The altered gene expression seen in cancer could relate to differences in nonhistone chromatin proteins between normal and malignant tumor cells. Phenol-soluble nonhistone chromatin proteins were isolated from human normal and leukemic (chronic lymphocytic leukemia) B-cells, as well as long-term cultured human B-lymphocyte cell lines. High-resolution two-dimensional electrophoretic maps identified a group of three nuclear proteins with a molecular weight of 45,000 to 50,000 and an isoelectric range of 4.5 to 4.7, which were associated only with the human leukemic B-cells. Leukemic B-cells and cultured B-cell lines also expressed a variant form of nuclear actin and tubulin.
Supported by the Medical Research Council of Canada.