title: Synthesis and translation site of light-induced mRNAs in etiolated Euglena gracilis.
abstract: Poly(a)-mRNA synthesis has been studied in etiolated Euglena gracilis exposed to 1 or 2 h of illumination. 1. Labeling kinetics of mRNAs containing poly(A) sequences, during illumination or after return to darkness, reach a plateau in 10 or 20 min according to nutritional conditions. When the cultures are returned to darkness, the mRNA synthesis decreases rapidly. Thus, the synthesis of these mRNAs (light-induced mRNAs) is dependent on light and their half-life can be evaluated. 2. Cycloheximide induces accumulation of label in poly(A)-containing mRNA; such an accumulation is not observed after addition of lincomycin. Labeling during illumination of mRNA in a chloroplast mutant is similar to that in the wild type strain. These data suggest that the poly(A)-mRNAs synthesized in the two first hours of illumination are translated on cytoplasmic polyribosomes.
mesh_terms: D000818:Animals; D001483:Base Sequence; D003513:Cycloheximide / Q000494:pharmacology; D003624:Darkness; D005056:Euglena gracilis / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008027:Light; D008034:Lincomycin / Q000494:pharmacology; D011061:Poly A / Q000032:analysis; D012333:RNA, Messenger / Q000096:biosynthesis*; D012335:RNA, Ribosomal / Q000096:biosynthesis; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D012333:RNA, Messenger; D012335:RNA, Ribosomal; D011061:Poly A; D003513:Cycloheximide; D008034:Lincomycin