| Research Abstract |
All trans retinoic acid(RA) enhanced the expression of craf mRNA in the megakaryoblastic leukemia cell line, CMK. Platelet derived growth factor(PDGF) also enhanced it, but the amount of it is small. IL-3, IL-6, GM-CSF, G-CSF, erythropoietin, phorbol ester(TPA), DMSO and gamma-interferon didn't show any change.
The expression of c-raf mRNA was initially increased by the treatment of RA, but strongly suppressed after 4 weeks of treatment. Stimulation by fetal calf serum(FCS) to the CMK cells, which were strongly suppressed the expression of c-raf mRNA by RA, induced the decrease in intensity of expression of c-fos mRNA compared with untreated cells. The expression of c-fos mRNA reached the maximal level at 15-30 minutes after FCS treatment in both cells. There was no difference of the expression of c-myc mRNA between these cells. This result indicated that raf gene may be related the signal transduction to fos gene not to myc gene.
Treatment of CMK cells by TPA intensively increased the expression of small GTP-binding protein, smg p21. The study of the relationship between the expression of c-raf gene and smg p21 gene is on going. CMK cells were induced the proliferation and/or differentiation by GM-CSF, IL-3, IL-6, and IL-11. The study of effects of these cytokines on CMK cells which were suppressed the expression of c-raf mRNA is also on going.
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