Multiple translational control sequences in the 5' leader of the chloroplast psbC mRNA interact with nuclear gene products in Chlamydomonas reinhardtii.

Translation of the chloroplast psbC mRNA in the unicellular eukaryotic alga Chlamydomonas reinhardtii is controlled by interactions between its 547-base 5' untranslated region and the products of the nuclear loci TBC1, TBC2, and possibly TBC3. In this study, a series of site-directed mutations in this region was generated and the ability of these constructs to drive expression of a reporter gene was assayed in chloroplast transformants that are wild type or mutant at these nuclear loci. Two regions located in the middle of the 5' leader and near the initiation codon are important for translation. Other deletions still allow for partial expression of the reporter gene in the wild-type background. Regions with target sites for TBC1 and TBC2 were identified by estimating the residual translation activity in the respective mutant backgrounds. TBC1 targets include mostly the central part of the leader and the translation initiation region whereas the only detected TBC2 targets are in the 3' part. The 5'-most 93 nt of the leader are required for wild-type levels of transcription and/or mRNA stabilization. The results indicate that TBC1 and TBC2 function independently and further support the possibility that TBC1 acts together with TBC3.

[1]  W. Zerges.  Does complexity constrain organelle evolution? , 2002, Trends in plant science.

[2]  D. Esposito,et al.  A Role for Initiation Codon Context in Chloroplast Translation , 2001, The Plant Cell Online.

[3]  D. Drapier,et al.  Assembly-controlled regulation of chloroplast gene translation. , 2001, Biochemical Society transactions.

[4]  D. Fargo,et al.  Chloroplast Ribosomal Protein S7 of Chlamydomonas Binds to Chloroplast mRNA Leader Sequences and May Be Involved in Translation Initiation , 2001, Plant Cell.

[5]  W Zerges,et al.  Translation in chloroplasts. , 2000, Biochimie.

[6]  A. Barkan,et al.  Participation of nuclear genes in chloroplast gene expression. , 2000, Biochimie.

[7]  K. Kindle,et al.  Small cis-Acting Sequences That Specify Secondary Structures in a Chloroplast mRNA Are Essential for RNA Stability and Translation , 1999, Molecular and Cellular Biology.

[8]  D. Fargo,et al.  Mutations Altering the Predicted Secondary Structure of a Chloroplast 5′ Untranslated Region Affect Its Physical and Biochemical Properties as Well as Its Ability To Promote Translation of Reporter mRNAs Both in the Chlamydomonas reinhardtii Chloroplast and in Escherichia coli , 1999, Molecular and Cellular Biology.

[9]  Zou,et al.  In vivo analysis of plastid psbA, rbcL and rpl32 UTR elements by chloroplast transformation: tobacco plastid gene expression is controlled by modulation of transcript levels and translation efficiency , 1999, The Plant journal : for cell and molecular biology.

[10]  M. Kozak.  Initiation of translation in prokaryotes and eukaryotes. , 1999, Gene.

[11]  Masaru Tomita,et al.  Analysis of base-pairing potentials between 16S rRNA and 5' UTR for translation initiation in various prokaryotes , 1999, Bioinform..

[12]  J. Nickelsen,et al.  Identification of cis-Acting RNA Leader Elements Required for Chloroplast psbD Gene Expression in Chlamydomonas , 1999, Plant Cell.

[13]  Bruick,et al.  Light-activated translation of chloroplast mRNAs. , 1999, Trends in plant science.

[14]  G. Schuster,et al.  3′-Processed mRNA Is Preferentially Translated in Chlamydomonas reinhardtii Chloroplasts , 1998, Molecular and Cellular Biology.

[15]  S. Mayfield,et al.  Translation of the Chloroplast psbA mRNA Requires the Nuclear-encoded Poly(A)-binding Protein, RB47 , 1998, The Journal of cell biology.

[16]  D. Fargo,et al.  Shine-Dalgarno-like sequences are not required for translation of chloroplast mRNAs in Chlamydomonas reinhardtii chloroplasts or in Escherichia coli , 1998, Molecular and General Genetics MGG.

[17]  A. Danon.  Translational Regulation in the Chloroplast , 1997, Plant physiology.

[18]  J. Rochaix,et al.  Translation of the chloroplast psbC mRNA is controlled by interactions between its 5' leader and the nuclear loci TBC1 and TBC3 in Chlamydomonas reinhardtii , 1997, Molecular and cellular biology.

[19]  J. Rochaix,et al.  A nuclear-encoded function essential for translation of the chloroplast psaB mRNA in chlamydomonas. , 1997, The Plant cell.

[20]  P. Bennoun,et al.  Screening algal mutant colonies with altered thylakoid electrochemical gradient through fluorescence and delayed luminescence digital imaging , 1997, Photosynthesis Research.

[21]  J. Rochaix.  Post-transcriptional regulation of chloroplast gene expression in Chlamydomonas reinhardtii , 1996, Plant Molecular Biology.

[22]  S. Mayfield,et al.  Altered mRNA binding activity and decreased translational initiation in a nuclear mutant lacking translation of the chloroplast psbA mRNA , 1996, Molecular and cellular biology.

[23]  S. Mayfield,et al.  Translation of the psbA mRNA of Chlamydomonas reinhardtii requires a structured RNA element contained within the 5' untranslated region , 1994, The Journal of cell biology.

[24]  E. H. Harris,et al.  Chloroplast ribosomes and protein synthesis. , 1994, Microbiological reviews.

[25]  W. Sakamoto,et al.  Function of the Chlamydomonas reinhardtii petd 5' untranslated region in regulating the accumulation of subunit IV of the cytochrome b6/f complex. , 1994, The Plant journal : for cell and molecular biology.

[26]  J. Rochaix,et al.  The 5' leader of a chloroplast mRNA mediates the translational requirements for two nucleus-encoded functions in Chlamydomonas reinhardtii , 1994, Molecular and cellular biology.

[27]  J. Nickelsen,et al.  Determinants for stability of the chloroplast psbD RNA are located within its short leader region in Chlamydomonas reinhardtii. , 1994, The EMBO journal.

[28]  P. Maliga,et al.  Accumulation of D1 polypeptide in tobacco plastids is regulated via the untranslated region of the psbA mRNA. , 1993, The EMBO journal.

[29]  S. Leu,et al.  Complete DNA sequence of the Chlamydomonas reinhardtii chloroplast atpA gene , 1992, Plant Molecular Biology.

[30]  M. Goldschmidt-Clermont,et al.  Transgenic expression of aminoglycoside adenine transferase in the chloroplast: a selectable marker of site-directed transformation of chlamydomonas. , 1991, Nucleic acids research.

[31]  J. Rochaix,et al.  Trans-splicing mutants of Chlamydomonas reinhardtii , 1990, Molecular and General Genetics MGG.

[32]  J. Rochaix,et al.  Nuclear and chloroplast mutations affect the synthesis or stability of the chloroplast psbC gene product in Chlamydomonas reinhardtii. , 1989, The EMBO journal.

[33]  M. Rahire,et al.  Sequence, evolution and differential expression of the two genes encoding variant small subunits of ribulose bisphosphate carboxylase/oxygenase in Chlamydomonas reinhardtii. , 1986, Journal of molecular biology.

[34]  M. Rahire,et al.  Sequence of the chloroplast DNA region of Chlamydomonas reinhardii containing the gene of the large subunit of ribulose bisphosphate carboxylase and parts of its flanking genes. , 1982, Journal of molecular biology.

[35]  J. Rochaix.  Restriction endonuclease map of the chloroplast DNA of Chlamydomonas reinhardii. , 1978, Journal of molecular biology.

[36]  R. Levine,et al.  Cytochrome f and plastocyanin: their sequence in the photosynthetic electron transport chain of Chlamydomonas reinhardi. , 1965, Proceedings of the National Academy of Sciences of the United States of America.

[37]  M. Goldschmidt-Clermont.  Coordination of nuclear and chloroplast gene expression in plant cells. , 1998, International review of cytology.

[38]  M. Sugiura,et al.  Evolution and mechanism of translation in chloroplasts. , 1998, Annual review of genetics.

[39]  L. Gold,et al.  Posttranscriptional regulatory mechanisms in Escherichia coli. , 1988, Annual review of biochemistry.

[40]  N. W. Gillham,et al.  The sequence of the chloroplast atpB gene and its flanking regions in Chlamydomonas reinhardtii. , 1986, Gene.

[41]  R. Wu,et al.  4 – Exonuclease III: Use for DNA Sequence Analysis and in Specific Deletions of Nucleotides , 1983 .