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At least 19 recordsLinked to original sources

Cloning and analysis of the nuclear gene MRP-S9 encoding mitochondrial ribosomal protein S9 of Saccharomyces cerevisiae.

The Saccharomyces cerevisiae nuclear gene MRP-S9 was identified as part of the European effort in sequencing chromosome II. MRP-S9 encodes for a hydrophilic and basic protein of 278 amino acids with a molecular mass of 32 kDa. The C-terminal part (aa 153-278) of the MRP-S9 protein exhibits significant sequence similarity to members of the eubacterial and chloroplast S9 ribosomal-protein family. Cells disrupted in the chromosomal copy of MRP-S9 were unable to respire and displayed a characteristic phenotype of mutants with defects in mitochondrial protein synthesis as indicated by a loss of cytochrome c oxidase activity. Additionally, no activities of the gluconeogenetic enzymes, fructose-1,6-bisphosphatase and phosphoenolpyruvate carboxykinase, could be observed under conditions of glucose de-repression. The respiration-deficient phenotype could not be restored by transformation of the disruption strain with a wild-type copy of MRP-S9, indicating that MRP-S9 disruption led to rho- or rho0 cells. Sequence similarities of MRP-S9 to other members of the ribosomal S9-protein family and the phenotype of disrupted cells are consistent with an essential role of MRP-S9 is assembly and/or function of the 30s subunit of yeast mitochondrial ribosomes.

Amino Acid Sequence↗

cDNA cloning and gene expression of ribosomal S9 protein gene in the mollusk Corbicula fluminea: a new potential biomarker of metal contamination up-regulated by cadmium and repressed by zinc.

Biological indicators can be used to assess polluted sites, but their success depends on their specificity. The aim of the present study was to identify a specific cadmium biomarker of the freshwater bivalve Corbicula fluminea. Differential display technique was used to identify new molecular indicators for cadmium exposure. Gene expression of C. fluminea transplanted into a cadmium- and zinc-contaminated river was compared to gene expression of bivalves from a reference site. One differentially expressed band was identified, and the entire cDNA sequence coding for the ribosomal protein S9 (rpS9) was cloned. The rpS9 gene expression was studied by real-time reverse transcription-polymerase chain reaction. After controlled cadmium (15 microg/L) and/or zinc (1 mg/L) laboratory contaminations of the bivalves, this gene was shown to be up-regulated by cadmium and down-regulated by zinc. A 48-d transplantation of animals into a polymetallic field contamination in the Lot river basin (Midi-Pyrénées region, France) showed that rpS9 gene regulation was correlated with the fluctuating cadmium and zinc water contents. To our knowledge, the existence of a gene that is up-regulated by cadmium and repressed by zinc is demonstrated here for the first time.

Amino Acid Sequence↗

A mutation in the nuclear-encoded plastid ribosomal protein S9 leads to early embryo lethality in maize.

Seeds of the lethal embryo 1 (lem1) mutant in maize (Zea mays) display a non-concordant lethal phenotype: whereas the embryo aborts very early, before the transition stage, the endosperm develops almost normally. The mutant was identified in a collection of maize lines that carried the transposon Activation (Ac) at different locations in the genome. Co-segregation and reversion analysis showed that lem1 was tagged by Ac. The lem1 gene encodes a protein that is highly similar to the rice plastid 30S ribosomal protein S9 (PRPS9). lem1 maps to chromosome 1L and appears to be the only copy of prps9 in the maize genome. Green fluorescent protein (GFP) fusion constructs containing only the putative transit peptide (TP) of LEM1 localize exclusively to the plastids, confirming that the LEM1 protein is a PRP. In contrast, GFP fusion constructs containing the entire LEM1 protein co-localize to the plastids and to the nucleus, suggesting a possible dual function for this protein. Two alternative, although not mutually exclusive, explanations are considered for the lem phenotype of the lem1 mutant: (i) functional plastids are required for normal embryo development; and (ii) the PRPS9 has an extra-ribosomal function required for embryogenesis.

Amino Acid Sequence↗

Identification of the structural gene for the S9 ribosomal protein in the fungus Podospora anserina: a new protein involved in the control of translational accuracy.

AS9-1 was isolated as a mutation restoring growth in a strain carrying the ribosomal mutation su12-1. The AS9-1 mutation confers a weak antisuppressor effect and a low level of resistance to paromomycin. Two-dimensional polyacrylamide gel electrophoresis patterns of the ribosomal proteins from AS9-1 strains show an altered S9 protein which is more basic than the wild-type form. The presence of the two forms of the protein (wild-type and mutant) in heterocaryotic strains strongly suggests that AS9 is the structural gene for the ribosomal protein S9.

Ascomycota↗

A novel plant nuclear gene encoding chloroplast ribosomal protein S9 has a transit peptide related to that of rice chloroplast ribosomal protein L12.

We have cloned a novel nuclear gene for a ribosomal protein of rice and Arabidopsis that is like the bacterial ribosomal protein S9. To determine the subcellular localization of the gene product, we fused the N-terminal region and green fluorescent protein and expressed it transiently in rice seedlings. Localized fluorescence was detectable only in chloroplasts, indicating that this nuclear gene encodes chloroplast ribosomal protein S9. The N-terminal region of rice ribosomal protein S9 was found to have a high sequence similarity to the transit peptide region of the rice chloroplast ribosomal protein L12, suggesting that these transit peptides have a common lineage.

Amino Acid Sequence↗

Over-expression of Candida albicans mitochondrial ribosomal protein S9 (MrpS9p) disturbs mitochondrial function in Saccharomyces cerevisiae.

A Candida albicans mitochondrial ribosomal protein S9 (MRPS9) cDNA was identified in a screen for sequences whose expression induce galactose lethality in Saccharomyces cerevisiae. MRPS9 appears to encode a protein of 346 amino acids with an N-terminal mitochondrial targeting sequence and an internal S9 signature that is conserved amongst eukaryotic mitochondrial and prokaryotic ribosomal protein S9 sequences. Expression of a GAL1-CaMRPS9 fusion in S. cerevisiae caused the slow development of a galactose-negative phenotype upon repeated subculturing, and this correlated with an increased frequency of petite mutant formation. Therefore, over-expression of CaMRPS9 interferes with S. cerevisiae mitochondrial function, which accounts for the inhibition of growth on galactose.

Amino Acid Sequence↗

Cloning, sequencing, expression, and functional studies of a 15,000-molecular-weight Haemophilus somnus antigen similar to Escherichia coli ribosomal protein S9.

Haemophilus somnus is a gram-negative bacterium capable of causing a number of disease syndromes in cattle. This article describes the cloning and characterization of a gene coding for a 15,000-molecular-weight (15K) polypeptide which reacts strongly with antiserum against H. somnus. Analysis of plasmid-encoded polypeptides by polyacrylamide gel electrophoresis showed that the corresponding gene is the second in a transcriptional unit. The first gene codes for a protein with a molecular weight of approximately 17,000. Using antiserum against the two recombinant proteins, we could show that the natural proteins are predominantly present in purified ribosomes from H. somnus. The nucleotide sequence of both genes and flanking regions has been determined, and the deduced amino acid sequence of the two polypeptides was used to search for sequence homology in the GenBank data base. The 15K polypeptide showed 89% similarity to the Escherichia coli ribosomal protein S9, and the 17K polypeptide showed 94% similarity to the E. coli ribosomal protein L13. In E. coli, the corresponding genes constitute a bicistronic operon, with the same gene order as that found in H. somnus. A plasmid expressing the 15K protein was found to complement an E. coli rpsI mutation. When a frameshift mutation was introduced into the 15K protein gene, the resulting plasmid failed to complement this rpsI mutation, demonstrating functional homology between the 15K protein and S9 from E. coli. Downstream from the 15K protein gene is located another open reading frame, which could code for a polypeptide with a predicted molecular weight of 24,427. A protein with a similar molecular weight was detected in minicells containing the recombinant clone. This polypeptide is 69% similar to the stringent starvation protein (Ssp) of E. coli.

Amino Acid Sequence↗

The primary structure of rat ribosomal protein S9.

The amino acid sequence of the rat 40S ribosomal subunit protein S9 was deduced from the sequence of nucleotides in a recombinant cDNA. Ribosomal protein S9 has 193 amino acids, the NH2-terminal methionine is removed after translation of the mRNA, and has a molecular weight of 22,360. Hybridization of the cDNA to digests of nuclear DNA suggests that there are 14 to 16 copies of the S9 gene. The mRNA for the protein is about 1,000 nucleotides in length in part because of an especially long 5' noncoding region (103 nucleotides). Rat S9 is related to ribosomal proteins from other eukaryotes, Saccharomyces cerevisiae YS11 and Dictyostelium discoideum rp 1024, and to the eubacterial, archaebacterial, and chloroplast family of S4 ribosomal proteins. We have identified the product of the Trypanosoma brucei gene U as the homolog of rat ribosomal protein S9.

Amino Acid Sequence↗

Ribosomal proteins S9 and L6 participate in the binding of [3H]dibekacin to E. coli ribosomes.

The degrees of binding of [3H]dibekacin to LiCl-treated cores of E. coli ribosomes were reduced by increasing LiCl concentrations. The 1.15 M LiCl core lost 70 approximately 80% of the original binding capacity. The antibiotic attachment to the 1.15 M LiCl core was restored by reconstitution with the split proteins (SP), which were obtained by the treatment of 70S ribosomes with LiCl at concentrations of 0.8 approximately 1.15 M. The basic proteins, split off during the transition from 0.4 M LiCl core to 0.8 approximately 1.15 M LiCl core, seemed to be involved in the drug binding. SP0.4 approximately 1.15, which was obtained by the treatment of the 0.4 M LiCl core with 1.15 M LiCl, was fractionated by CM-Sephadex C-25 column chromatography, and each fraction was assayed for protein composition and the capability of restoring the ability of the 1.15 M LiCl core to bind the drug. Of ribosomal proteins eliminated with 1.15 M LiCl, the addition of either S9 or L6 alone to the 1.15 M LiCl core was observed to restore approximately 50% of the binding as compared to the 70S ribosome alone, and both proteins restored about 70% of the binding. The results suggested that ribosomal proteins S9 and L6 were involved in the attachment of [3H]dibekacin to the ribosome. The antibiotic binding to the 70S ribosome and 1.15 M LiCl core reconstituted with S9 and L6 was considerably inhibited by unlabelled dibekacin or kanamycin, and partially inhibited by gentamicin or neomycin, but was not significantly affected by streptomycin or viomycin.

Aminoglycosides↗

Recovery of cDNAs encoding ribosomal proteins S9 and L26 from Aedes albopictus mosquito cells and identification of their homologs in the malaria vector, Anopheles gambiae.

We used PCR-based approaches to obtain the full-length cDNA sequences encoding ribosomal protein (Rp) S9 and L26 from a mosquito (Aedes albopictus) C7-10 cell line. The deduced mosquito RpS9 protein has a mass of 22,826 Da and a pI of 11.41, while RpL26 had a mass of 17,442 Da and a pI of 11.52. Both cDNAs initiated with the 5'-polypyrimidine motif characteristic of ribosomal protein transcripts. Using the Aedes protein and nucleic acid sequences, we identified rpS9 and rpL26 as single copy genes in the Anopheles gambiae genome. In An. gambiae, the RpS9 coding region was distributed over 3 exons, spanning 2.6 kb, but the Anopheles rpL26 protein coding region lacked introns. The Aedes and Anopheles RpS9 and RpL26 proteins shared 96 and 92% identity, respectively. Despite low numbers of parsimony-informative amino acid substitutions, phylogenies based on the ribosomal protein sequences accurately group the Aedes and Anopheles proteins with high bootstrap values.

Aedes↗

Cloning and nucleotide sequencing of the genes for ribosomal proteins S9 (rpsI) and L13 (rplM) of Escherichia coli.

The genes for the ribosomal proteins S9 (rpsI) and L13 (rplM) of Escherichia coli have been cloned into a lambda phage vector termed L47.1. The two genes were identified by infecting UV-light irradiated cells with the resultant phages and analyzing the protein products by two-dimensional gel electrophoresis. Suitable DNA fragments of the isolate were cloned subsequently into M13 phage vectors and their nucleotide sequence was determined by the dideoxy method. It is evident that the two genes form a transcriptional unit, the rplM gene being promoter-proximal. There is a typical signal sequence for transcriptional termination after the rpsI gene. The codon usage pattern in the two genes is similar to other ribosomal protein genes of E. coli.

Amino Acid Sequence↗

Alterations in mRNA expression of ribosomal protein S9 in hydrogen peroxide-treated neurotumor cells and in rat hippocampus after transient ischemia.

This study was designed to isolate new genes related to apoptosis in rat pheochromocytoma (PC12) cells treated with hydrogen peroxide (H2O2), and to characterize the roles of the genes using both in vitro and in vivo models of oxidative injury. cDNA libraries were prepared from H2O2-treated and -untreated PC12 cells, and a ribosomal protein S9 (RPS9) clone was isolated by a differential screening method. Increase of RPS9 expression in both H2O2-treated PC12 and neuroblastoma (Neuro-2A) cells was shown by Northern blot analysis. Viability of the antisense-transfected Neuro-2A (RPS9-AS) cells following H2O2 treatment was significantly reduced in a dose-dependent manner. In an in vivo model of transient forebrain ischemia, an increase in RPS9 expression was prominent by 1 day postischemia in the granule cell layer neurons of the dentate gyrus. Both activation of caspase-3 and significant recovery of viability following pretreatment with cycloheximide were shown in RPS9-AS cells treated with H2O2. These data suggest that RPS9 plays a protective role in oxidative injury of neuronal cells.

Adrenal Gland Neoplasms↗

Influence of correct secondary and tertiary RNA folding on the binding of cellular factors to the HCV IRES.

Structural integrity of the hepatitus C virus (HCV) 5' UTR region that includes the internal ribosome entry site (IRES) element is known to be essential for efficient protein synthesis. The functional explanation for this observation has been provided by the recent evidence that binding of several cellular factors to the HCV IRES is dependent on the conservation of its secondary structure. In order to better define the relationship between IRES activity, protein binding and RNA folding of the HCV IRES, we have focused our attention on its major stem-loop region (domain III) and the binding of several cellular factors: two subunits of eukaryotic initiation factor eIF3 and ribosomal protein S9. Our results show that binding of eIF3 p170 and p116/p110 subunits is dependent on the ability of the domain III apical stem-loop region to fold in the correct secondary structure whilst secondary structure of hairpin IIId is important for the binding of S9 ribosomal protein. In addition, we show that binding of S9 ribosomal protein also depends on the disposition of domain III on the HCV 5' UTR, indicating the presence of necessary inter-domain interactions required for the binding of this protein (thus providing the first direct evidence that tertiary folding of the HCV RNA does affect protein binding).

Animals↗

Analysis of targeting sequences demonstrates that trafficking to the Toxoplasma gondii plastid branches off the secretory system.

Apicomplexan parasites possess a plastid-like organelle called the apicoplast. Most proteins in the Toxoplasma gondii apicoplast are encoded in the nucleus and imported post-translationally. T. gondii apicoplast proteins often have a long N-terminal extension that directs the protein to the apicoplast. It can be modeled as a bipartite targeting sequence that contains a signal sequence and a plastid transit peptide. We identified two nuclearly encoded predicted plastid proteins and made fusions with green fluorescent protein to study protein domains required for apicoplast targeting. The N-terminal 42 amino acids of the apicoplast ribosomal protein S9 directs secretion of green fluorescent protein, indicating that targeting to the apicoplast proceeds through the secretory system. Large sections of the S9 predicted transit sequence can be deleted with no apparent impact on the ability to direct green fluorescent protein to the apicoplast. The predicted transit peptide domain of the S9 targeting sequence directs protein to the mitochondrion in vivo. The transit peptide can also direct import of green fluorescent protein into chloroplasts in vitro. These data substantiate the model that protein targeting to the apicoplast involves two distinct mechanisms: the first involving the secretory system and the second sharing features with typical chloroplast protein import.

Amino Acid Sequence↗

Probing the assembly of the 3' major domain of 16 S ribosomal RNA. Quaternary interactions involving ribosomal proteins S7, S9 and S19.

We have studied the effect of assembly of ribosomal proteins S7, S9 and S19 on the accessibility and conformation of nucleotides in 16 S ribosomal RNA. Complexes formed between 16 S rRNA and S7, S7 + S9, S7 + S19 or S7 + S9 + S19 were subjected to a combination of chemical and enzymatic probes, whose sites of attack in 16 S rRNA were identified by primer extension. The results of this study show that: (1) Protein S7 affects the reactivity of an extensive region in the lower half of the 3' major domain. Inclusion of proteins S9 or S19 with S7 has generally little additional effect on S7-specific protection of the RNA. Clusters of nucleotides that are protected by protein S7 are localized in the 935-945 region, the 950/1230 stem, the 1250/1285 internal loop, and the 1350/1370 stem. (2) Addition of protein S9 in the presence of S7 causes several additional effects principally in two structurally distal regions. We observe strong S9-dependent protection of positions 1278 to 1283, and of several positions in the 1125/1145 internal loop. These findings suggest that interaction of protein S9 with 16 S rRNA results in a structure in which the 1125/1145 and 1280 regions are proximal to each other. (3) Most of the strong S19-dependent effects are clustered in the 950-1050 and 1210-1230 regions, which are joined by base-pairing in the 16 S rRNA secondary structure. The highly conserved 960-975 stemp-loop, which has been implicated in tRNA binding, appears to be destabilized in the presence of S19. (4) Protein S7 causes enhanced reactivity at several sites that become protected upon addition of S9 or S19. This suggests that S7-induced conformational changes in 16 S rRNA play a role in the co-operativity of assembly of the 3' major domain.

Aldehydes↗

Protein binding sites on Escherichia coli 16S RNA; RNA regions that are protected by proteins S7, S14 and S19 in the presence or absence of protein S9.

14C-labelled proteins from E. coli 30S ribosomal subunits were isolated by HPLC, and selected groups of these proteins were reconstituted with 32P-labelled 16S RNA. The isolated reconstituted particles were partially digested with ribonuclease A, and the RNA fragments protected by the proteins were separated by gel electrophoresis and subjected to sequence analysis. Protein S7 alone gave no protected fragments, but S7 together with S14 and S19 protected an RNA region comprising the sequences 936-965, 972-1030, 1208-1262 and 1285-1379 of the 16S RNA. Addition of increasing amounts of protein S9 to the S7/S14/S19 particle resulted in a parallel increase in the protection of the hairpin loop between bases 1262 and 1285. The results are discussed in terms of the three-dimensional folding of 16S RNA in the 30S subunit.

Bacterial Proteins↗

Sequence determination of protein S9 from the Escherichia coli ribosome.

The complete amino acid sequence of ribosomal protein S9 of Escherichia coli has been established. The protein was digested with trypsin and Staphylococcus aureus protease and the resulting peptides were separated by ion exchange chromatography on a new Dowex 50W-X7 microcolumn or a small phosphocellulose column. If necessary, they were rechromatographed on purified cellulose thin-layer plates on a preparative scale. The sequences of the peptides were determined by the micro dansyl-Edman technique, whereas the alignments of the tryptic peptides were mainly established from large cyanogen bromide fragments which were sequenced by the automatic Edman degradation process. Protein S9 is 128 amino acids long and has the following composition: Asx7, Thr5, Ser7, Glx16, Pro3, Gly13, Ala10, Val10, Met3, Ile7, Leu9, Tyr5, Phe4, His1, Lys10, Arg18. The molecular weight as calculated from the amino acid composition is 14 569. A total of 92.6 mg of the lyophilized protein was used for the determination of the primary structure of S9. Most of the material was needed to isolate sufficient amounts of the CNBr-fragments for the automatic degradation in the sequenator.

Amino Acid Sequence↗

Ribosomal protein S5 interacts with the internal ribosomal entry site of hepatitis C virus.

Translational initiation of hepatitis C virus (HCV) genome RNA occurs via its highly structured 5' noncoding region called the internal ribosome entry site (IRES). Recent studies indicate that HCV IRES and 40 S ribosomal subunit form a stable binary complex that is believed to be important for the subsequent assembly of the 48 S initiation complex. Ribosomal protein (rp) S9 has been suggested as the prime candidate protein for binding of the HCV IRES to the 40 S subunit. RpS9 has a molecular mass of approximately 25 kDa in UV cross-linking experiments. In the present study, we examined the approximately 25-kDa proteins of the 40 S ribosome that form complexes with the HCV IRES upon UV cross-linking. Immunoprecipitation with specific antibodies against two 25-kDa 40 S proteins, rpS5 and rpS9, clearly identified rpS5 as the protein bound to the IRES. Thus, our results support rpS5 as the critical element in positioning the HCV RNA on the 40 S ribosomal subunit during translation initiation.

5' Untranslated Regions↗