Journal Article

Dual targeting of the tRNA nucleotidyltransferase in plants: not just the signal

Serena Schmidt von Braun, Antonino Sabetti, Pamela J. Hanic-Joyce, Jun Gu, Enrico Schleiff and Paul B. M. Joyce

in Journal of Experimental Botany

Published on behalf of Society for Experimental Biology

Volume 58, issue 15-16, pages 4083-4093
Published in print December 2007 | ISSN: 0022-0957
Published online December 2007 | e-ISSN: 1460-2431 | DOI: http://dx.doi.org/10.1093/jxb/erm267

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Enzymes involved in tRNA maturation are essential for cytosolic, mitochondrial, and plastid protein synthesis and are therefore localized to these different compartments of the cell. Interestingly, only one isoform of tRNA nucleotidyltransferase (responsible for adding the 3′-terminal cytidine–cytidine–adenosine to tRNAs) has been identified in plants. The present study therefore explored how signals contained on this enzyme allow it to be distributed among the different cell compartments. It is demonstrated that the N-terminal portion of the protein acts as an organellar targeting signal and that differential use of multiple in-frame start codons alters the localization of the protein. Moreover, it is shown that the mature domain has a major impact on the distribution of the protein within the cell. These data indicate that regulation of dual localization involves not only specific N-terminal signals, but also additional factors within the protein or the cell.

Keywords: Dual targeting; plant protein distribution; targeting signal; tRNA nucleotidyltransferase

Journal Article.  6425 words.  Illustrated.

Subjects: Plant Sciences and Forestry

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