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Current Opinion in Microbiology Aug 1999The discovery of a plastid in Plasmodium, Toxoplasma and related protozoan parasites provides a satisfying resolution to several long-standing mysteries: the mechanism... (Review)
Review
The discovery of a plastid in Plasmodium, Toxoplasma and related protozoan parasites provides a satisfying resolution to several long-standing mysteries: the mechanism of action for various surprisingly effective antibiotics; the subcellular location of an enigmatic 35 kb episomal DNA; and the nature of an unusual intracellular structure containing multiple membranes. The apicomplexan plastid highlights the importance of lateral genetic transfer in evolution and provides an accessible system for the investigation of protein targeting to secondary endosymbiotic organelles. Combining molecular genetic identification of targeting signals with whole genome analysis promises to yield a complete picture of organellar metabolic pathways and new targets for drug design.
Topics: Animals; Apicomplexa; Biological Evolution; Biological Transport; Plastids; Protozoan Proteins
PubMed: 10458993
DOI: 10.1016/S1369-5274(99)80075-7 -
Biochimica Et Biophysica Acta Sep 2015The development of a repressible chloroplast gene expression system in Chlamydomonas reinhardtii has opened the door for studying the role of essential chloroplast... (Review)
Review
The development of a repressible chloroplast gene expression system in Chlamydomonas reinhardtii has opened the door for studying the role of essential chloroplast genes. This approach has been used to analyze three chloroplast genes of this sort coding for the α subunit of RNA polymerase (rpoA), a ribosomal protein (rps12) and the catalytic subunit of the ATP-dependent ClpP protease (clpP1). Depletion of the three corresponding proteins leads to growth arrest and cell death. Shutdown of chloroplast transcription and translation increases the abundance of a set of plastid transcripts that includes mainly those involved in transcription, translation and proteolysis and reveals multiple regulatory feedback loops in the chloroplast gene circuitry. Depletion of ClpP profoundly affects plastid protein homeostasis and elicits an autophagy-like response with extensive cytoplasmic vacuolization of cells. It also triggers changes in chloroplast and nuclear gene expression resulting in increased abundance of chaperones, proteases, ubiquitin-related proteins and proteins involved in lipid trafficking and thylakoid biogenesis. These features are hallmarks of an unfolded protein response in the chloroplast and raise new questions on plastid protein homeostasis and plastid signaling. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
Topics: Autophagy; Chloroplast Proteins; Gene Expression Regulation, Plant; Genes, Chloroplast; Lipid Metabolism; Plastids; Quality Control; Signal Transduction
PubMed: 25486627
DOI: 10.1016/j.bbabio.2014.11.011 -
Plant Cell Reports Apr 2022Global survey of plastid gene expression during fruit ripening in kiwifruit provides cis-elements for the future engineering of the plastid genome of kiwifruit. A...
Global survey of plastid gene expression during fruit ripening in kiwifruit provides cis-elements for the future engineering of the plastid genome of kiwifruit. A limitation in the application of plastid biotechnology for molecular farming is the low-level expression of transgenes in non-green plastids compared with photosynthetically active chloroplasts. Unlike other fruits, not all chloroplasts are transformed into chromoplasts during ripening of red-fleshed kiwifruit (Actinidia chinensis cv. Hongyang) fruits, which may make kiwifruit an ideal horticultural plant for recombinant protein production by plastid engineering. To identify cis-elements potentially triggering high-level transgene expression in edible tissues of the 'Hongyang' kiwifruit, here we report a comprehensive analysis of kiwifruit plastid gene transcription in green leaves and fruits at three different developmental stages. While transcripts of a few photosynthesis-related genes and most genetic system genes were substantially upregulated in green fruits compared with leaves, nearly all plastid genes were significantly downregulated at the RNA level during fruit development. Expression of a few genes remained unchanged, including psbA, the gene encoding the D1 polypeptide of photosystem II. However, PsbA protein accumulation decreased continuously during chloroplast-to-chromoplast differentiation. Analysis of post-transcriptional steps in mRNA maturation, including intron splicing and RNA editing, revealed that splicing and editing may contribute to regulation of plastid gene expression. Altogether, 40 RNA editing sites were verified, and 5 of them were newly discovered. Taken together, this study has generated a valuable resource for the analysis of plastid gene expression and provides cis-elements for future efforts to engineer the plastid genome of kiwifruit.
Topics: Actinidia; Fruit; Gene Expression Regulation, Plant; Plant Proteins; Plastids; Transcription, Genetic
PubMed: 35226116
DOI: 10.1007/s00299-022-02840-7 -
The Plant Cell Sep 2023
Topics: Plastids; Genome, Mitochondrial; Transformation, Genetic
PubMed: 37352126
DOI: 10.1093/plcell/koad179 -
Journal of Experimental Botany Mar 2005Stromules (stroma-filled tubules) are highly dynamic structures extending from the surface of all plastid types examined so far, including proplastids, chloroplasts,... (Review)
Review
Stromules (stroma-filled tubules) are highly dynamic structures extending from the surface of all plastid types examined so far, including proplastids, chloroplasts, etioplasts, leucoplasts, amyloplasts, and chromoplasts. Stromules are usually 0.35-0.85 microm in diameter and of variable length, from short beak-like projections to linear or branched structures up to 220 mum long. They are enclosed by the inner and outer plastid envelope membranes and enable the transfer of molecules as large as Rubisco (approximately 560 kDa) between interconnected plastids. Stromules occur in all cell types, but stromule morphology and the proportion of plastids with stromules vary from tissue to tissue and at different stages of plant development. In general, stromules are more abundant in tissues containing non-green plastids, and in cells containing smaller plastids. The primary function of stromules is still unresolved, although the presence of stromules markedly increases the plastid surface area, potentially increasing transport to and from the cytosol. Other functions of stromules, such as transfer of macromolecules between plastids and starch granule formation in cereal endosperm, may be restricted to particular tissues and cell types.
Topics: Gene Expression; Green Fluorescent Proteins; Plant Cells; Plant Development; Plant Leaves; Plant Roots; Plant Stems; Plants; Plastids; Seeds; Signal Transduction
PubMed: 15699062
DOI: 10.1093/jxb/eri088 -
International Review of Cytology 2003Apicomplexan parasites cause severe diseases such as malaria, toxoplasmosis, and coccidiosis (caused by Plasmodium spp., Toxoplasma, and Eimeria, respectively). These... (Review)
Review
Apicomplexan parasites cause severe diseases such as malaria, toxoplasmosis, and coccidiosis (caused by Plasmodium spp., Toxoplasma, and Eimeria, respectively). These parasites contain a relict plastid-termed "apicoplast"--that originated from the engulfment of an organism of the red algal lineage. The apicoplast is indispensable but its exact role in parasites is unknown. The apicoplast has its own genome and expresses a small number of genes, but the vast majority of the apicoplast proteome is encoded in the nuclear genome. The products of these nuclear genes are posttranslationally targeted to the organelle via the secretory pathway courtesy of a bipartite N-terminal leader sequence. Apicoplasts are nonphotosynthetic but retain other typical plastid functions such as fatty acid, isoprenoid and heme synthesis, and products of these pathways might be exported from the apicoplast for use by the parasite. Apicoplast pathways are essentially prokaryotic and therefore excellent drug targets. Some antibiotics inhibiting these molecular processes are already in chemotherapeutic use, whereas many new drugs will hopefully spring from our growing understanding of this intriguing organelle.
Topics: Animals; Apicomplexa; Cell Nucleus; Energy Metabolism; Genome; Plasmodium falciparum; Plastids; Protein Transport; Protozoan Infections; Rhodophyta
PubMed: 12722949
DOI: 10.1016/s0074-7696(05)24003-2 -
Journal of Plant Research Mar 2010It is widely believed that plastid and mitochondrial genomes are inherited through the maternal parent. In plants, however, paternal transmission of these genomes is... (Review)
Review
It is widely believed that plastid and mitochondrial genomes are inherited through the maternal parent. In plants, however, paternal transmission of these genomes is frequently observed, especially for the plastid genome. A male gametic trait, called potential biparental plastid inheritance (PBPI), occurs in up to 20% of angiosperm genera, implying a strong tendency for plastid transmission from the male lineage. Why do plants receive organelles from the male parents? Are there clues in plastids that will help to elucidate the evolution of plants? Reconstruction of the ancestral state of plastid inheritance patterns in a phylogenetic context provides insights into these questions. In particular, a recent report demonstrated the unilateral occurrence of PBPI in angiosperms. This result implies that nuclear cytoplasmic conflicts, a basic driving force for altering the mode of organelle inheritance, might have arisen specifically in angiosperms. Based on existing evidence, it is likely that biparental inheritance may have occurred to rescue angiosperm species with defective plastids.
Topics: Biological Evolution; Extrachromosomal Inheritance; Genome, Plastid; Magnoliopsida; Plastids
PubMed: 20052516
DOI: 10.1007/s10265-009-0291-z -
Plant Biotechnology Journal Jun 2011The ability to manipulate plant fatty acid biosynthesis by using new biotechnological approaches has allowed the production of transgenic plants with unusual fatty acid... (Review)
Review
The ability to manipulate plant fatty acid biosynthesis by using new biotechnological approaches has allowed the production of transgenic plants with unusual fatty acid profile and increased oil content. This review focuses on the production of very long chain polyunsaturated fatty acids (VLCPUFAs) and the increase in oil content in plants using molecular biology tools. Evidences suggest that regular consumption of food rich in VLCPUFAs has multiple positive health benefits. Alternative sources of these nutritional fatty acids are found in cold-water fishes. However, fish stocks are in severe decline because of decades of overfishing, and also fish oils can be contaminated by the accumulation of toxic compounds. Recently, there is also an increase in oilseed use for the production of biofuels. This tendency is partly associated with the rapidly rising costs of petroleum, increased concern about the environmental impact of fossil oil and the attractive need to develop renewable sources of fuel. In contrast to this scenario, oil derived from crop plants is normally contaminant free and less environmentally aggressive. Genetic engineering of the plastid genome (plastome) offers a number of attractive advantages, including high-level foreign protein expression, marker-gene excision and transgene containment because of maternal inheritance of plastid genome in most crops. Here, we describe the possibility to improve fatty acid biosynthesis in plastids, production of new fatty acids and increase their content in plants by genetic engineering of plastid fatty acid biosynthesis via plastid transformation.
Topics: Biofuels; Fatty Acids, Unsaturated; Fish Oils; Food; Genetic Engineering; Plants, Genetically Modified; Plastids
PubMed: 21535359
DOI: 10.1111/j.1467-7652.2011.00621.x -
The Plant Cell Feb 2019
Topics: Abscisic Acid; Arabidopsis Proteins; Chloroplasts; Plastids
PubMed: 30705132
DOI: 10.1105/tpc.19.00049 -
Current Issues in Molecular Biology Jan 2005The apicoplast is a plastid organelle, homologous to chloroplasts of plants, that is found in apicomplexan parasites such as the causative agents of Malaria Plasmodium... (Review)
Review
The apicoplast is a plastid organelle, homologous to chloroplasts of plants, that is found in apicomplexan parasites such as the causative agents of Malaria Plasmodium spp. It occurs throughout the Apicomplexa and is an ancient feature of this group acquired by the process of endosymbiosis. Like plant chloroplasts, apicoplasts are semi-autonomous with their own genome and expression machinery. In addition, apicoplasts import numerous proteins encoded by nuclear genes. These nuclear genes largely derive from the endosymbiont through a process of intracellular gene relocation. The exact role of a plastid in parasites is uncertain but early clues indicate synthesis of lipids, heme and isoprenoids as possibilities. The various metabolic processes of the apicoplast are potentially excellent targets for drug therapy.
Topics: Animals; Antiprotozoal Agents; Apicomplexa; Phylogeny; Plastids; Protein Transport
PubMed: 15580780
DOI: No ID Found