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Nuclear c‐myc protein, maturation, and cell‐cycle status of human haemopoietic cells
Author(s) -
Bains M. A.,
Hoy T. G.,
Baines P.,
Jacobs A.
Publication year - 1987
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1987.tb02350.x
Subject(s) - myeloid , biology , mitosis , cell cycle , microbiology and biotechnology , bone marrow , hl60 , haematopoiesis , flow cytometry , promyelocyte , cell culture , cell , stem cell , cancer research , immunology , biochemistry , genetics
Summary Human c‐myc protein, p62 c‐myc , has been quantitated by flow cytometry in the nuclei of normal marrow and peripheral blood cells, and the HL60 cell line. Marrow and peripheral blood cells exhibit nuclear c‐myc protein throughout the cell‐cycle, at an average level 2–3–fold lower than HL60 cells. In no cells did p62 c‐myc vary more than 2‐fold throughout the cell cycle. A small subset of marrow G o /G 1 cells, enriched in early myeloid and blast cell fractions, contained p62 c‐myc at levels equal to or even exceeding those of HL60. Overall c‐myc protein content was higher in myeloid, compared to erythroid and lymphoid marrow fractions. Within the myeloid lineage, the highest average p62 c‐myc level was present in cells of intermediate maturation, i.e. myelocytes and metamyelocytes. In the erythroid lineage, c‐myc protein level was highest in the most immature cells and declined with maturation. Significant amounts of p62 c‐myc were present in post‐mitotic, end‐stage neutrophils, but were barely detectable in cycling late erythroblasts or in quiescent lymphocytes and monocytes. HL60 cells, despite c‐myc gene amplification and increased gene expression, contain c‐myc protein at a level corresponding to promyelocytes in normal human marrow. The virtual absence of p62 c‐myc in cycling late erythroblasts, and its presence in post‐mitotic end‐stage granulocytes, suggests that c‐myc protein may have functions unrelated to cell proliferation.