Gordon G. Wong

Interleukin 4 is at 5q31 and interleukin 6 is at 7p15

SummaryDNA probes to the human interleukin 4 (IL4) and interleukin 6 (IL6) genes have been used for in situ hybridization to normal human chromosomes and Southern blot analysis of a series of mouse-human hybrid cell lines. IL4 maps to 5q31, the same location as IL5 and other haemopoietic growth factor genes. IL6 maps to 7p15. The significance of these locations is discussed.

Production of human interleukin for DA cells (HILDA)/leukemia inhibitory factor (LIF) by activated monocytes

We demonstrate mRNA accumulation and production of HILDA/LIF by human activated Mo, monocyte-derived macrophages and myelomonocytic cell lines. Among the various stimuli tested, the synergistic combination of phorbol diester and VD3 was the most potent inducer of HILDA/LIF gene expression. The kinetics of mRNA accumulation on activated Mo showed a stimulation peak at 24 hr which declined thereafter. HILDA/LIF activity in culture supernatants was detected at 24 hr and reached a plateau at 72 hr of culture. In contrast to Mo, PBL did not accumulate HILDA/LIF mRNA upon culture with PDBu and VD3, whereas PHA and the combination of PDBu and A23187 induced HILDA/LIF mRNA accumulation and secretion in the culture supernatant. To exclude the possibility that HILDA/LIF was produced by contaminating PBL, highly enriched Mo preparations were used, which were devoid of T cells as assessed by the absence of TCR-beta chain mRNA transcripts. HILDA/LIF production by monocytic cells was further documented by the capacity of stimulated U937 cell conditioned medium to compete with 125I-labeled nHILDA/LIF for binding to its receptor on murine M1 cells. Under the synergistic effect of PDBu and VD3 stimulation, Mo-derived macrophages as well as HL-60 and U937 cell lines accumulated HILDA/LIF mRNA and produced this cytokine with identical kinetics as for Mo. Finally, we show that HILDA/LIF mRNA accumulation in U937 cells upon stimulation with PDBu, or the combination of PDBu and VD3, was inhibited in the presence of the protein synthesis inhibitor CHX. These results document for the first time that human Mo, when stimulated appropriately in vitro, can express the HILDA/LIF gene and its product, and that intermediate proteins must be newly synthesized in this process.

An NMR probe for the study of aerobic suspensions of cells and organelles

Abstract We describe the construction of an NMR probe and cell chamber with good mixing, pH buffering, and oxygenation characteristics, which can be used for relatively dilute cell and organelle suspensions. The 31 P NMR spectra of acceptable signal-to-noise ratios are obtained from approximately 200 mg (protein) of tissues, and kinetic studies of mitochondrial oxidative phosphorylation are demonstrated. Representative spectra from rabbit kidney cortical tubules and rabbit kidney cortical mitochondria are presented.

Localization of the human G-CSF gene to the region of a breakpoint in the translocation typical of acute promyelocytic leukemia

SummaryThe colony-stimulating factors regulate growth, differentiation, and function of blood cells. The effect of granulocyte colony-stimulating factor (G-CSF) on myeloid leukemias is unique among colony-stimulating factors in driving the leukemic cells from a self-renewing malignant state to a mature differentiated phenotype with the concomitant loss of tumorigenicity. This property of G-CSF has led to suggestions that its absence is responsible for lack of differentiation of leukemic cells and that the therapeutic administration of G-CSF could reverse this defect and result in a cure for leukemia. Here we show that the gene coding for human G-CSF is localized to chromosome 17, bands q11.2-21. The translocation of the long arm of chromosome 17 at q12-21 to chromosome 15 is a specific abnormality occurring in a high proportion of, if not all, patients with acute promyelocytic leukemia, a disease characterized by undifferentiated myeloid cells and a dismal prognosis. Abnormalities of the regulation of a specific differentiation factor gene mediated by a specific chromosomal rearrangement may be directly implicated in the pathogenesis of human leukemia.