Previous Article | Next Article ![]()
Molecular and Cellular Biology, November 2000, p. 8134-8142, Vol. 20, No. 21
Lehrstuhl für Allgemeine und Molekulare
Botanik, Ruhr-Universität Bochum, 44780 Bochum, Germany
Received 2 May 2000/Returned for modification 10 June 2000/Accepted 17 August 2000
Chloroplast translation is mediated by nucleus-encoded factors that
interact with distinct cis-acting RNA elements. A U-rich sequence within the 5' untranslated region of the psbD mRNA
has previously been shown to be required for its translation in
Chlamydomonas reinhardtii. By using UV cross-linking
assays, we have identified a 40-kDa RNA binding protein, which binds to
the wild-type psbD leader, but is unable to recognize a
nonfunctional leader mutant lacking the U-rich motif. RNA binding is
restored in a chloroplast cis-acting suppressor. The
functions of several site-directed psbD leader mutants were
analyzed with transgenic C. reinhardtii chloroplasts and
the in vitro RNA binding assay. A clear correlation between
photosynthetic activity and the capability to bind RNA by the 40-kDa
protein was observed. Furthermore, the data obtained suggest that the
poly(U) region serves as a molecular spacer between two previously
characterized cis-acting elements, which are involved in
RNA stabilization and translation. RNA-protein complex formation depends on the nuclear Nac2 gene product that is part of a
protein complex required for the stabilization of the psbD
mRNA. The sedimentation properties of the 40-kDa RNA binding protein
suggest that it interacts directly with this Nac2 complex and, as a
result, links processes of chloroplast RNA metabolism and translation.
0270-7306/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
cis- and trans-Acting
Determinants for Translation of psbD mRNA in
Chlamydomonas reinhardtii
*
Corresponding author. Mailing address: Lehrstuhl
für Allgemeine und Molekulare Botanik, Ruhr-Universität
Bochum, 44780 Bochum, Germany. Phone: 49 234 32 25539. Fax: 49 234 32 14184. E-mail: Joerg.Nickelsen{at}ruhr-uni-bochum.de.
This article has been cited by other articles:
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|