Reassessing the role of a 3'-UTR-binding translational inhibitor in regulation of circadian bioluminescence rhythm in the dinoflagellate Gonyaulax.
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.
Lapointe
Mathieu
M
Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, 4101 Sherbrooke Est, Montréal H1X 2B2, Québec, Canada.
Morse
David
D
D020413:3' Untranslated Regions / Q000276:immunology*; D000818:Animals; D001345:Autoradiography; D002940:Circadian Rhythm / Q000235:genetics*; D003432:Cross-Linking Reagents; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D004141:Dinoflagellida / Q000235:genetics*; D004591:Electrophoresis, Polyacrylamide Gel; D024202:Electrophoretic Mobility Shift Assay; D004926:Escherichia coli; D015723:Gene Library; D017403:In Situ Hybridization; D049449:Luminescence; D008164:Luminescent Proteins / Q000235:genetics; D046188:Protein Modification, Translational / Q000187:drug effects*; D012313:RNA / Q000096:biosynthesis / Q000235:genetics; D015347:RNA Probes; D012441:Saccharomyces cerevisiae / Q000235:genetics; D014466:Ultraviolet Rays
D020413:3' Untranslated Regions; D003432:Cross-Linking Reagents; D018076:DNA, Complementary; D008164:Luminescent Proteins; D015347:RNA Probes; D012313:RNA