共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
Dual targeting of organellar seryl-tRNA synthetase to maize mitochondria and chloroplasts 总被引:2,自引:0,他引:2
Aminoacyl-tRNA synthetases (AARSs) play a critical role in translation and are thus required in three plant protein-synthesizing compartments: cytosol, mitochondria and plastids. A systematic study had previously shown extensive sharing of organellar AARSs from Arabidopsis thaliana, mostly between mitochondria and chloroplasts. However, distribution of AARSs from monocot species, such as maize, has never been experimentally investigated. Here we demonstrate dual targeting of maize seryl-tRNA synthetase, SerZMo, into both mitochondria and chloroplasts using combination of complementary methods, including in vitro import assay, transient expression analysis of green fluorescent protein (GFP) fusions and immunodetection. We also show that SerZMo dual localization is established by the virtue of an ambiguous targeting peptide. Full-length SerZMo protein fused to GFP is targeted to chloroplast stromules, indicating that SerZMo protein performs its function in plastid stroma. The deletion mutant lacking N-terminal region of the ambiguous SerZMo targeting peptide was neither targeted into mitochondria nor chloroplasts, indicating the importance of this region in both mitochondrial and chloroplastic import. 相似文献
3.
It was previously shown that AtNAP1 is a plastidic SufB protein involved in Fe-S cluster assembly in Arabidopsis. In this study, we investigated the effects of depleting SufB protein from plant cells using virus-induced gene silencing (VIGS). VIGS of NbNAP1 encoding a Nicotiana benthamiana homolog of AtNAP1 resulted in a leaf yellowing phenotype. NbNAP1 was expressed ubiquitously in plant tissues with the highest level in roots. A GFP fusion protein of the N-terminal region (M1-V103) of NbNAP1 was targeted to chloroplasts. Depletion of NbNAP1 resulted in reduced numbers of chloroplasts of reduced size. Mitochondria also seemed to be affected. Despite the reduced number and size of the chloroplasts in the NbNAP1 VIGS lines, the expression of many nuclear genes encoding chloroplast-targeted proteins and chlorophyll biosynthesis genes remained unchanged. 相似文献
4.
5.
PRBP plays a role in plastid ribosomal RNA maturation and chloroplast biogenesis in <Emphasis Type="Italic">Nicotiana benthamiana</Emphasis> 总被引:1,自引:0,他引:1
In the present study, we investigated protein characteristics and physiological functions of PRBP (plastid RNA-binding protein)
in Nicotiana benthamiana. PRBP fused to green fluorescent protein (GFP) localized to the chloroplasts. Recombinant PRBP proteins bind to single-stranded
RNA in vitro, but not to DNA in a double- or a single-stranded form. Virus-induced gene silencing (VIGS) of PRBP resulted in leaf yellowing in N. benthamiana. At the cellular level, PRBP depletion disrupted chloroplast biogenesis: chloroplast number and size were reduced, and the
thylakoid membrane was poorly developed. In PRBP-silenced leaves, protein levels of plastid-encoded genes were significantly reduced, whereas their mRNA levels were normal
regardless of their promoter types indicating that PRBP deficiency primarily affects translational or post-translational processes.
Depletion of PRBP impaired processing of the plastid-encoded 4.5S ribosomal RNA, resulting in accumulation of the larger precursor
rRNAs in the chloroplasts. In addition, PRBP-deficient chloroplasts contained significantly reduced levels of mature 4.5S
and 5S rRNAs in the polysomal fractions, indicating decreased chloroplast translation. These results suggest that PRBP plays
a role in chloroplast rRNA processing and chloroplast development in higher plants. 相似文献
6.
Yong-Won Kang Jae-Yong Lee Young Jeon Gang-Won Cheong Moonil Kim Hyun-Sook Pai 《Plant molecular biology》2010,72(6):569-583
Sulfite reductase (SiR) performs dual functions, acting as a sulfur assimilation enzyme and as a chloroplast (cp-) nucleoid
binding protein. In this study, we examined the in vivo effects of SiR deficiency on chloroplast development in Nicotiana benthamiana. Virus-induced gene silencing of NbSiR resulted in leaf yellowing and growth retardation phenotypes, which were not rescued by cysteine supplementation. NbSiR:GFP
fusion protein was targeted to chloroplasts and colocalized with cp-nucleoids. Recombinant full-length NbSiR protein and the
C-terminal half of NbSiR possessed cp-DNA compaction activities in vitro, and expression of full-length NbSiR in E. coli caused condensation of genomic DNA. NbSiR silencing differentially affected expression of plastid-encoded genes, inhibiting expression of several genes more severely
than others. In the later stages, depletion of NbSiR resulted in chloroplast ablation. In NbSiR-silenced plants, enlarged cp-nucleoids containing an increased amount of cp-DNA were observed in the middle of the abnormal
chloroplasts, and the cp-DNAs were predominantly of subgenomic sizes based on pulse field gel electrophoresis. The abnormal
chloroplasts developed prolamellar body-like cubic lipid structures in the light without accumulating NADPH:protochlorophyllide
oxidoreductase proteins. Our results suggest that NbSiR plays a role in cp-nucleoid metabolism, plastid gene expression, and
thylakoid membrane development. 相似文献
7.
Isoprenoid biosynthesis in plants occurs by two independent pathways: the cytosolic mevalonate (MVA) pathway and the plastidic
methylerythritol phosphate (MEP) pathway. In this study, we investigated the cellular effects of depletion of IspE, a protein
involved in the MEP pathway, using virus-induced gene silencing (VIGS). The IspE gene is preferentially expressed in young tissues, and induced by light and methyl jasmonate. The GFP fusion protein of IspE
was targeted to chloroplasts. Reduction of IspE expression by VIGS resulted in a severe leaf yellowing phenotype. At the cellular level, depletion of IspE severely affected
chloroplast development, dramatically reducing both the number and size of chloroplasts. Interestingly, mitochondrial development
was also impaired, suggesting a possibility that the plastidic MEP pathway contributes to mitochondrial isoprenoid biosynthesis
in leaves. A deficiency in IspE activity decreased cellular levels of the metabolites produced by the MEP pathway, such as
chlorophylls and carotenoids, and stimulated expression of some of the downstream MEP pathway genes, particularly IspF and IspG. Interestingly, the IspE VIGS lines had significantly increased numbers of cells of reduced size in all leaf layers, compared
with TRV control and other VIGS lines for the MEP pathway genes. The increased cell division in the IspE VIGS lines was particularly
pronounced in the abaxial epidermal layer, in which the over-proliferated cells bulged out of the plane, making the surface
uneven. In addition, trichome numbers dramatically increased and the stomata size varied in the affected tissues. Our results
show that IspE deficiency causes novel developmental phenotypes distinct from the phenotypes of other MEP pathway mutants,
indicating that IspE may have an additional role in plant development besides its role in isoprenoid biosynthesis.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Genbank accession number for IspE: ABO87658. 相似文献
8.
9.
10.
11.
12.
Summary It has been suggested that cyanobacteria served as the ancestors for rhodophytic algae whose chloroplasts contain chlorophyll a and phycobilins, and that a rhodophyte served as the plastid source for chromophytic plants that contain chlorophylls a and c. Although organellar DNA has been used to assess phylogenetic relatedness among terrestrial plants and green algae whose chloroplasts contain chlorophylls a and b, few data are presently available on the molecular profile of plastid DNA in chromophytes or rhodophytes.In this study the chloroplast genome of the rhodophytic, filamentous alga Griffithsia pacifica has been characterized. DNA was purified from isolated chloroplasts using protease k treatment and sodium dodecyl sulfate lysis followed by density centrifugation in Hoescht-33258 dye-CsCl gradients. Single and double restriction enzyme digests demonstrate that the DNA prepared from purified chloroplasts has a genome size of about 178 kilobase pairs (kb). A restriction map of this chloroplast genome demonstrates that it is circular and, unlike the chloroplast DNA (cpDNA) in most other plants, contains only a single ribosomal DNA operon. DNA was also purified from the mitochondria that co-isolated with chloroplasts. Mitochondrial DNA consists of molecules that range in size from 27 to 350 kb based on restriction endonuclease digestion and electron microscopic analysis. 相似文献
13.
In higher plants, plastid and mitochondrial genomes occur at high copy numbers per cell. Several recent publications have
suggested that, in higher plants like Arabidopsis and maize, chloroplast DNA is virtually absent in mature and old leaves. This conclusion was mainly based on DAPI staining
of isolated chloroplasts. If correct, the finding that chloroplasts in mature leaves lack DNA would change dramatically our
understanding of gene expression, mRNA stability and protein stability in chloroplasts. In view of the wide implications that
the disposal of chloroplast DNA during leaf development would have, we have reinvestigated the age dependency of genome copy
numbers in chloroplasts and, in addition, tested for possible changes in mitochondrial genome copy number during plant development.
Analyzing chloroplast and mitochondrial DNA amounts in Arabidopsis and tobacco plants, we find that organellar genome copy numbers remain remarkably constant during leaf development and are
present in essentially unchanged numbers even in the senescing leaves. We conclude that, during leaf development, organellar
gene expression in higher plants is not significantly regulated at the level of genome copy number and we discuss possible
explanations for the failure to detect DNA in isolated chloroplasts stained with DAPI. 相似文献
14.
15.
A fusion between the plastid psbA promoter and the green fluorescent protein gene (gfp) was introduced into the tobacco chloroplast genome by stable plastid transformation. GFP was synthesized actively and exclusively in the chloroplasts. Tubular projections filled with GFP but containing no chlorophyll were visualized for the first time in chloroplasts of these transplastomic plants. Occasionally, the tubules connect chloroplasts with each other, suggesting the possibility of the exchange of endogenous proteins. However, the fusion of protoplasts between the transplastomic and wild-type plants showed that such chloroplast connections might be rare in mesophyll protoplasts. 相似文献
16.
17.
The Arabidopsis thaliana chloroplast protein ACCELERATED CELL DEATH2 (ACD2) modulates the amount of programmed cell death (PCD) triggered by Pseudomonas syringae and protoporphyrin IX (PPIX) treatment. In vitro, ACD2 can reduce red chlorophyll catabolite, a chlorophyll derivative. We find that ACD2 shields root protoplasts that lack chlorophyll from light- and PPIX-induced PCD. Thus, chlorophyll catabolism is not obligatory for ACD2 anti-PCD function. Upon P. syringae infection, ACD2 levels and localization change in cells undergoing PCD and in their close neighbors. Thus, ACD2 shifts from being largely in chloroplasts to partitioning to chloroplasts, mitochondria, and, to a small extent, cytosol. ACD2 protects cells from PCD that requires the early mitochondrial oxidative burst. Later, the chloroplasts of dying cells generate NO, which only slightly affects cell viability. Finally, the mitochondria in dying cells have dramatically altered movements and cellular distribution. Overproduction of both ACD2 (localized to mitochondria and chloroplasts) and ascorbate peroxidase (localized to chloroplasts) greatly reduces P. syringae-induced PCD, suggesting a pro-PCD role for mitochondrial and chloroplast events. During infection, ACD2 may bind to and/or reduce PCD-inducing porphyrin-related molecules in mitochondria and possibly chloroplasts that generate reactive oxygen species, cause altered organelle behavior, and activate a cascade of PCD-inducing events. 相似文献
18.
Inouye T Odahara M Fujita T Hasebe M Sekine Y 《Bioscience, biotechnology, and biochemistry》2008,72(5):1340-1347
RecA protein is widespread in bacteria, and it plays a crucial role in homologous recombination. We have identified two bacterial-type recA gene homologs (PprecA1, PprecA2) in the cDNA library of the moss Physcomitrella patens. N-terminal fusion of the putative organellar targeting sequence of PpRecA2 to the green fluorescent protein (GFP) caused a targeting of PpRecA2 to the chloroplasts. Mutational analysis showed that the first AUG codon acts as initiation codon. Fusion of the full-length PpRecA2 to GFP caused the formation of foci that were colocalized with chloroplast nucleoids. The amounts of PprecA2 mRNA and protein in the cells were increased by treatment with DNA damaging agents. PprecA2 partially complemented the recA mutation in Escherichia coli. These results suggest the involvement of PpRecA2 in the repair of chloroplast DNA. 相似文献
19.
Weilong Hao 《BMC bioinformatics》2010,11(1):114