Chloroplast ribosomal proteins and their genes

Mache, Régis

doi:10.1016/0168-9452(90)90180-v

Cited by 43 publications

(24 citation statements)

References 77 publications

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“…Chloroplast 70S ribosomes contain about 60 different protein components (14,34,67,103), several more protein species than those in E. coli ribosomes (21 proteins in the 30S subunit and 34 proteins in the 50S subunit). In land plant chloroplasts, one third of the ribosomal proteins are encoded by ctDNA and the remaining two thirds are encoded in the nuclear genome.…”

Section: Ribosomal Protein Gene Clustersmentioning

confidence: 99%

Evolution and Mechanism of Translation in Chloroplasts

1998

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The entire sequence (120-190 kb) of chloroplast genomes has been determined from a dozen plant species. The genome contains from 87 to 183 known genes, of which half encode components involved in translation. These include a complete set of rRNAs and about 30 tRNAs, which are likely to be sufficient to support translation in chloroplasts. RNA editing (mostly C to U base changes) occurs in some chloroplast transcripts, creating start and stop codons and changing codons to retain conserved amino acids. Many components that constitute the chloroplast translational machinery are similar to those of Escherichia coli, whereas only one third of the chloroplast mRNAs contain Shine-Dalgarno-like sequences at the correct positions. Analyses conducted in vivo and in vitro have revealed the existence of multiple mechanisms for translational initiation in chloroplasts.

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Section: Ribosomal Protein Gene Clustersmentioning

confidence: 99%

Evolution and Mechanism of Translation in Chloroplasts

1998

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“…3) soundly reflects the evolution of the species and organelles under study, explanations must be sought in the evolution of 16S rRNA genes which may account for the data. Aside from the problems of fluctuating GC content in bacterial evolution (Muto and Osawa 1987), one may recall that ribosomal RNAs evolve in the structural context of roughly 60 ribosomal proteins, about two-thirds of which are encoded by the nucleus in higher plants and green algae (Christopher et al 1988;Mache 1990;Subramanian et al 1991). Moreover, plastid ribosomes possess a number of unique features which their counterparts in free-living prokaryotes do not (Zhou and Mache 1989;Subramanian et al 1991).…”

Section: Origins Of Plastidsmentioning

confidence: 99%

Molecular phylogenies of plastid origins and algal evolution

1992

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An overview of recent molecular analyses regarding origins of plastids in algal lineages is presented. Since different phylogenetic analyses can yield contradictory views of algal plastid origins, we have examined the effect of two distance measurement methods and two distance matrix tree-building methods upon topologies for the ribulose-l,5-bisphosphate carboxylase/oxygenase large subunit nucleotide sequence data set. These results are contrasted to those from bootstrap parsimony analysis of nucleotide sequence data subsets. It is shown that the phylogenetic information contained within nucleotide sequences for the chloroplastencoded gene for the large subunit of ribulose-l,5-bisphosphate carboxylase/oxygenase, integral to photosynthesis, indicates an independent origin for this plastid gene in different plant taxa. This finding is contrasted to contrary results derived from 16S rRNA sequences. Possible explanations for discrepancies observed for these two different molecules are put forth. Other molecular sequence data which address questions of early plant evolution and the eubacterial origins of algal organelles are discussed.

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“…After being centrifuged at 3,000 x g for 10 min, nuclei were lysed with buffer III (110 mM KCI, After being incubated at 4°C for 30 min, the proteins were collected by centrifugation at 10,000 x g for 15 min. The pellets were resuspended in a minimal volume of buffer IV (40 mM KCI, 25 Fig. 8), was labelled with Klenow enzyme at the BamHI site.…”

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confidence: 99%

Structure and expression of the nuclear gene coding for the chloroplast ribosomal protein L21: developmental regulation of a housekeeping gene by alternative promoters.

Lagrange¹,

Franzetti²,

Axelos³

et al. 1993

Mol. Cell. Biol.

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We have cloned and sequenced the nuclear gene of the chloroplast ribosomal protein L21 (rpI2l) of Spinacia oleracea. The gene consists of five exons and four introns. All introns are located in the sequence which corresponds to the Escherichia coli-like central core of the protein. L21 mRNA is present in photosynthetic (leaves) and nonphotosynthetic (roots and seeds) plant organs, although large quantitative differences exist. Primer extension and Si nuclease mapping experiments revealed the existence of two types of transcripts in leaves. The two corresponding start sites were defined as P1 and P2. In roots and seeds, we found only the shorter of the two transcripts (initiated at P2). The nucleotide sequence surrounding P2 resembles promoters for housekeeping and vertebrate r-protein genes. Analysis of several promoter constructions by transient expression confirmed that both transcripts originate from transcription initiation. Results are interpreted to mean that the expression of the rpI21 gene is regulated by alternative promoters. One of the promoters (P2) is constitutive, and the other one (P1) is specifically induced in leaves, i.e., its activation should be related to the transformation of amyloplasts or proplastids to chloroplasts. The gene thus represents the first example of a housekeeping gene which is regulated by the organ-specific usage of alternative promoters. Primer extension analysis and S1 nuclease mapping of another nucleus-encoded chloroplast ribosomal protein gene (rpsl) give evidence that the same type of regulation by two-promoter usage might be a more general phenomenon of plant chloroplast-related ribosomal protein genes. Preliminary results indicate the presence of conserved sequences within the rpl2l and rpsl promoter regions which compete for the same DNA binding activities.Plastids are essential components of plant cells. Depending on their function within a defined plant tissue or organ, plastids differentiate into several types of organelles. They are present as chloroplasts in photosynthetically active cells of leaves, as amyloplasts and proplastids in root cells and seeds, and as chromoplasts in fruit and flower cells.The transformation of plastids into these specialized types of organelles is necessarily based on changes in gene expression within the organelles as well as changes in the expression of nuclear-encoded plastid proteins. These changes concern the induction and/or repression of the expression of plastid-specific genes, but they also have to include modulated expression of genes which are necessary for the genetic functions of all types of organelles. In this respect, we are especially interested in how different types of plastids maintain their translational capacities, e.g., in the regulation of ribosomal gene expression during plastid differentiation.The present knowledge on ribosomal gene expression originates mainly from studies of procaryotic and animal systems. It has been shown previously that the rate of ribosome formation is adapted to the individual cell...

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Chloroplast ribosomal proteins and their genes

Cited by 43 publications

References 77 publications

Evolution and Mechanism of Translation in Chloroplasts

Evolution and Mechanism of Translation in Chloroplasts

Molecular phylogenies of plastid origins and algal evolution

Structure and expression of the nuclear gene coding for the chloroplast ribosomal protein L21: developmental regulation of a housekeeping gene by alternative promoters.

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