Assembly of Photosystem II

Erickson, Jeanne M.

doi:10.1007/0-306-48204-5_15

Cited by 5 publications

(4 citation statements)

References 216 publications

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“…The psb genes studied in the present work. The function and location of the respective gene products, as well as their importance for photoautotrophic growth in cyanobacteria (E, essential or N, non-essential) are also shown (for reviews, see Ikeuchi 1992 andErickson 1998 tion in the dark. Loss of the psbA transcripts was less dramatic; 80% of these transcripts remained after 1 h of dark treatment, but after a prolonged dark incubation (up to 12 h; see also Fig.…”

Section: Resultsmentioning

confidence: 99%

“…In addition to the D1/D2 heterodimer, PSII reaction centre preparations contain the h and i subunits of cytochrome b 559 (psbE and psbF gene products, respectively) and the psbI gene product (Nanba andSatoh 1987, Ikeuchi andInoue 1988). Closely associated with this reaction centre are the light-harvesting inner antenna proteins CP47 (psbB gene product) and CP43 (psbC gene product) as well as several small proteins, whose functions are still largely unknown (reviewed by Ikeuchi 1992 andErickson 1998). On the lumenal side, the PSII core complex is associated with the extrinsic proteins of the oxygen-evolving complex, collectively forming the oxygen-evolving PSII core complex (Kuwabara et al 1985, Shen et al 1992).…”

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confidence: 99%

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Two distinct mechanisms regulate the transcription of photosystem II genes in Synechocystis sp. PCC 6803

Herranen¹,

Aro²,

Tyystjärvi³

2001

Physiologia Plantarum

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Expression and regulation of psb genes, encoding various subunits of photosystem II (PSII), were studied in the cyanobacterium Synechocystis sp. PCC 6803. Transcription of the psbA and psbD genes, encoding the PSII reaction centre proteins D1 and D2, was rapidly activated upon onset of illumination and the transcription rates were enhanced at high irradiance. Gel retardation analysis demonstrated dark-enhanced binding of proteins to the upstream region of the psbA2 gene, pointing to a repressor-protein-based transcriptional regulation mechanism. Transcription of all the other psb genes also required light, but unlike the psbA and psbD genes, these psb genes did not respond specifically to high-light. Moreover, the transcription of these psb genes was activated slowly at onset of illumination, and was strictly dependent on de novo protein synthesis. We suggest that these psb genes are up-regulated in the light via transcriptional activator proteins, and the slow activation may be related to production of new PSII centres during growth. Apart from the two distinct mechanisms for transcriptional regulation, all psb genes shared a common regulation mechanism at the level of transcript stability, mediated by the redox poise of intersystem electron carrier(s).

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Two distinct mechanisms regulate the transcription of photosystem II genes in Synechocystis sp. PCC 6803

Herranen¹,

Aro²,

Tyystjärvi³

2001

Physiologia Plantarum

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“…synthesized one and has been localized to the stroma lamellae of thylakoid membranes. Subsequently, intact PS II is moving to its functional localization in the grana regions [44]. Assuming a cotranslational insertion of D1 [45], it appears likely that gene expression for this repair mechanism is restricted to the subfraction of the stromal thylakoid membranes, especially, as the tightly stacked grana regions would not allow access of the RNA polymerase, ribosomes or other soluble complexes involved in chloroplast gene expression to the membrane.…”

Section: Discussionmentioning

confidence: 99%

“…It combines properties, which have to be postulated for such a factor, namely, it is associated with stromal thylakoids and binds to RNA. In particular, the fact that RBP63 binds with high affinity to the psbA 5¢ UTR and might thereby target the mRNA at stromal thylakoid membranes is striking, as most translational activity in mature chloroplasts is restricted to D1 synthesis due to constraints of PS II repair [44].…”

Section: Discussionmentioning

confidence: 99%

A chloroplast RNA binding protein from stromal thylakoid membranes specifically binds to the 5′ untranslated region of the psbA mRNA

Ossenbühl

Hartmann

Nickelsen

2002

European Journal of Biochemistry

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The intrachloroplastic localization of post-transcriptional gene expression steps represents one key determinant for the regulation of chloroplast development. We have characterized an RNA binding protein of 63 kDa (RBP63) from Chlamydomonas reinhardtii chloroplasts, which cofractionates with stromal thylakoid membranes. Solubility properties suggest that RBP63 is a peripheral membrane protein. Among RNA probes from different 5¢ untranslated regions of chloroplast transcripts, RBP63 preferentially binds to the psbA leader. This binding is dependent on a region comprising seven consecutive A residues, which is required for D1 protein synthesis. A possible role for this newly discovered RNA binding protein in membrane targeting of psbA gene expression is discussed.Keywords: chloroplast gene expression; D1 synthesis; membrane targeting; RNA binding; thylakoid.Chloroplast gene expression within plant or algal cells has been shown to be dependent upon nuclear gene products, which are translated in the cytoplasm and, subsequently, are imported by the organelle. Herein, they fulfil their function by interacting with distinct elements and/or factors associated with the chloroplast gene expression machinery [1,2]. While the molecular mechanisms of regulatory interaction during these processes are being pieced together, relatively little is known about the intrachloroplast localization of different steps of gene expression.For instance, the chloroplast DNA is organized in nucleoids. In developing higher plants, these are associated with the inner plastid envelope through the PEND protein.Upon full chloroplast maturation, the cpDNA is localized to thylakoid membranes by an undetermined mechanism [3]. This suggests that the plastid transcription machinery is distributed in a similar way. Further evidence for subcompartmentalization of chloroplast gene expression has been obtained by the recent cloning of genetically defined loci, which are required for distinct post-transcriptional steps of chloroplast gene expression. These factors could be detected in the stromal compartment like Crp1 and Crs2 in maize [4,5], or Maa3, Mbb1 and Nac2 in Chlamydomonas reinhardtii [6,7,8], which are involved in processing/splicing or stabilization of specific chloroplast transcripts, respectively. Conversely, association with the inner plastid envelope and/or the so-called low density membranes (LDM), which resemble the inner envelope membrane with regard to their lipid composition [9], has been observed for the translation termination factor RF4 from spinach and the RNA splicing factor Maa2 from C. reinhardtii [10,11].By application of in vitro run-on translation systems, a cotranslational insertion of thylakoid membrane proteins has been reported [12]. This is consistent with the finding that chloroplast psbA and psbD transcripts are associated with thylakoids [13,14]. Further evidence for an essential role of the thylakoid membrane for chloroplast gene expression was deduced from the analysis of a maize mutant lacking the chloroplast SecY ...

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Synthesis, assembly and degradation of thylakoid membrane proteins

2000

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The thylakoid membrane of chloroplasts contains four major protein complexes, involved in the photosynthetic electron transfer chain and in ATP synthesis. These complexes are built from a large number of polypeptide subunits encoded either in the nuclear or in the plastid genome. In this review, we are considering the mechanism that couples assembly (association of the polypeptides with each other and with their cofactors) with the upstream and downstream steps of the biogenetic pathway, translation and proteolytic degradation. We present the contrasting images of assembly that have emerged from a variety of approaches (studies of photosynthesis mutants, developmental studies and direct biochemical analysis of the kinetics of assembly). We develop the concept of control by epistasy of synthesis, through which the translation of certain subunits is controlled by the state of assembly of the complex and address the question of its mechanisms. We describe additional factors that assist in the integration and assembly of thylakoid membrane proteins.

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Assembly of Photosystem II

Cited by 5 publications

References 216 publications

Two distinct mechanisms regulate the transcription of photosystem II genes in Synechocystis sp. PCC 6803

Two distinct mechanisms regulate the transcription of photosystem II genes in Synechocystis sp. PCC 6803

A chloroplast RNA binding protein from stromal thylakoid membranes specifically binds to the 5′ untranslated region of the psbA mRNA

Synthesis, assembly and degradation of thylakoid membrane proteins

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