Lapointe Mathieu, Morse David
Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, 4101 Sherbrooke Est, Montréal H1X 2B2, Québec, Canada.
Biol Chem. 2008 Jan;389(1):13-9. doi: 10.1515/BC.2008.003.
The nightly bioluminescence of the dinoflagellate Gonyaulax is a circadian rhythm caused by the presence in cells of specialized bioluminescent organelles, termed scintillons, containing the reaction catalyst luciferase, the substrate luciferin and a luciferin-binding protein (LBP). LBP levels increase at the start of the night phase because of increased protein synthesis rates in vivo, and this regulation has been ascribed to circadian binding of an inhibitory protein factor binding to the 3' untranslated region (UTR) of lbp mRNA at times when LBP is not normally synthesized. To purify and characterize the binding factor, the electrophoretic mobility shift assays and UV crosslinking experiments used to first characterize the factor were repeated. However, neither these protocols nor binding to biotinylated RNA probes confirmed the presence of a specific circadian RNA-binding protein. Furthermore, neither RNA probe screening of a cDNA library expressed in bacteria nor three-hybrid assays in yeast were successful in isolating a cDNA encoding a protein able to bind specifically to the lbp 3'UTR. Taken together, these results suggest that alternative mechanisms for regulating lbp translation should now be examined.
腰鞭毛虫（裸甲藻）的夜间生物发光是一种昼夜节律，由细胞中特殊的生物发光细胞器引起，这些细胞器称为闪烁体，含有反应催化剂荧光素酶、底物荧光素和荧光素结合蛋白（LBP）。由于体内蛋白质合成速率增加，LBP水平在夜间阶段开始时升高，这种调节归因于在LBP正常不合成时，一种抑制性蛋白质因子与lbp mRNA的3'非翻译区（UTR）的昼夜结合。为了纯化和表征结合因子，重复了最初用于表征该因子的电泳迁移率变动分析和紫外线交联实验。然而，这些方案以及与生物素化RNA探针的结合都未证实存在特定的昼夜节律RNA结合蛋白。此外，对细菌中表达的cDNA文库进行RNA探针筛选以及在酵母中进行三杂交分析，均未成功分离出编码能够特异性结合lbp 3'UTR的蛋白质的cDNA。综上所述，这些结果表明现在应该研究调节lbp翻译的替代机制。
