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目的 :利用小鼠前成骨细胞系MC3T3 E1初探FGF2对BMPS Smads信号转导通路的调节机制。方法 :构建含 5个串联的来源于Smad6启动子的R Smads结合序列 (GC2 )的荧光素酶报告基因质粒 ( 5GC2 Lux)。以该质粒探讨FGF2对BMP组成活化型受体I(caALK 2 )激活的Smad5转录调控能力的影响。外源转染去除Smad5分子中MEK ERK通路磷酸化位点的突变体 ,探讨FGF2伙化的MEK ERK对BMPS Smads通路的调节作用。结果 :所构建报告基因质粒能够特异反映Smads的转录激活能力的变化。FGF2能够显著下调BMP组成活化型受体(caALK2 )激活的Smad5转录调控能力。外源转染Smad5突变分子仅能部分逆转FGF2对Smads通路的负调节效应。结论 :FGF2参与调节BMPs活化的信号通路可能不仅限于通过活化MEK ERK信号转导通路来下调Smads转录调控活性
OBJECTIVE: To investigate the regulatory mechanism of FGF2 on BMPS Smads signal transduction pathway by using mouse pre-osteoblastic cell line MC3T3 E1. METHODS: A luciferase reporter plasmid (5GC2 Lux) containing 5 Smad6 promoter-derived R Smads binding sequences (GC2) in tandem was constructed. The plasmid was used to investigate the effect of FGF2 on the transcriptional regulation of Smad5 activated by BMP2-activated receptor I (caALK2). Exogenous transfection removes the mutants of phosphorylation site of MEK ERK pathway in Smad5, and explores the regulation of MEK ERK by FGF2 on BMPS Smads pathway. Results: The constructed reporter plasmids could specifically reflect the transcriptional activation of Smads. FGF2 significantly down-regulated the transcriptional regulation of Smad5 activated by BMP-activating receptor (caALK2). Exogenous transfected Smad5 mutant molecules can only partly reverse the negative regulatory effect of FGF2 on Smads pathway. Conclusion: The signaling pathways by which FGF2 is involved in the regulation of BMPs activation may not be limited to the down-regulation of Smads transcriptional regulation by activating the MEK ERK signal transduction pathway