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Bock R. Strategies for metabolic pathway engineering with multiple transgenes. PLANT MOLECULAR BIOLOGY 2013; 83:21-31. [PMID: 23504453 DOI: 10.1007/s11103-013-0045-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 03/11/2013] [Indexed: 05/21/2023]
Abstract
The engineering of metabolic pathways in plants often requires the concerted expression of more than one gene. While with traditional transgenic approaches, the expression of multiple transgenes has been challenging, recent progress has greatly expanded our repertoire of powerful techniques making this possible. New technological options include large-scale co-transformation of the nuclear genome, also referred to as combinatorial transformation, and transformation of the chloroplast genome with synthetic operon constructs. This review describes the state of the art in multigene genetic engineering of plants. It focuses on the methods currently available for the introduction of multiple transgenes into plants and the molecular mechanisms underlying successful transgene expression. Selected examples of metabolic pathway engineering are used to illustrate the attractions and limitations of each method and to highlight key factors that influence the experimenter's choice of the best strategy for multigene engineering.
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Affiliation(s)
- Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany.
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Lu Y, Rijzaani H, Karcher D, Ruf S, Bock R. Efficient metabolic pathway engineering in transgenic tobacco and tomato plastids with synthetic multigene operons. Proc Natl Acad Sci U S A 2013; 110:E623-32. [PMID: 23382222 PMCID: PMC3581966 DOI: 10.1073/pnas.1216898110] [Citation(s) in RCA: 147] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The engineering of complex metabolic pathways requires the concerted expression of multiple genes. In plastids (chloroplasts) of plant cells, genes are organized in operons that are coexpressed as polycistronic transcripts and then often are processed further into monocistronic mRNAs. Here we have used the tocochromanol pathway (providing tocopherols and tocotrienols, collectively also referred to as "vitamin E") as an example to establish principles of successful multigene engineering by stable transformation of the chloroplast genome, a technology not afflicted with epigenetic variation and/or instability of transgene expression. Testing a series of single-gene constructs (encoding homogentisate phytyltransferase, tocopherol cyclase, and γ-tocopherol methyltransferase) and rationally designed synthetic operons in tobacco and tomato plants, we (i) confirmed previous results suggesting homogentisate phytyltransferase as the limiting enzymatic step in the pathway, (ii) comparatively characterized the bottlenecks in tocopherol biosynthesis in transplastomic leaves and tomato fruits, and (iii) achieved an up to tenfold increase in total tocochromanol accumulation. In addition, our results uncovered an unexpected light-dependent regulatory link between tocochromanol metabolism and the pathways of photosynthetic pigment biosynthesis. The synthetic operon design developed here will facilitate future synthetic biology applications in plastids, especially the design of artificial operons that introduce novel biochemical pathways into plants.
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Affiliation(s)
- Yinghong Lu
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany
| | | | - Daniel Karcher
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany
| | - Stephanie Ruf
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany
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Extreme conservation of the psaA/psaB intercistronic spacer reveals a translational motif coincident with the evolution of land plants. J Mol Evol 2012. [PMID: 23192453 DOI: 10.1007/s00239-012-9526-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Although chloroplast transcriptional and translational mechanisms were derived originally from prokaryote endosymbionts, chloroplasts retain comparatively few genes as a consequence of the overall transfer to the nucleus of functions associated formerly with prokaryotic genomes. Various modifications reflect other evolutionary shifts toward eukaryotic regulation such as posttranscriptional transcript cleavage with individually processed cistrons in operons and gene expression regulated by nuclear-encoded sigma factors. We report a notable exception for the psaA-psaB-rps14 operon of land plant (embryophyte) chloroplasts, where the first two cistrons are separated by a spacer region to which no significant role had been attributed. We infer an important function of this region, as indicated by the conservation of identical, structurally significant sequences across embryophytes and their ancestral protist lineages, which diverged some 0.5 billion years ago. The psaA/psaB spacers of embryophytes and their progenitors exhibit few sequence and length variants, with most modeled transcripts resolving the same secondary structure: a loop with projecting Shine-Dalgarno site and well-defined stem that interacts with adjacent coding regions to sequester the psaB start codon. Although many functions of the original endosymbiont have been usurped by nuclear genes or interactions, conserved functional elements of embryophyte psaA/psaB spacers provide compelling evidence that translation of psaB is regulated here by a cis-acting mechanism comparable to those common in prokaryotes. Modeled transcripts also indicate that spacer variants in some plants (e.g., aquatic genus Najas) potentially reflect ecological adaptations to facilitate temperature-regulated translation of psaB.
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Drechsel O, Bock R. Selection of Shine-Dalgarno sequences in plastids. Nucleic Acids Res 2011; 39:1427-38. [PMID: 20965967 PMCID: PMC3045613 DOI: 10.1093/nar/gkq978] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Revised: 09/16/2010] [Accepted: 10/04/2010] [Indexed: 11/29/2022] Open
Abstract
Like bacterial genes, most plastid (chloroplast) genes are arranged in operons and transcribed as polycistronic mRNAs. Plastid protein biosynthesis occurs on bacterial-type 70S ribosomes and translation initiation of many (but not all) mRNAs is mediated by Shine-Dalgarno (SD) sequences. To study the mechanisms of SD sequence recognition, we have analyzed translation initiation from mRNAs containing multiple SD sequences. Comparing translational efficiencies of identical transgenic mRNAs in Escherichia coli and plastids, we find surprising differences between the two systems. Most importantly, while internal SD sequences are efficiently recognized in E. coli, plastids exhibit a bias toward utilizing predominantly the 5'-most SD sequence. We propose that inefficient recognition of internal SD sequences provides the raison d'être for most plastid polycistronic transcripts undergoing post-transcriptional cleavage into monocistronic mRNAs.
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Affiliation(s)
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
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Walter M, Piepenburg K, Schöttler MA, Petersen K, Kahlau S, Tiller N, Drechsel O, Weingartner M, Kudla J, Bock R. Knockout of the plastid RNase E leads to defective RNA processing and chloroplast ribosome deficiency. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 64:851-63. [PMID: 21105931 DOI: 10.1111/j.1365-313x.2010.04377.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Ribonuclease E (RNase E) represents a key enzyme in bacterial RNA metabolism. It plays multifarious roles in RNA processing and also initiates degradation of mRNA by endonucleolytic cleavage. Plastids (chloroplasts) are derived from formerly free-living bacteria and have largely retained eubacterial gene expression mechanisms. Here we report the functional characterization of a chloroplast RNase E that is encoded by a single-copy nuclear gene in the model plant Arabidopsis thaliana. Analysis of knockout plants revealed that, unlike in bacteria, RNase E is not essential for survival. Absence of RNase E results in multiple defects in chloroplast RNA metabolism. Most importantly, polycistronic precursor transcripts overaccumulate in the knockout plants, while several mature monocistronic mRNAs are strongly reduced, suggesting an important function of RNase E in intercistronic processing of primary transcripts from chloroplast operons. We further show that disturbed maturation of a transcript encoding essential ribosomal proteins results in plastid ribosome deficiency and, therefore, provides a molecular explanation for the observed mutant phenotype.
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Affiliation(s)
- Michael Walter
- Institut für Botanik, Universität Münster, Schlossplatz 4, 48149 Münster, Germany
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Kahlau S, Bock R. Plastid transcriptomics and translatomics of tomato fruit development and chloroplast-to-chromoplast differentiation: chromoplast gene expression largely serves the production of a single protein. THE PLANT CELL 2008; 20:856-74. [PMID: 18441214 PMCID: PMC2390737 DOI: 10.1105/tpc.107.055202] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Plastid genes are expressed at high levels in photosynthetically active chloroplasts but are generally believed to be drastically downregulated in nongreen plastids. The genome-wide changes in the expression patterns of plastid genes during the development of nongreen plastid types as well as the contributions of transcriptional versus translational regulation are largely unknown. We report here a systematic transcriptomics and translatomics analysis of the tomato (Solanum lycopersicum) plastid genome during fruit development and chloroplast-to-chromoplast conversion. At the level of RNA accumulation, most but not all plastid genes are strongly downregulated in fruits compared with leaves. By contrast, chloroplast-to-chromoplast differentiation during fruit ripening is surprisingly not accompanied by large changes in plastid RNA accumulation. However, most plastid genes are translationally downregulated during chromoplast development. Both transcriptional and translational downregulation are more pronounced for photosynthesis-related genes than for genes involved in gene expression, indicating that some low-level plastid gene expression must be sustained in chromoplasts. High-level expression during chromoplast development identifies accD, the only plastid-encoded gene involved in fatty acid biosynthesis, as the target gene for which gene expression activity in chromoplasts is maintained. In addition, we have determined the developmental patterns of plastid RNA polymerase activities, intron splicing, and RNA editing and report specific developmental changes in the splicing and editing patterns of plastid transcripts.
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Affiliation(s)
- Sabine Kahlau
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany
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Zhou F, Karcher D, Bock R. Identification of a plastid intercistronic expression element (IEE) facilitating the expression of stable translatable monocistronic mRNAs from operons. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2007; 52:961-72. [PMID: 17825052 PMCID: PMC2230500 DOI: 10.1111/j.1365-313x.2007.03261.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2007] [Accepted: 07/12/2007] [Indexed: 05/17/2023]
Abstract
Most plastid genes are part of operons and expressed as polycistronic mRNAs. Many primary polycistronic transcripts undergo post-transcriptional processing in monocistronic or oligocistronic units. At least some polycistronic transcripts are not translatable, and endonucleolytic processing may therefore be a prerequisite for translation to occur. As the requirements for intercistronic mRNA processing into stable monocistronic transcript are not well understood, we have sought to define minimum sequence elements that trigger processing and thus are capable of generating stable translatable monocistronic mRNAs. We describe here the in vivo identification of a small intercistronic expression element that mediates intercistronic cleavage into stable monocistronic transcripts. Separation of foreign genes by this element facilitates transgene stacking in operons, and thus will help to expand the range of applications of transplastomic technology.
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Affiliation(s)
- Fei Zhou
- Max-Planck-Institut für Molekulare Pflanzenphysiologie (MPI-MP)Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Daniel Karcher
- Max-Planck-Institut für Molekulare Pflanzenphysiologie (MPI-MP)Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie (MPI-MP)Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
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Miyamoto T, Obokata J, Sugiura M. Recognition of RNA editing sites is directed by unique proteins in chloroplasts: biochemical identification of cis-acting elements and trans-acting factors involved in RNA editing in tobacco and pea chloroplasts. Mol Cell Biol 2002; 22:6726-34. [PMID: 12215530 PMCID: PMC134032 DOI: 10.1128/mcb.22.19.6726-6734.2002] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2002] [Revised: 05/13/2002] [Accepted: 06/20/2002] [Indexed: 11/20/2022] Open
Abstract
RNA editing in higher-plant chloroplasts involves C-to-U conversions at specific sites. Although in vivo analyses have been performed, little is known about the biochemical aspects of chloroplast editing reactions. Here we improved our original in vitro system and devised a procedure for preparing active chloroplast extracts not only from tobacco plants but also from pea plants. Using our tobacco in vitro system, cis-acting elements were defined for psbE and petB mRNAs. Distinct proteins were found to bind specifically to each cis-element, a 56-kDa protein to the psbE site and a 70-kDa species to the petB site. Pea chloroplasts lack the corresponding editing site in psbE since T is already present in the DNA. Parallel in vitro analyses with tobacco and pea extracts revealed that the pea plant has no editing activity for psbE mRNAs and lacks the 56-kDa protein, whereas petB mRNAs are edited and the 70-kDa protein is also present. Therefore, coevolution of an editing site and its cognate trans-factor was demonstrated biochemically in psbE mRNA editing between tobacco and pea plants.
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Sharma J, Panico M, Barber J, Morris HR. Characterization of the low molecular weight photosystem II reaction center subunits and their light-induced modifications by mass spectrometry. J Biol Chem 1997; 272:3935-43. [PMID: 9020097 DOI: 10.1074/jbc.272.7.3935] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
A sensitive and simple reverse phase HPLC purification scheme was developed for the rapid separation of the small protein subunits from photosystem II reaction center preparations. The precise molecular masses of the alpha- and beta-subunits of cytochrome b559 and the psbI gene product from pea plants, found to be 4394.6 +/- 0. 6, 9283.6 +/- 0.7, and 4209.5 +/- 0.5 Da, respectively, were then successfully determined for the first time by electrospray- and fast atom bombardment-mass spectrometry. Discrepancies between the molecular weights assigned and those calculated from the respective DNA sequences were observed for alpha- and beta-subunits of cytochrome b559. Currently, the nucleotide sequence of the psbI gene product from pea plants is not available. Application of novel mapping and sequencing strategies has assured the elucidation of full primary structures of all of the purified subunits. The modifications identified here include the post-translational processing of the initiating methionine on both subunits of cytochrome b559, NH2-terminal acetylation and an mRNA editing site at residue 26 (Ser --> Phe) on the beta-subunit, and retention of the NH2-terminal formyl-Met on the psbI gene product. In addition, specific oxidation of a single amino acid residue was identified on the psbI gene product and the beta-subunit purified from light-treated reaction center preparations. Overall, these studies provide the first detailed primary structural characterization of the small subunits of the reaction center complex and their associated light-induced modifications.
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Affiliation(s)
- J Sharma
- Wolfson Laboratories, Department of Biochemistry, Imperial College, London SW7 2AY, United Kingdom
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Mor TS, Ohad I, Hirschberg J, Pakrasi HB. An unusual organization of the genes encoding cytochrome b559 in Chlamydomonas reinhardtii: psbE and psbF genes are separately transcribed from different regions of the plastid chromosome. MOLECULAR & GENERAL GENETICS : MGG 1995; 246:600-4. [PMID: 7700232 DOI: 10.1007/bf00298966] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The psbE and psbF genes encode the apoproteins of cytochrome b559, an essential component of the pigment protein complex photosystem II. Together with psbL and psbJ, these genes constitute a single operon in all photosynthetic organisms examined thus far. We have cloned and sequenced the psbE and psbF genes of the Chlamydomonas reinhardtii plastid genome. The predicted amino-terminal domains of both polypeptides are more basic than those of other organisms, and the sequence of the psbE gene product indicates a departure from the 'positive-inside' rule for the insertion of proteins in the thylakoid membrane. Northern blot analysis demonstrated that psbE is transcribed into a 0.3 kb mRNA, while transcription of psbF and psbL genes results in a 0.9 kb transcript. The splitting of the psbEFLJ operon into separate transcription units suggests a unique mechanism of regulation of expression of these genes in C. reinhardtii.
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Affiliation(s)
- T S Mor
- Department of Biological Chemistry, Hebrew University of Jerusalem, Israel
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11
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Shuvalov VA, Fiege R, Schreiber U, Lendzian F, Lubitz W. EPR study of cytochrome in the D1D2 Cyt b-559 complex. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1995. [DOI: 10.1016/0005-2728(94)00168-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Alizadeh S, Nechushtai R, Barber J, Nixon P. Nucleotide sequence of the psbE, psbF and trnM genes from the chloroplast genome of Chlamydomonas reinhardtii. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1188:439-42. [PMID: 7803458 DOI: 10.1016/0005-2728(94)90067-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have determined the nucleotide sequences of the psbE and psbF genes, which encode the alpha and beta subunits, respectively, of cytochrome b-559, from the chloroplast genome of the green alga Chlamydomonas reinhardtii. In contrast to other organisms psbE is not co-transcribed with psbF. The primary structures of the gene products are very similar to the equivalent proteins in cyanobacteria and plants. Each subunit contains a single histidine residue that is thought to ligate haem. Upstream of the psbE gene, a trnM gene is located which encodes an elongator tRNA(Met) molecule.
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Affiliation(s)
- S Alizadeh
- Wolfson Laboratories, Department of Biochemistry, Imperial College of Science, Technology and Medicine, London, UK
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13
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Andersson B, Barber J. Composition, Organization, and Dynamics of Thylakoid Membranes. MOLECULAR PROCESSES OF PHOTOSYNTHESIS 1994. [DOI: 10.1016/s1569-2558(08)60394-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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14
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Cramer WA, Tae GS, Furbacher PN, Böttger M. The enigmatic cytochrome b-559 of oxygenic photosynthesis. PHYSIOLOGIA PLANTARUM 1993; 88:705-711. [PMID: 28741778 DOI: 10.1111/j.1399-3054.1993.tb01392.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The ubiquitous and obligatory association of cytochrome b-559 with the photosystem II reaction center of oxygenic photosynthesis is a conundrum since it seems not to have a function in the primary electron transport pathway of oxygen evolution. A model for the cytochrome structure that satisfies the cis-positive rule for membrane protein assembly consists of two short, non-identical hydrophobic membrane-spanning polypeptides (α and β), each containing a single histidine residue, as ligands for the bridging heme prosthetic group that is on the side of the membrane opposite to the water splitting apparatus. The ability of the heterodimer, but not the single α-subunit, to satisfy the cis-positive rule implies that the cytochrome inserts into the membrane as a heterodimer, with some evidence implicating it as the first membrane inserted unit of the assembling reaction center. The very positive redox potential of the cytochrome can be explained by a position for the heme in a hydrophobic niche near the stromal aqueous interface where it is also influenced by the large positive dipole potential of the parallel α-helices of the cytochrome. The requirement for the cytochrome in oxygenic photosynthesis may be a consequence of the presence of the strongly oxidizing reaction center needed for H2 O-splitting. This may lead to the need, under conditions of stress or plastid development, for an alternate source of electrons when the H2 O-splitting system is not operative as a source of reductant for the reaction center.
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Affiliation(s)
- William A Cramer
- Dept of Biological Sciences, Purdue Univ., West Lafayette, IN 47907 USA
| | - Gun-Sik Tae
- Dept of Biological Sciences, Purdue Univ., West Lafayette, IN 47907 USA
| | - Paul N Furbacher
- Dept of Biological Sciences, Purdue Univ., West Lafayette, IN 47907 USA
| | - Michel Böttger
- Dept of Biological Sciences, Purdue Univ., West Lafayette, IN 47907 USA
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Kawaguchi H, Fukuda I, Shiina T, Toyoshima Y. Dynamical behavior of psb gene transcripts in greening wheat seedlings. I. Time course of accumulation of the pshA through psbN gene transcripts during light-induced greening. PLANT MOLECULAR BIOLOGY 1992; 20:695-704. [PMID: 1450384 DOI: 10.1007/bf00046454] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The time course of the accumulation of the transcripts from 13 psb genes encoding a major part of the proteins composing photosystem II during light-induced greening of dark-grown wheat seedlings was examined focusing on early stages of plastid development (0.5 h through 72 h). The 13 genes can be divided into three groups. (1) The psbA gene is transcribed as a single transcript of 1.3 kb in the dark-grown seedlings, but its level increases 5- to 7-fold in response to light due to selective increase in RNA stability as well as in transcription activity. (2) The psbE-F-L-J operon, psbM and psbN genes are transcribed as a single transcript of 1.1 kb, two transcripts of 0.5 and 0.7 kb and a single transcript of 0.3 kb, respectively, in the dark-grown seedlings. The levels of accumulation of every transcript remain unchanged or rather decrease during plastid development under illumination. (3) The psbK-I-D-C gene cluster and psbB-H operon exhibit fairly complicated northern hybridization patterns during the greening process. When a psbC or psbD gene probe was used for northern hybridization, five transcripts differing in length were detected in the etioplasts from 5-day old dark-grown seedlings. After 2 h illumination, two new transcripts of different length appeared. Light induction of new transcripts was also observed in the psbB-H operon.
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Affiliation(s)
- H Kawaguchi
- Faculty of Integrated Arts & Sciences, Hiroshima University, Japan
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16
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Debus RJ. The manganese and calcium ions of photosynthetic oxygen evolution. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1102:269-352. [PMID: 1390827 DOI: 10.1016/0005-2728(92)90133-m] [Citation(s) in RCA: 970] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- R J Debus
- Department of Biochemistry, University of California Riverside 92521-0129
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17
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Comparison of Chloroplast and Mitochondrial Genome Evolution in Plants. PLANT GENE RESEARCH 1992. [DOI: 10.1007/978-3-7091-9138-5_3] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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18
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de Vitry C, Diner B, Popo J. Photosystem II particles from Chlamydomonas reinhardtii. Purification, molecular weight, small subunit composition, and protein phosphorylation. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)55345-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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19
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Willey DL, Gray JC. An open reading frame encoding a putative haem-binding polypeptide is cotranscribed with the pea chloroplast gene for apocytochrome f. PLANT MOLECULAR BIOLOGY 1990; 15:347-56. [PMID: 2103453 DOI: 10.1007/bf00036920] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The nucleotide sequence of a 1 kbp region of pea chloroplast DNA upstream from the gene petA encoding apocytochrome f has been determined. An open reading frame of 231 codons (ORF231) encoding a putative membrane-spanning polypeptide is separated by 205 bp from the coding region of petA. The open reading frame is homologous to open reading frames located in a similar position with respect to petA in chloroplast DNA from Marchantia polymorpha, tobacco, rice, wheat and Vicia faba. The sequence around a conserved histidine residue in a putative membrane-spanning region of the polypeptide resembles sequences present in cytochrome b from chromaffin granules and neutrophil membranes, suggesting that the open reading frame may encode a haem-binding polypeptide, possibly a b-type cytochrome. Northern hybridisation analysis indicates the presence in pea chloroplasts of a complex pattern of transcripts containing ORF231. Large transcripts of 5.5 kb, 4.3 kb, 3.4 kb and 2.7 kb encode both ORF231 and apocytochrome f, indicating that ORF231 and petA are co-transcribed.
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Affiliation(s)
- D L Willey
- Botany School, Cambridge Centre for Molecular Recognition, University of Cambridge, UK
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20
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Gingrich JC, Gasparich GE, Sauer K, Bryant DA. Nucleotide sequence and expression of the two genes encoding D2 protein and the single gene encoding the CP43 protein of Photosystem II in the cyanobacterium synechococcus sp. PCC 7002. PHOTOSYNTHESIS RESEARCH 1990; 24:137-150. [PMID: 24419907 DOI: 10.1007/bf00032594] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/1989] [Accepted: 10/26/1989] [Indexed: 06/03/2023]
Abstract
The unicellular photoheterotrophic cyanobacterium Synechococcus sp. PCC 7002 was shown to encode two genes for the Photosystem II reaction center core protein D2 and one gene for the reaction center chlorophyhll-binding protein CP43. These three genes were cloned and their DNA sequences determined along with their flanking DNA sequences. Northern hybridization experiments show that both genes which encode D2, psbD1 and psbD2, are expressed at roughly equivalent levels. For each of the two psbD genes, there are 18 nucleotide differences among the 1059 nucleotides which are translated. The DNA sequences surrounding the coding sequences are nearly 70% divergent. Despite the DNA sequence differences in the genes, the proteins encoded by the two genes are predicted to be identical. The proteins encoded by psbD1 and psbD2 are ∼92% homologous to other sequenced cyanobacterial psbD genes and ∼86% homologous to sequenced chloroplast-encoded psbD genes.The single gene for CP43, psbC, overlaps the 3' end of psbD1 and is co-transcribed with it. Results from previous sequencing of psbC genes encoded by chloroplasts suggest that the 5' end of the psbC gene overlaps the 3' end of the coding sequence of psbD by ∼50 nucleotides. In Synechococcus sp. PCC 7002, the methionine codon previously proposed to be the start codon for psbC is replaced by an ACG (threonine) codon. We propose an alternative start for the psbC gene at a GTG codon 36 nucleotides downstream from the threonine codon. This GTG codon is preceded by a consensus E. coli-like ribosome binding sequence. Both the GTG start codon and its preceding ribosome binding sequence are conserved in all psbC genes sequenced from cyanobacteria and chloroplasts. This suggests that all psbC genes start at this alternative GTG codon. Based on this alternative start codon, the gene product is ∼85% identical to other cyanobacterial psbC gene products and ∼77% identical to eucaryotic chloroplast-encoded psbC gene products.
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Affiliation(s)
- J C Gingrich
- Chemical Biodynamics Division, Lawrence Berkeley Laboratory, University of California, 94720, Berkeley, CA, USA
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