翻译调控在紫外线C光诱导的环氧合酶-2表达中的作用。
The role of translational regulation in ultraviolet C light-induced cyclooxygenase-2 expression.
作者信息
László Csaba F, Fayad Sherine, Carpenter Oliver L, George Kimberly S, Lu Wei, Saad Abir Adel Abdel-Razak, Wu Shiyong
机构信息
Edison Biotechnology Institute and Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701, USA.
出版信息
Life Sci. 2009 Jul 3;85(1-2):70-6. doi: 10.1016/j.lfs.2009.04.018. Epub 2009 May 5.
AIMS
The role of ultraviolet C light (UVC)-induced phosphorylation of the eukaryotic initiation factor 2 (eIF2) in the regulation of cyclooxygenase-2 (COX-2) expression at both transcriptional and translational levels is investigated.
MAIN METHODS
Western analysis was used to determine COX expressions. Immunoprecipitation after [(35)S]-Met/Cys metabolic labeling was used to determine the rate for COX-2 synthesis and turnover. Quantitative real-time PCR was used to determine COX-2 mRNA levels. Ingenuity Pathways Analysis 6 was used for mapping COX-2 activation network.
KEY FINDINGS
UVC induces COX-2 expression in wild-type mouse embryo fibroblasts (MEF(S/S)) and that the inducibility is reduced in MEF(A/A) cells in which the phosphorylation site, Ser-51 in the eIF2alpha, is replaced with a nonphosphorylatable Ala (S51A). UVC-induced transcription of COX-2 is delayed in MEF(A/A) cells, which correlates with NF-kappaB activation as previously reported (Wu, S, Tan, M, Hu, Y, Wang, JL, Scheuner, D, Kaufman, RJ, Ultraviolet light activates NFkappaB through translational inhibition of IkappaBalpha synthesis. The Journal of Biological Chemistry, 279, 34898-34902, 2004). The translational efficiency of COX-2 is higher in MEF(A/A) cells than in MEF(S/S) cells at 4 h, but not at 24 h post-UVC. The translation efficiency is correlated to the ratio of activated COX-2 binding protein HuR/TIAR. In addition, the newly synthesized COX-2 protein is more stable in MEF(A/A) cells than in MEF(S/S) cells. The results demonstrated a complex and dynamic regulation of COX-2 expression.
SIGNIFICANCE
UVC induces a prolonged expression of COX-2. While transcriptional regulation of COX-2 expression is intensively studied, the role of translational regulation of COX-2 synthesis upon UVC-irradiation is not yet clear. This study elucidated a novel eIF2alpha phosphorylation-centered network for the regulation of COX-2 expression after UVC-irradiation.
目的
研究紫外线C光（UVC）诱导的真核起始因子2（eIF2）磷酸化在转录和翻译水平上对环氧合酶-2（COX-2）表达调控中的作用。
主要方法
采用蛋白质免疫印迹分析来确定COX的表达。在[（35）S]-甲硫氨酸/半胱氨酸代谢标记后进行免疫沉淀，以确定COX-2的合成和周转速率。采用定量实时PCR来确定COX-2 mRNA水平。运用Ingenuity Pathways Analysis 6绘制COX-2激活网络。
主要发现
UVC可诱导野生型小鼠胚胎成纤维细胞（MEF（S/S））中COX-2的表达，而在eIF2α中磷酸化位点Ser-51被不可磷酸化的丙氨酸（S51A）取代的MEF（A/A）细胞中，这种诱导性降低。COX-2的UVC诱导转录在MEF（A/A）细胞中延迟，这与先前报道的核因子κB（NF-κB）激活相关（Wu，S，Tan，M，Hu，Y，Wang，JL，Scheuner，D，Kaufman，RJ，紫外线通过对IκBα合成的翻译抑制激活NFκB。《生物化学杂志》，279，34898 - 34902，2004）。在UVC照射后4小时，MEF（A/A）细胞中COX-2的翻译效率高于MEF（S/S）细胞，但在24小时时并非如此。翻译效率与激活的COX-2结合蛋白HuR/TIAR的比例相关。此外，新合成的COX-2蛋白在MEF（A/A）细胞中比在MEF（S/S）细胞中更稳定。结果表明COX-2表达存在复杂且动态的调控。
意义
UVC诱导COX-2的长时间表达。虽然对COX-2表达的转录调控已进行了深入研究，但UVC照射后COX-2合成的翻译调控作用尚不清楚。本研究阐明了一个以eIF2α磷酸化为中心的新型网络，用于UVC照射后COX-2表达的调控。
Zotero 插件