Characterization of human leukemia and Burkitt lymphoma cells by their acidic nuclear protein profiles.

Abstract

Summary The content of the acidic nuclear proteins in various types of human leukemia cells, normal lymphocytes, and Burkitt lymphoma cells grown in tissue culture has been examined. Human leukemias could be distinguished from each other and from other tissues by the banding pattern of the acidic nuclear proteins observed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The banding profile of the nuclear protein extracts from leukemia cells obtained from peripheral blood indicated a lack of the higher-molecular-weight nuclear protein species that are present in metabolically active tissue or in dividing cell populations. A correlation could be made between the activity of the leukocyte cell types in nucleic acid and protein synthesis and the content of the higher-molecular-weight acidic nuclear proteins. In general, cells that were more actively engaged in nucleic acid and protein synthesis contained larger amounts of high-molecular-weight proteins. Moreover, when chronic lymphocytic leukemia cells were stimulated to divide in tissue culture by the addition of phytohemagglutinin, the banding profile of the acidic nuclear proteins obtained from these cells was converted to a profile that was very similar to that of cultured Burkitt lymphoma cells. This alteration in protein content occurred prior to the onset of DNA synthesis and at a time when cell viability was 80 to 90% of the original cultured cells. Thus, the events leading to the onset of DNA synthesis and cell division in a previously dormant population of cells were accompanied by a significant shift in the type of acidic nuclear proteins contained in the cells. These findings may relate to the control of gene readout and to the events involved in malignant transformation of mammalian cells.