Johnson J A, Nathanson N M
Department of Pharmacology, School of Medicine, University of Washington, Seattle 98195.
J Biol Chem. 1994 Jul 22;269(29):18856-63.
This study used reporter gene constructs containing regulatory regions of the c-fos, vasoactive intestinal peptide, and choline acetyltransferase genes to determine the role of p21ras and protein kinase C in the action of ciliary neurotrophic factor and leukemia inhibitory factor. Down-regulation of protein kinase C with phorbol ester did not affect the induction of either c-fos-beta-galactosidase or vasoactive intestinal peptide-luciferase by ciliary neurotrophic factor or leukemia inhibitory factor. In contrast, while leukemia inhibitory factor induction of choline acetyltransferase-luciferase expression was protein kinase C-independent, there appears to be both protein kinase C-dependent and -independent pathways for induction of choline acetyltransferase-luciferase by ciliary neurotrophic factor. Cotransfection of a dominant-negative mutant p21rasN17 blocked nerve growth factor-mediated induction of c-fos-beta-galactosidase, but did not affect induction of c-fos-beta-galactosidase, vasoactive intestinal peptide-luciferase, or choline acetyltransferase-luciferase by either ciliary neurotrophic factor or leukemia inhibitory factor. Thus, in contrast to the action of nerve growth factor, gene induction by ciliary neurotrophic factor, and leukemia inhibitory factor is ras-independent in IMR-32 neuroblastoma cells.
本研究使用了包含c-fos、血管活性肠肽和胆碱乙酰转移酶基因调控区的报告基因构建体，以确定p21ras和蛋白激酶C在睫状神经营养因子和白血病抑制因子作用中的角色。用佛波酯下调蛋白激酶C并不影响睫状神经营养因子或白血病抑制因子对c-fos-β-半乳糖苷酶或血管活性肠肽-荧光素酶的诱导。相反，虽然白血病抑制因子对胆碱乙酰转移酶-荧光素酶表达的诱导不依赖于蛋白激酶C，但睫状神经营养因子诱导胆碱乙酰转移酶-荧光素酶似乎存在蛋白激酶C依赖和非依赖的途径。共转染显性负性突变体p21rasN17可阻断神经生长因子介导的c-fos-β-半乳糖苷酶诱导，但不影响睫状神经营养因子或白血病抑制因子对c-fos-β-半乳糖苷酶、血管活性肠肽-荧光素酶或胆碱乙酰转移酶-荧光素酶的诱导。因此，与神经生长因子的作用相反，在IMR-32神经母细胞瘤细胞中，睫状神经营养因子和白血病抑制因子的基因诱导不依赖于ras。
