations of lymphocytic cells. — Chemical acetylation and methylation of nuclear proteins of these cell populations exhibited some quantitative differences. The chemically acetylated histone content was less, and chemically methylated histone content was greater in cells derived from acute leukemia or infectious mononucleosis than in normal human lymphocytes. These quantitative differences in chemical acetylation and methylation may contribute to specific structural alterations in these histones which modify their functional capacity with respect to interactions with DNA. Such alterations may relate to differences in gene expression as reflected, for example, by the biological and biochemical differences among these human lymphocytic cells.These studies were supported in part by research grants C-6516 from the National Cancer Institute and FR-05526 from the Division of Research Facilities and Resources, National Institutes of Health.Holds Research Career Award K6-CA-22,150 from the National Cancer Institute, National Institutes of Health.