A novel temporal expression pattern of three C/EBP family members in differentiating myelomonocytic cells

• Published in: Blood 1992-10, Vol.80 (7), p.1725-1735
• Main Authors: Scott, L M, Civin, C I, Rorth, P, Friedman, A D
• Format: Article
• Language: English
• Subjects: Antigens, Surface - analysis; Blotting, Western; Bone Marrow - pathology; Bone Marrow Cells; Burkitt Lymphoma - pathology; CCAAT-Enhancer-Binding Proteins; Cell Differentiation; Cell Nucleus - physiology; Cells, Cultured; DNA-Binding Proteins - biosynthesis; DNA-Binding Proteins - genetics; DNA-Binding Proteins - isolation & purification; Gene Expression; Hematopoietic Stem Cells - cytology; Hematopoietic Stem Cells - drug effects; Hematopoietic Stem Cells - pathology; Humans; Interleukin-3 - pharmacology; Leukemia - pathology; Leukemia, Myeloid, Acute - pathology; Leukemia-Lymphoma, Adult T-Cell - pathology; Molecular Weight; Nuclear Proteins - biosynthesis; Nuclear Proteins - genetics; Nuclear Proteins - isolation & purification; RNA, Messenger - analysis; RNA, Messenger - genetics; Transcription Factors - biosynthesis; Transcription Factors - genetics; Transcription Factors - isolation & purification; Tumor Cells, Cultured
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.v80.7.1725.1725

Members of the CCAAT/enhancer binding protein (C/EBP) family have been shown to regulate the terminal differentiation of adipocytes and hepatocytes. In these cell lineages, high levels of C/EBP alpha are found only in mature, nondividing cells. Using Western blotting and immunohistochemical staining, we have determined the temporal order of expression for C/EBP alpha, C/EBP beta, and C/EBP delta in differentiating myelomonocytic marrow cells. These studies show a unique temporal pattern of C/EBP isoform expression in the myeloid lineage. In particular, C/EBP alpha expression is very high in proliferative myelomonocytic cells, and diminishes during phenotypic maturation. While we have detected C/EBP alpha, C/EBP beta, and C/EBP delta in multiple myeloid leukemia cell lines, and C/EBP alpha in normal myeloid cells and in de novo human myeloid leukemias, we have not detected these C/EBP isoforms in either erythroid or lymphoid cells. Finally, we show that C/EBP alpha, C/EBP beta, and C/EBP delta protein and messenger RNA levels correlate in maturing granulocytic cells. The formation of tissue-specific combinations of C/EBP homodimers and heterodimers may allow this family of transcription factors to regulate different sets of genes in adipocytes, hepatocytes, and myelomonocytes.