FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W2061364145> ?p ?o ?g. }

• W2061364145 endingPage "3940" @default.
• W2061364145 startingPage "3937" @default.
• W2061364145 abstract "RNA editing is an important post-transcriptional process in chloroplasts and is thought to be functionally significant. Here we show a requirement of RNA editing for a functional enzyme. In peas, acetyl-CoA carboxylase (ACCase), a key enzyme of fatty acid synthesis, is composed of biotin carboxylase with the biotin carboxyl carrier protein and carboxyltransferase (CT). CT is composed of the nuclear-encoded α polypeptide and the chloroplast-encoded β polypeptide in peas. One nucleotide of the β polypeptide mRNA, which is edited in pea chloroplasts, converts the serine codon to the leucine codon. We show that this RNA editing is required for functional CT by comparing the unedited and edited recombinant enzymes. In plants not having a leucine codon at the same position, editing was shown to take place so as to create the leucine codon, indicating that editing is needed for in vivo CT activity and therefore for ACCase. To our knowledge, ACCase is an essential enzyme, suggesting that the chloroplast RNA editing is necessary for these plants. RNA editing is an important post-transcriptional process in chloroplasts and is thought to be functionally significant. Here we show a requirement of RNA editing for a functional enzyme. In peas, acetyl-CoA carboxylase (ACCase), a key enzyme of fatty acid synthesis, is composed of biotin carboxylase with the biotin carboxyl carrier protein and carboxyltransferase (CT). CT is composed of the nuclear-encoded α polypeptide and the chloroplast-encoded β polypeptide in peas. One nucleotide of the β polypeptide mRNA, which is edited in pea chloroplasts, converts the serine codon to the leucine codon. We show that this RNA editing is required for functional CT by comparing the unedited and edited recombinant enzymes. In plants not having a leucine codon at the same position, editing was shown to take place so as to create the leucine codon, indicating that editing is needed for in vivo CT activity and therefore for ACCase. To our knowledge, ACCase is an essential enzyme, suggesting that the chloroplast RNA editing is necessary for these plants. acetyl-CoA carboxylase carboxyltransferase polyacrylamide gel electrophoresis RNA editing is one of the most interesting and universal RNA-processing mechanisms known to affect gene regulation. This process has been detected in a variety of organisms, such as trypanosomes and viruses (1Benne R. Curr. Opin. Genet. Dev. 1996; 6: 221-231Crossref PubMed Scopus (42) Google Scholar, 2Maier R.M. Zeltz P. Kössel H. Bonnard G. Gualberto J.M. Grienenberger J.M. Plant Mol. Biol. 1996; 32: 343-365Crossref PubMed Scopus (165) Google Scholar). In mammalian systems, both edited and unedited proteins are functional and have distinct properties (3Chen S.-H. Habib G. Yang C.-Y. Gu Z.-W. Lee B.R. Weng S. Silberman S.R. Cai S.-J. Deslypere J.P. Rosseneu M. Gotto Jr., A.M. Li W-H. Chan L. Science. 1987; 238: 363-366Crossref PubMed Scopus (527) Google Scholar, 4Powell L.M. Wallis S.C. Pease R.J. Edwards Y.H. Knott T.J. Scott J. Cell. 1987; 50: 831-840Abstract Full Text PDF PubMed Scopus (710) Google Scholar, 5Hume R.I. Dingledine R. Heinemann S.F. Science. 1991; 253: 1028-1031Crossref PubMed Scopus (602) Google Scholar, 6Lomeli H. Mosbacher J. Melcher T. Höger T. Geiger J.R.P. Kuner T. Monyer H. Higuchi M. Bach A. Seeburg P.H. Science. 1994; 266: 1709-1713Crossref PubMed Scopus (636) Google Scholar). For example, the edited and unedited subunits of the glutamate receptor give rise to complex differing in calcium permeability (5Hume R.I. Dingledine R. Heinemann S.F. Science. 1991; 253: 1028-1031Crossref PubMed Scopus (602) Google Scholar). In chloroplasts, RNA editing is a widespread processing event, creating start and stop codons and most frequently altering coding sequences (7Hoch B. Maier R.M. Appel K. Igloi G.L. Kössel H. Nature. 1991; 353: 178-180Crossref PubMed Scopus (252) Google Scholar, 8Kudla J. Igloi G.L. Metzlaff M. Hagemann R. Kössel H. EMBO J. 1992; 11: 1099-1103Crossref PubMed Scopus (106) Google Scholar, 9Maier R.M. Hoch B. Zeltz P. Kössel H. Plant Cell. 1992; 4: 609-616PubMed Google Scholar, 10Wakasugi T. Hirose T. Horihata M. Tsudzuki T. Kössel H. Sugiura M. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 8766-8770Crossref PubMed Scopus (99) Google Scholar, 11Freyer R. Kiefer-Meyer M.-C. Kössel H. Proc. Natl. Acad. Sci. U. S. A. 1997; 94: 6285-6290Crossref PubMed Scopus (157) Google Scholar). To date, a number of RNA editing sites have been identified in chloroplasts with completely sequenced genomes, for example 26 sites in maize (12Maier R.M. Neckermann K. Igloi G.L. Kössel H. J. Mol. Biol. 1995; 251: 614-628Crossref PubMed Scopus (509) Google Scholar), 26 sites in black pine (10Wakasugi T. Hirose T. Horihata M. Tsudzuki T. Kössel H. Sugiura M. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 8766-8770Crossref PubMed Scopus (99) Google Scholar), and 31 sites in tobacco (13Hirose T. Kusumegi T. Tsudzuki T. Sugiura M. Mol. Gen. Genet. 1999; 262: 462-467Crossref PubMed Scopus (100) Google Scholar). The functional significance of the creation of an initiation codon and a stop codon is easily understood (7Hoch B. Maier R.M. Appel K. Igloi G.L. Kössel H. Nature. 1991; 353: 178-180Crossref PubMed Scopus (252) Google Scholar, 8Kudla J. Igloi G.L. Metzlaff M. Hagemann R. Kössel H. EMBO J. 1992; 11: 1099-1103Crossref PubMed Scopus (106) Google Scholar). Alteration of an internal codon results in the conservation of functionally important amino acids, suggesting that the conserved residues are critical for the function of the protein (9Maier R.M. Hoch B. Zeltz P. Kössel H. Plant Cell. 1992; 4: 609-616PubMed Google Scholar, 10Wakasugi T. Hirose T. Horihata M. Tsudzuki T. Kössel H. Sugiura M. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 8766-8770Crossref PubMed Scopus (99) Google Scholar, 11Freyer R. Kiefer-Meyer M.-C. Kössel H. Proc. Natl. Acad. Sci. U. S. A. 1997; 94: 6285-6290Crossref PubMed Scopus (157) Google Scholar, 12Maier R.M. Neckermann K. Igloi G.L. Kössel H. J. Mol. Biol. 1995; 251: 614-628Crossref PubMed Scopus (509) Google Scholar, 14Sugiura M. Hirose T. Sugita M. Annu. Rev. Genet. 1998; 32: 437-459Crossref PubMed Scopus (149) Google Scholar). However, we do not know whether both unedited and edited proteins are functional in chloroplasts and therefore whether chloroplast RNA editing is necessary.An in vitro approach will give some answers to these questions. Chloroplast-encoded polypeptides are mostly membrane proteins forming large complexes, and it is difficult to reconstitute such functional complexes using any in vitro approach. Several soluble complexes containing chloroplast-encoded polypeptides, such as ribulose-bisphosphate carboxylase, RNA polymerase, and ATP-dependent protease, have not yet been reconstitutedin vitro. Here we present the first biochemical evidence for the functional necessity of editing by using a reconstituted enzyme involved in fatty acid synthesis.Chloroplasts possess a key enzyme required for de novo fatty acid synthesis. This enzyme is the prokaryotic form of acetyl-CoA carboxylase (ACCase).1 The ACCase, different from the eukaryotic form of ACCase consisting of multimers of a single multifunctional polypeptide, is multienzyme complex composed of the biotin carboxylase complex and the carboxyltransferase (CT) enzyme (15Sasaki Y. Konishi T. Nagano Y. Plant Physiol. 1995; 108: 445-449Crossref PubMed Scopus (133) Google Scholar). The latter enzyme contains the nuclear-encoded α and the chloroplast-encoded β polypeptides (15Sasaki Y. Konishi T. Nagano Y. Plant Physiol. 1995; 108: 445-449Crossref PubMed Scopus (133) Google Scholar, 16Sasaki Y. Hakamada K. Suama Y. Nagano Y. Furusawa I. Matsuno R. J. Biol. Chem. 1993; 268: 25118-25123Abstract Full Text PDF PubMed Google Scholar, 17Ohlrogge J. Browse J. Plant Cell. 1995; 7: 957-970Crossref PubMed Scopus (1258) Google Scholar). We have recently reconstituted pea CT using a bicistronic plasmid in which the accA and accD cDNAs encoding the α and β polypeptides, respectively, were tandemly ligated to a decahistidine tag (His tag). We have also shown that the recombinant CT reconstituted in Escherichia coli has properties similar to those of authentic CT (18Kozaki A. Kamada K. Nagano Y. Iguchi H. Sasaki Y. J. Biol. Chem. 2000; 275: 10702-10708Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar). Because one nucleotide of an internal codon of pea accD mRNA is edited in chloroplasts (18Kozaki A. Kamada K. Nagano Y. Iguchi H. Sasaki Y. J. Biol. Chem. 2000; 275: 10702-10708Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar) and a serine codon is converted to a leucine codon, this reconstitution system provides a useful tool to examine whether this RNA editing is necessary for CT.Here we expressed in E. coli a construct containing the two DNAs encoding the accA mRNA and either the unedited or edited accD mRNA, and we measured the in vitro activities of the resultant unedited or edited CT. Activity was found in the edited CT, but not in the unedited CT, indicating that editing is necessary for a functional enzyme, and the leucine residue is critical in vitro. We found that editing at the same position took place in four plants not having leucine residues at the position, and we confirmed that editing is necessary for a functional protein in vivo.DISCUSSIONThe experiments reported here are the first demonstrations that chloroplast RNA editing is required for a functional ACCase, using two different approaches. One is the biochemical demonstration that the unedited recombinant enzyme is inactive in contrast to the edited enzyme. This means that editing is essential for in vitro enzyme activity. The second is the demonstration that chloroplast RNA editing takes place to create the leucine codon in all the examinedaccD gene not having leucine or its similar amino acid codon necessary for a functional enzyme. This suggests the necessity of RNA editing for a functional enzyme in vivo. We propose here that in plants RNA editing to create the leucine codon is essentialin vivo.The most frequently edited chloroplast RNAs are probably thendh transcripts encoding a putative chloroplast NADH dehydrogenase. For example, tobacco ndhA, ndhB, andndhD transcripts have been reported to have two, nine, and two editing sites, respectively (11Freyer R. Kiefer-Meyer M.-C. Kössel H. Proc. Natl. Acad. Sci. U. S. A. 1997; 94: 6285-6290Crossref PubMed Scopus (157) Google Scholar, 13Hirose T. Kusumegi T. Tsudzuki T. Sugiura M. Mol. Gen. Genet. 1999; 262: 462-467Crossref PubMed Scopus (100) Google Scholar). The extent of editing in thendhD transcript depends on developmental and environmental conditions (24Hirose T. Sugiura M. EMBO J. 1997; 16: 6804-6811Crossref PubMed Scopus (110) Google Scholar). These genes are shown to be dispensable for plant growth under mild environmental conditions (25Shikanai T. Endo T. Hashimoto T. Yamada Y. Asada K. Yokota A. Proc. Natl. Acad. Sci. U. S. A. 1998; 95: 9705-9709Crossref PubMed Scopus (351) Google Scholar, 26Burrows P.A. Sazanov L.A. Svab Z. Maliga P. Nixon P.J. EMBO J. 1998; 17: 868-876Crossref PubMed Scopus (396) Google Scholar), and the biological significance of RNA editing in ndh transcripts is not yet understood.A possible role of chloroplast RNA editing has been reported for the tobacco rpoA transcript encoding the α subunit of chloroplast-encoded RNA polymerase (13Hirose T. Kusumegi T. Tsudzuki T. Sugiura M. Mol. Gen. Genet. 1999; 262: 462-467Crossref PubMed Scopus (100) Google Scholar). This editing is believed to be involved in the regulation of RNA polymerase activity, because the extent of editing depends on developmental conditions. However, it is not known whether both the unedited and edited enzymes are functional. Further experiments are needed to characterize the biological significance.In contrast to ndh transcripts, the biological significance has been demonstrated for psbF (27Bock R. Kössel H. Maliga P. EMBO J. 1994; 13: 4623-4628Crossref PubMed Scopus (167) Google Scholar) encoding a core component of the photosystem II and for petB (28Zito R. Kuras R. Choquet Y. Kössel H. Wollman F.A. Plant Mol. Biol. 1997; 33: 79-86Crossref PubMed Scopus (66) Google Scholar) encoding a subunit of the cytochrome b 6 f complex. psbF is required for the functional photosystem II (29Pakrasi H.B. De Ciechi P. Whitmarsh J. EMBO J. 1991; 10: 1619-1627Crossref PubMed Scopus (76) Google Scholar). Spinach and tobacco psbF proteins are 100% identical, but only a nucleotide of the spinach transcript is edited. The introduction of spinach psbF into the tobacco plastid genome that lacks the capacity to edit the introduced site resulted in a mutant phenotype of slower growth, lowered chlorophyll content, and high chlorophyll fluorescence. This lack of editing resulted in reduced protein activity, but not a complete loss of function, indicating that this RNA editing is not essential for in vivo function.Chlamydomonas and maize petB proteins are 88% identical (94% similar). A codon at position 204 of thepetB gene is leucine in Chlamydomonas, but in maize it is proline, which is changed to a leucine by RNA editing. To examine a possible role of proline at the position 204, a proline codon was introduced in place of a leucine codon at position 204 of thepetB gene of Chlamydomonas. Chloroplast transcripts are not edited in Chlamydomonas. TheChlamydomonas transformants obtained were nonphototrophic mutant. They lacked photosynthetic electron transfer and cytochromeb 6 f activity, indicating that the proline is not fit for Chlamydomonas cytochromeb 6 f. This result strongly suggests that this RNA editing is essential for photosynthesis in maize.Plants have two forms of ACCase, the heteromeric, prokaryotic form composed of four subunits in chloroplasts, and the homomeric, eukaryotic form composed of a single polypeptide in cytosol, except for Gramineae, which lacks the accD gene (30Konishi T. Sasaki Y. Proc. Natl. Acad. Sci. U. S. A. 1994; 91: 3598-3601Crossref PubMed Scopus (190) Google Scholar, 31Konishi T. Shinohara K. Yamada K. Sasaki Y. Plant Cell Physiol. 1996; 37: 117-122Crossref PubMed Scopus (231) Google Scholar). Although rice has an accD gene remnant, wheat and maize do not have a counterpart to this. Gramineae does not have the prokaryotic form of ACCase in chloroplasts but has the nuclear-encoded eukaryotic form of ACCase in both chloroplasts and cytosol. Each ACCase supplies malonyl-CoA for the synthesis of fatty acids in chloroplasts or for the synthesis of flavonoid and the chain elongation of fatty acids in cytosol. To our knowledge no evidence exists that malonyl-CoA synthesized in cytosol enters into plastids. ACCase is necessary in chloroplasts for de novo fatty acid synthesis. Probably the prokaryotic form of ACCase is essential for plants. E. coli accD is an essential gene (32Nagano Y. Matsuno R. Sasaki Y. Mol. Gen. Genet. 1991; 228: 62-64Crossref PubMed Scopus (9) Google Scholar). Both accA andaccD are present as a single copy in Arabidopsis nuclear and chloroplast genomes, respectively, and are essential genes. Thus, chloroplast RNA editing is necessary not only for ACCase but also for the survival of these plants. RNA editing is one of the most interesting and universal RNA-processing mechanisms known to affect gene regulation. This process has been detected in a variety of organisms, such as trypanosomes and viruses (1Benne R. Curr. Opin. Genet. Dev. 1996; 6: 221-231Crossref PubMed Scopus (42) Google Scholar, 2Maier R.M. Zeltz P. Kössel H. Bonnard G. Gualberto J.M. Grienenberger J.M. Plant Mol. Biol. 1996; 32: 343-365Crossref PubMed Scopus (165) Google Scholar). In mammalian systems, both edited and unedited proteins are functional and have distinct properties (3Chen S.-H. Habib G. Yang C.-Y. Gu Z.-W. Lee B.R. Weng S. Silberman S.R. Cai S.-J. Deslypere J.P. Rosseneu M. Gotto Jr., A.M. Li W-H. Chan L. Science. 1987; 238: 363-366Crossref PubMed Scopus (527) Google Scholar, 4Powell L.M. Wallis S.C. Pease R.J. Edwards Y.H. Knott T.J. Scott J. Cell. 1987; 50: 831-840Abstract Full Text PDF PubMed Scopus (710) Google Scholar, 5Hume R.I. Dingledine R. Heinemann S.F. Science. 1991; 253: 1028-1031Crossref PubMed Scopus (602) Google Scholar, 6Lomeli H. Mosbacher J. Melcher T. Höger T. Geiger J.R.P. Kuner T. Monyer H. Higuchi M. Bach A. Seeburg P.H. Science. 1994; 266: 1709-1713Crossref PubMed Scopus (636) Google Scholar). For example, the edited and unedited subunits of the glutamate receptor give rise to complex differing in calcium permeability (5Hume R.I. Dingledine R. Heinemann S.F. Science. 1991; 253: 1028-1031Crossref PubMed Scopus (602) Google Scholar). In chloroplasts, RNA editing is a widespread processing event, creating start and stop codons and most frequently altering coding sequences (7Hoch B. Maier R.M. Appel K. Igloi G.L. Kössel H. Nature. 1991; 353: 178-180Crossref PubMed Scopus (252) Google Scholar, 8Kudla J. Igloi G.L. Metzlaff M. Hagemann R. Kössel H. EMBO J. 1992; 11: 1099-1103Crossref PubMed Scopus (106) Google Scholar, 9Maier R.M. Hoch B. Zeltz P. Kössel H. Plant Cell. 1992; 4: 609-616PubMed Google Scholar, 10Wakasugi T. Hirose T. Horihata M. Tsudzuki T. Kössel H. Sugiura M. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 8766-8770Crossref PubMed Scopus (99) Google Scholar, 11Freyer R. Kiefer-Meyer M.-C. Kössel H. Proc. Natl. Acad. Sci. U. S. A. 1997; 94: 6285-6290Crossref PubMed Scopus (157) Google Scholar). To date, a number of RNA editing sites have been identified in chloroplasts with completely sequenced genomes, for example 26 sites in maize (12Maier R.M. Neckermann K. Igloi G.L. Kössel H. J. Mol. Biol. 1995; 251: 614-628Crossref PubMed Scopus (509) Google Scholar), 26 sites in black pine (10Wakasugi T. Hirose T. Horihata M. Tsudzuki T. Kössel H. Sugiura M. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 8766-8770Crossref PubMed Scopus (99) Google Scholar), and 31 sites in tobacco (13Hirose T. Kusumegi T. Tsudzuki T. Sugiura M. Mol. Gen. Genet. 1999; 262: 462-467Crossref PubMed Scopus (100) Google Scholar). The functional significance of the creation of an initiation codon and a stop codon is easily understood (7Hoch B. Maier R.M. Appel K. Igloi G.L. Kössel H. Nature. 1991; 353: 178-180Crossref PubMed Scopus (252) Google Scholar, 8Kudla J. Igloi G.L. Metzlaff M. Hagemann R. Kössel H. EMBO J. 1992; 11: 1099-1103Crossref PubMed Scopus (106) Google Scholar). Alteration of an internal codon results in the conservation of functionally important amino acids, suggesting that the conserved residues are critical for the function of the protein (9Maier R.M. Hoch B. Zeltz P. Kössel H. Plant Cell. 1992; 4: 609-616PubMed Google Scholar, 10Wakasugi T. Hirose T. Horihata M. Tsudzuki T. Kössel H. Sugiura M. Proc. Natl. Acad. Sci. U. S. A. 1996; 93: 8766-8770Crossref PubMed Scopus (99) Google Scholar, 11Freyer R. Kiefer-Meyer M.-C. Kössel H. Proc. Natl. Acad. Sci. U. S. A. 1997; 94: 6285-6290Crossref PubMed Scopus (157) Google Scholar, 12Maier R.M. Neckermann K. Igloi G.L. Kössel H. J. Mol. Biol. 1995; 251: 614-628Crossref PubMed Scopus (509) Google Scholar, 14Sugiura M. Hirose T. Sugita M. Annu. Rev. Genet. 1998; 32: 437-459Crossref PubMed Scopus (149) Google Scholar). However, we do not know whether both unedited and edited proteins are functional in chloroplasts and therefore whether chloroplast RNA editing is necessary. An in vitro approach will give some answers to these questions. Chloroplast-encoded polypeptides are mostly membrane proteins forming large complexes, and it is difficult to reconstitute such functional complexes using any in vitro approach. Several soluble complexes containing chloroplast-encoded polypeptides, such as ribulose-bisphosphate carboxylase, RNA polymerase, and ATP-dependent protease, have not yet been reconstitutedin vitro. Here we present the first biochemical evidence for the functional necessity of editing by using a reconstituted enzyme involved in fatty acid synthesis. Chloroplasts possess a key enzyme required for de novo fatty acid synthesis. This enzyme is the prokaryotic form of acetyl-CoA carboxylase (ACCase).1 The ACCase, different from the eukaryotic form of ACCase consisting of multimers of a single multifunctional polypeptide, is multienzyme complex composed of the biotin carboxylase complex and the carboxyltransferase (CT) enzyme (15Sasaki Y. Konishi T. Nagano Y. Plant Physiol. 1995; 108: 445-449Crossref PubMed Scopus (133) Google Scholar). The latter enzyme contains the nuclear-encoded α and the chloroplast-encoded β polypeptides (15Sasaki Y. Konishi T. Nagano Y. Plant Physiol. 1995; 108: 445-449Crossref PubMed Scopus (133) Google Scholar, 16Sasaki Y. Hakamada K. Suama Y. Nagano Y. Furusawa I. Matsuno R. J. Biol. Chem. 1993; 268: 25118-25123Abstract Full Text PDF PubMed Google Scholar, 17Ohlrogge J. Browse J. Plant Cell. 1995; 7: 957-970Crossref PubMed Scopus (1258) Google Scholar). We have recently reconstituted pea CT using a bicistronic plasmid in which the accA and accD cDNAs encoding the α and β polypeptides, respectively, were tandemly ligated to a decahistidine tag (His tag). We have also shown that the recombinant CT reconstituted in Escherichia coli has properties similar to those of authentic CT (18Kozaki A. Kamada K. Nagano Y. Iguchi H. Sasaki Y. J. Biol. Chem. 2000; 275: 10702-10708Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar). Because one nucleotide of an internal codon of pea accD mRNA is edited in chloroplasts (18Kozaki A. Kamada K. Nagano Y. Iguchi H. Sasaki Y. J. Biol. Chem. 2000; 275: 10702-10708Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar) and a serine codon is converted to a leucine codon, this reconstitution system provides a useful tool to examine whether this RNA editing is necessary for CT. Here we expressed in E. coli a construct containing the two DNAs encoding the accA mRNA and either the unedited or edited accD mRNA, and we measured the in vitro activities of the resultant unedited or edited CT. Activity was found in the edited CT, but not in the unedited CT, indicating that editing is necessary for a functional enzyme, and the leucine residue is critical in vitro. We found that editing at the same position took place in four plants not having leucine residues at the position, and we confirmed that editing is necessary for a functional protein in vivo. DISCUSSIONThe experiments reported here are the first demonstrations that chloroplast RNA editing is required for a functional ACCase, using two different approaches. One is the biochemical demonstration that the unedited recombinant enzyme is inactive in contrast to the edited enzyme. This means that editing is essential for in vitro enzyme activity. The second is the demonstration that chloroplast RNA editing takes place to create the leucine codon in all the examinedaccD gene not having leucine or its similar amino acid codon necessary for a functional enzyme. This suggests the necessity of RNA editing for a functional enzyme in vivo. We propose here that in plants RNA editing to create the leucine codon is essentialin vivo.The most frequently edited chloroplast RNAs are probably thendh transcripts encoding a putative chloroplast NADH dehydrogenase. For example, tobacco ndhA, ndhB, andndhD transcripts have been reported to have two, nine, and two editing sites, respectively (11Freyer R. Kiefer-Meyer M.-C. Kössel H. Proc. Natl. Acad. Sci. U. S. A. 1997; 94: 6285-6290Crossref PubMed Scopus (157) Google Scholar, 13Hirose T. Kusumegi T. Tsudzuki T. Sugiura M. Mol. Gen. Genet. 1999; 262: 462-467Crossref PubMed Scopus (100) Google Scholar). The extent of editing in thendhD transcript depends on developmental and environmental conditions (24Hirose T. Sugiura M. EMBO J. 1997; 16: 6804-6811Crossref PubMed Scopus (110) Google Scholar). These genes are shown to be dispensable for plant growth under mild environmental conditions (25Shikanai T. Endo T. Hashimoto T. Yamada Y. Asada K. Yokota A. Proc. Natl. Acad. Sci. U. S. A. 1998; 95: 9705-9709Crossref PubMed Scopus (351) Google Scholar, 26Burrows P.A. Sazanov L.A. Svab Z. Maliga P. Nixon P.J. EMBO J. 1998; 17: 868-876Crossref PubMed Scopus (396) Google Scholar), and the biological significance of RNA editing in ndh transcripts is not yet understood.A possible role of chloroplast RNA editing has been reported for the tobacco rpoA transcript encoding the α subunit of chloroplast-encoded RNA polymerase (13Hirose T. Kusumegi T. Tsudzuki T. Sugiura M. Mol. Gen. Genet. 1999; 262: 462-467Crossref PubMed Scopus (100) Google Scholar). This editing is believed to be involved in the regulation of RNA polymerase activity, because the extent of editing depends on developmental conditions. However, it is not known whether both the unedited and edited enzymes are functional. Further experiments are needed to characterize the biological significance.In contrast to ndh transcripts, the biological significance has been demonstrated for psbF (27Bock R. Kössel H. Maliga P. EMBO J. 1994; 13: 4623-4628Crossref PubMed Scopus (167) Google Scholar) encoding a core component of the photosystem II and for petB (28Zito R. Kuras R. Choquet Y. Kössel H. Wollman F.A. Plant Mol. Biol. 1997; 33: 79-86Crossref PubMed Scopus (66) Google Scholar) encoding a subunit of the cytochrome b 6 f complex. psbF is required for the functional photosystem II (29Pakrasi H.B. De Ciechi P. Whitmarsh J. EMBO J. 1991; 10: 1619-1627Crossref PubMed Scopus (76) Google Scholar). Spinach and tobacco psbF proteins are 100% identical, but only a nucleotide of the spinach transcript is edited. The introduction of spinach psbF into the tobacco plastid genome that lacks the capacity to edit the introduced site resulted in a mutant phenotype of slower growth, lowered chlorophyll content, and high chlorophyll fluorescence. This lack of editing resulted in reduced protein activity, but not a complete loss of function, indicating that this RNA editing is not essential for in vivo function.Chlamydomonas and maize petB proteins are 88% identical (94% similar). A codon at position 204 of thepetB gene is leucine in Chlamydomonas, but in maize it is proline, which is changed to a leucine by RNA editing. To examine a possible role of proline at the position 204, a proline codon was introduced in place of a leucine codon at position 204 of thepetB gene of Chlamydomonas. Chloroplast transcripts are not edited in Chlamydomonas. TheChlamydomonas transformants obtained were nonphototrophic mutant. They lacked photosynthetic electron transfer and cytochromeb 6 f activity, indicating that the proline is not fit for Chlamydomonas cytochromeb 6 f. This result strongly suggests that this RNA editing is essential for photosynthesis in maize.Plants have two forms of ACCase, the heteromeric, prokaryotic form composed of four subunits in chloroplasts, and the homomeric, eukaryotic form composed of a single polypeptide in cytosol, except for Gramineae, which lacks the accD gene (30Konishi T. Sasaki Y. Proc. Natl. Acad. Sci. U. S. A. 1994; 91: 3598-3601Crossref PubMed Scopus (190) Google Scholar, 31Konishi T. Shinohara K. Yamada K. Sasaki Y. Plant Cell Physiol. 1996; 37: 117-122Crossref PubMed Scopus (231) Google Scholar). Although rice has an accD gene remnant, wheat and maize do not have a counterpart to this. Gramineae does not have the prokaryotic form of ACCase in chloroplasts but has the nuclear-encoded eukaryotic form of ACCase in both chloroplasts and cytosol. Each ACCase supplies malonyl-CoA for the synthesis of fatty acids in chloroplasts or for the synthesis of flavonoid and the chain elongation of fatty acids in cytosol. To our knowledge no evidence exists that malonyl-CoA synthesized in cytosol enters into plastids. ACCase is necessary in chloroplasts for de novo fatty acid synthesis. Probably the prokaryotic form of ACCase is essential for plants. E. coli accD is an essential gene (32Nagano Y. Matsuno R. Sasaki Y. Mol. Gen. Genet. 1991; 228: 62-64Crossref PubMed Scopus (9) Google Scholar). Both accA andaccD are present as a single copy in Arabidopsis nuclear and chloroplast genomes, respectively, and are essential genes. Thus, chloroplast RNA editing is necessary not only for ACCase but also for the survival of these plants. The experiments reported here are the first demonstrations that chloroplast RNA editing is required for a functional ACCase, using two different approaches. One is the biochemical demonstration that the unedited recombinant enzyme is inactive in contrast to the edited enzyme. This means that editing is essential for in vitro enzyme activity. The second is the demonstration that chloroplast RNA editing takes place to create the leucine codon in all the examinedaccD gene not having leucine or its similar amino acid codon necessary for a functional enzyme. This suggests the necessity of RNA editing for a functional enzyme in vivo. We propose here that in plants RNA editing to create the leucine codon is essentialin vivo. The most frequently edited chloroplast RNAs are probably thendh transcripts encoding a putative chloroplast NADH dehydrogenase. For example, tobacco ndhA, ndhB, andndhD transcripts have been reported to have two, nine, and two editing sites, respectively (11Freyer R. Kiefer-Meyer M.-C. Kössel H. Proc. Natl. Acad. Sci. U. S. A. 1997; 94: 6285-6290Crossref PubMed Scopus (157) Google Scholar, 13Hirose T. Kusumegi T. Tsudzuki T. Sugiura M. Mol. Gen. Genet. 1999; 262: 462-467Crossref PubMed Scopus (100) Google Scholar). The extent of editing in thendhD transcript depends on developmental and environmental conditions (24Hirose T. Sugiura M. EMBO J. 1997; 16: 6804-6811Crossref PubMed Scopus (110) Google Scholar). These genes are shown to be dispensable for plant growth under mild environmental conditions (25Shikanai T. Endo T. Hashimoto T. Yamada Y. Asada K. Yokota A. Proc. Natl. Acad. Sci. U. S. A. 1998; 95: 9705-9709Crossref PubMed Scopus (351) Google Scholar, 26Burrows P.A. Sazanov L.A. Svab Z. Maliga P. Nixon P.J. EMBO J. 1998; 17: 868-876Crossref PubMed Scopus (396) Google Scholar), and the biological significance of RNA editing in ndh transcripts is not yet understood. A possible role of chloroplast RNA editing has been reported for the tobacco rpoA transcript encoding the α subunit of chloroplast-encoded RNA polymerase (13Hirose T. Kusumegi T. Tsudzuki T. Sugiura M. Mol. Gen. Genet. 1999; 262: 462-467Crossref PubMed Scopus (100) Google Scholar). This editing is believed to be involved in the regulation of RNA polymerase activity, because the extent of editing depends on developmental conditions. However, it is not known whether both the unedited and edited enzymes are functional. Further experiments are needed to characterize the biological significance. In contrast to ndh transcripts, the biological significance has been demonstrated for psbF (27Bock R. Kössel H. Maliga P. EMBO J. 1994; 13: 4623-4628Crossref PubMed Scopus (167) Google Scholar) encoding a core component of the photosystem II and for petB (28Zito R. Kuras R. Choquet Y. Kössel H. Wollman F.A. Plant Mol. Biol. 1997; 33: 79-86Crossref PubMed Scopus (66) Google Scholar) encoding a subunit of the cytochrome b 6 f complex. psbF is required for the functional photosystem II (29Pakrasi H.B. De Ciechi P. Whitmarsh J. EMBO J. 1991; 10: 1619-1627Crossref PubMed Scopus (76) Google Scholar). Spinach and tobacco psbF proteins are 100% identical, but only a nucleotide of the spinach transcript is edited. The introduction of spinach psbF into the tobacco plastid genome that lacks the capacity to edit the introduced site resulted in a mutant phenotype of slower growth, lowered chlorophyll content, and high chlorophyll fluorescence. This lack of editing resulted in reduced protein activity, but not a complete loss of function, indicating that this RNA editing is not essential for in vivo function.Chlamydomonas and maize petB proteins are 88% identical (94% similar). A codon at position 204 of thepetB gene is leucine in Chlamydomonas, but in maize it is proline, which is changed to a leucine by RNA editing. To examine a possible role of proline at the position 204, a proline codon was introduced in place of a leucine codon at position 204 of thepetB gene of Chlamydomonas. Chloroplast transcripts are not edited in Chlamydomonas. TheChlamydomonas transformants obtained were nonphototrophic mutant. They lacked photosynthetic electron transfer and cytochromeb 6 f activity, indicating that the proline is not fit for Chlamydomonas cytochromeb 6 f. This result strongly suggests that this RNA editing is essential for photosynthesis in maize. Plants have two forms of ACCase, the heteromeric, prokaryotic form composed of four subunits in chloroplasts, and the homomeric, eukaryotic form composed of a single polypeptide in cytosol, except for Gramineae, which lacks the accD gene (30Konishi T. Sasaki Y. Proc. Natl. Acad. Sci. U. S. A. 1994; 91: 3598-3601Crossref PubMed Scopus (190) Google Scholar, 31Konishi T. Shinohara K. Yamada K. Sasaki Y. Plant Cell Physiol. 1996; 37: 117-122Crossref PubMed Scopus (231) Google Scholar). Although rice has an accD gene remnant, wheat and maize do not have a counterpart to this. Gramineae does not have the prokaryotic form of ACCase in chloroplasts but has the nuclear-encoded eukaryotic form of ACCase in both chloroplasts and cytosol. Each ACCase supplies malonyl-CoA for the synthesis of fatty acids in chloroplasts or for the synthesis of flavonoid and the chain elongation of fatty acids in cytosol. To our knowledge no evidence exists that malonyl-CoA synthesized in cytosol enters into plastids. ACCase is necessary in chloroplasts for de novo fatty acid synthesis. Probably the prokaryotic form of ACCase is essential for plants. E. coli accD is an essential gene (32Nagano Y. Matsuno R. Sasaki Y. Mol. Gen. Genet. 1991; 228: 62-64Crossref PubMed Scopus (9) Google Scholar). Both accA andaccD are present as a single copy in Arabidopsis nuclear and chloroplast genomes, respectively, and are essential genes. Thus, chloroplast RNA editing is necessary not only for ACCase but also for the survival of these plants. We thank K. Shinohara for his contribution of black pine seeds and J. H. Weil for discussion." @default.
• W2061364145 created "2016-06-24" @default.
• W2061364145 creator A5001198917 @default.
• W2061364145 creator A5019827800 @default.
• W2061364145 creator A5042790388 @default.
• W2061364145 creator A5080512568 @default.
• W2061364145 creator A5086661838 @default.
• W2061364145 date "2001-02-01" @default.
• W2061364145 modified "2023-10-14" @default.
• W2061364145 title "Chloroplast RNA Editing Required for Functional Acetyl-CoA Carboxylase in Plants" @default.
• W2061364145 cites W1216179325 @default.
• W2061364145 cites W1556152083 @default.
• W2061364145 cites W1574772208 @default.
• W2061364145 cites W1966933803 @default.
• W2061364145 cites W1976824685 @default.
• W2061364145 cites W1985012667 @default.
• W2061364145 cites W1986923087 @default.
• W2061364145 cites W2017807226 @default.
• W2061364145 cites W2036869066 @default.
• W2061364145 cites W2051072273 @default.
• W2061364145 cites W2051077808 @default.
• W2061364145 cites W2058336694 @default.
• W2061364145 cites W2065717544 @default.
• W2061364145 cites W2073646580 @default.
• W2061364145 cites W2079663310 @default.
• W2061364145 cites W2086932197 @default.
• W2061364145 cites W2088997851 @default.
• W2061364145 cites W2090872672 @default.
• W2061364145 cites W2096078781 @default.
• W2061364145 cites W2106882534 @default.
• W2061364145 cites W2106896768 @default.
• W2061364145 cites W2107544165 @default.
• W2061364145 cites W2122484406 @default.
• W2061364145 cites W2140244239 @default.
• W2061364145 cites W2147680318 @default.
• W2061364145 cites W2157815953 @default.
• W2061364145 cites W2160869622 @default.
• W2061364145 cites W2170151925 @default.
• W2061364145 cites W2294352457 @default.
• W2061364145 cites W2343989023 @default.
• W2061364145 doi "https://doi.org/10.1074/jbc.m008166200" @default.
• W2061364145 hasPubMedId "https://pubmed.ncbi.nlm.nih.gov/11078738" @default.
• W2061364145 hasPublicationYear "2001" @default.
• W2061364145 type Work @default.
• W2061364145 sameAs 2061364145 @default.
• W2061364145 citedByCount "73" @default.
• W2061364145 countsByYear W20613641452012 @default.
• W2061364145 countsByYear W20613641452013 @default.
• W2061364145 countsByYear W20613641452016 @default.
• W2061364145 countsByYear W20613641452017 @default.
• W2061364145 countsByYear W20613641452018 @default.
• W2061364145 countsByYear W20613641452019 @default.
• W2061364145 countsByYear W20613641452020 @default.
• W2061364145 countsByYear W20613641452021 @default.
• W2061364145 countsByYear W20613641452022 @default.
• W2061364145 countsByYear W20613641452023 @default.
• W2061364145 crossrefType "journal-article" @default.
• W2061364145 hasAuthorship W2061364145A5001198917 @default.
• W2061364145 hasAuthorship W2061364145A5019827800 @default.
• W2061364145 hasAuthorship W2061364145A5042790388 @default.
• W2061364145 hasAuthorship W2061364145A5080512568 @default.
• W2061364145 hasAuthorship W2061364145A5086661838 @default.
• W2061364145 hasBestOaLocation W20613641451 @default.
• W2061364145 hasConcept C104317684 @default.
• W2061364145 hasConcept C140137476 @default.
• W2061364145 hasConcept C181199279 @default.
• W2061364145 hasConcept C185592680 @default.
• W2061364145 hasConcept C21786251 @default.
• W2061364145 hasConcept C2779318131 @default.
• W2061364145 hasConcept C55493867 @default.
• W2061364145 hasConcept C67705224 @default.
• W2061364145 hasConcept C69305403 @default.
• W2061364145 hasConcept C70721500 @default.
• W2061364145 hasConcept C86803240 @default.
• W2061364145 hasConceptScore W2061364145C104317684 @default.
• W2061364145 hasConceptScore W2061364145C140137476 @default.
• W2061364145 hasConceptScore W2061364145C181199279 @default.
• W2061364145 hasConceptScore W2061364145C185592680 @default.
• W2061364145 hasConceptScore W2061364145C21786251 @default.
• W2061364145 hasConceptScore W2061364145C2779318131 @default.
• W2061364145 hasConceptScore W2061364145C55493867 @default.
• W2061364145 hasConceptScore W2061364145C67705224 @default.
• W2061364145 hasConceptScore W2061364145C69305403 @default.
• W2061364145 hasConceptScore W2061364145C70721500 @default.
• W2061364145 hasConceptScore W2061364145C86803240 @default.
• W2061364145 hasIssue "6" @default.
• W2061364145 hasLocation W20613641451 @default.
• W2061364145 hasOpenAccess W2061364145 @default.
• W2061364145 hasPrimaryLocation W20613641451 @default.
• W2061364145 hasRelatedWork W157595740 @default.
• W2061364145 hasRelatedWork W1982621198 @default.
• W2061364145 hasRelatedWork W2004392099 @default.
• W2061364145 hasRelatedWork W2033557727 @default.
• W2061364145 hasRelatedWork W2038752853 @default.
• W2061364145 hasRelatedWork W2061364145 @default.
• W2061364145 hasRelatedWork W2062656152 @default.
• W2061364145 hasRelatedWork W2098576269 @default.
• W2061364145 hasRelatedWork W2318910253 @default.

• next