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The Sites of Transcription and Translation for Euglena Chloroplastic Aminoacyl-tRNA Synthetases
L. I. Hecker, J. Egan, R. J. Reynolds, C. E. Nix, J. A. Schiff and W. Edgar Barnett
Proceedings of the National Academy of Sciences of the United States of America
Vol. 71, No. 5 (May, 1974), pp. 1910-1914
Published by: National Academy of Sciences
Stable URL: http://www.jstor.org/stable/63551
Page Count: 5
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We find that cycloheximide completely blocks the light-induced appearance of Euglena chloroplastic aminoacyl-tRNA synthetases in dark-grown cells of Euglena gracilis var. bacillaris. Streptomycin, on the other hand, has no effect on the light-induction of these organellar enzymes. These observations, together with the finding that an aplastidic mutant (strain W3BUL, which has neither significant plastid structure nor detectable chloroplast DNA) contains low levels of the chloroplastic synthetases, indicate that the chloroplastic synthetases are transcriptional products of nuclear genes and are translated on cytoplasmic ribosomes prior to compartmentalization within the chloroplasts.
Proceedings of the National Academy of Sciences of the United States of America © 1974 National Academy of Sciences