Photo- and Metabolite Regulation of the Synthesis of Ribulose Bisphosphate Carboxylase/Oxygenase and the Phycobiliproteins in the Alga Cyanidium caldarium.
In the eukaryotic and unicellular alga Cyanidium caldarium the synthesis of the plastid enzyme ribulose bisphosphate carboxylase/oxygenase (RuBPCase) and the light gathering proteins phycocyanin (PC) and allophycocyanin (APC) is under the control of light and glucose, which is a metabolizable carbon source for this organism. Light promotes the synthesis of these proteins while glucose has a strong inhibitory effect on this process. All subunits of the proteins mentioned above are in vitro translation products of poly (A)(-)-RNA (Steinmüller, Kaling, Zetsche 1983 Planta 159: 308-313). Both factors-light and glucose-exert their effects mainly by modulation of the level of translatable messenger RNA for these proteins. Under autotrophic growth conditions the level of translatable RuBPCase-, PC-, and APC-messenger RNA is high, whereas in the presence of glucose the level of these mRNAs is low or not detectable at all.
Steinmüller
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Institut für Pflanzenphysiologie der Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 54-62, D-6300 Giessen, Federal Republic of Germany.
Zetsche
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