Showing papers on "Ribosomal protein published in 1992"
428 citations
TL;DR: This work suggests that this ribosomal domain, involved in binding of aminoacyl-tRNA and GTP hydrolysis, has alternate conformers and proposes that the switch between the two configurations plays a role in translocation.
193 citations
TL;DR: The availability of reactive P peptide on the surface of cells makes possible the direct effect of autoantibodies on the function and viability of cells that express this antigenic target, delineates one of the possible impacts of anti-P antibodies in disease expression.
Abstract: Autoantibodies to ribosomal P-proteins are present in 12-16% of patients with systemic lupus erythematosus and are associated with neuropsychiatric disease. As the ribosomal P proteins are located in the cytoplasm, the pathogenic effects of their cognate autoantibodies are unclear. In this study affinity-purified anti-P autoantibodies were used to explore the cell surface of several types of human and animal cells. Immunofluorescence as well as EM immunogold analysis demonstrated, on the surface of human hepatoma cells, the presence of an epitope that is antigenically related to the immunodominant carboxy terminus of P-proteins. The presence of this epitope was also demonstrated on the surface of human neuroblastoma cells and, to a lesser extent, on human fibroblasts. Furthermore, the Western blot technique revealed in purified human and animal plasma membranes a 38-kD protein that is closely related or identical with ribosomal P0 protein. The availability of reactive P peptide on the surface of cells makes possible the direct effect of autoantibodies on the function and viability of cells that express this antigenic target. This delineates one of the possible impacts of anti-P antibodies in disease expression.
176 citations
TL;DR: Results reveal a regulatory function of this ribosomal protein in the hematopoietic system of Drosophila that may be related to its developmentally regulated phosphorylation.
Abstract: The tumor suppressor gene lethal(1)aberrant immune response 8 (air8) of Drosophila melanogaster encodes a homolog of the human S6 ribosomal protein. P element insertions that prevent expression of this gene cause overgrowth of the lymph glands (the hematopoietic organs), abnormal blood cell differentiation, and melanotic tumor formation. They also cause delayed development, inhibit growth of most of the larval organs, and lead to larval lethality. Mitotic recombination experiments indicate that the normal S6 gene is required for clone survival in the germ line and imaginal discs. The S6 gene produces a 1.1-kilobase transcript that is abundant throughout development in wild-type animals and in revertants derived from the insertional mutants but is barely detectable in the mutant larvae. cDNAs corresponding to this transcript show a 248-amino acid open reading frame with 75.4% identity and 94.8% similarity to both human and rat S6 ribosomal protein sequences. The results reveal a regulatory function of this ribosomal protein in the hematopoietic system of Drosophila that may be related to its developmentally regulated phosphorylation.
176 citations
TL;DR: The first crystal structure of a protein from the small ribosomal subunit, S5, is reported, which contains two distinct α/β domains that have structural similarities to several other proteins that are components of ribonucleoprotein complexes.
Abstract: UNDERSTANDING the process whereby the ribosome translates the genetic code into protein molecules will ultimately require high-resolution structural information, and we report here the first crystal structure of a protein from the small ribosomal subunit. This protein, S5, has a molecular mass of 17,500 and is highly conserved in all lifeforms1–4. The molecule contains two distinct α/β domains that have structural similarities to several other proteins that are components of ribonucleoprotein complexes. Mutations in S5 result in several phenotypes which suggest that S5 may have a role in translational fidelity and translocation. These include ribosome ambiguity or ram5, reversion from streptomycin dependence6 and resistance to spectinomycin6. Also, a cold-sensitive, spectinomycin-resistant mutant of S5 has been identified which is defective in initiation7. Here we show that these mutations map to two distinct regions of the molecule which seem to be sites of interaction with ribosomal RNA. A structure/function analysis of the molecule reveals discrepancies with current models8,9 of the 308 subunit.
157 citations
TL;DR: The vestigial plastid genome of Epifagus virginiana (beechdrops), a nonphotosynthetic parasitic flowering plant, is functional but lacks six ribosomal protein and 13 tRNA genes found in the chloroplast DNAs of photosynthetic flowering plants.
Abstract: The vestigial plastid genome of Epifagus virginiana (beechdrops), a nonphotosynthetic parasitic flowering plant, is functional but lacks six ribosomal protein and 13 tRNA genes found in the chloroplast DNAs of photosynthetic flowering plants. Import of nuclear gene products is hypothesized to compensate for many of these losses. Codon usage and amino acid usage patterns in Epifagus plastic genes have not been affected by the tRNA gene losses, though a small shift in the base composition of the whole genome (toward A + T -richness) is apparent. The ribosomal protein and tRNA genes that remain have had a high rate of molecular evolution, perhaps due to relaxation of constraints on the translational apparatus. Despite the compactness and extensive gene loss, one translational gene (infA, encoding initiation factor 1) that is a pseudogene in tobacco has been maintained intact in Epifagus.
141 citations
TL;DR: The SmD, SmP and SmR ribosomes have an enhanced GTP-hydrolysis idling reaction on EF-Tu, which is correlated with how aggressive proofreaders these ribosome are in steady-state assays, as well as mechanistic features of E. coli translation.
137 citations
TL;DR: The data support the idea that NSR1 is involved in the proper assembly of pre-rRNA particles, possibly by bringing rRNA and ribosomal proteins together by virtue of its nuclear localization sequence-binding domain and multiple RNA recognition motifs.
Abstract: NSR1 is a yeast nuclear localization sequence-binding protein showing striking similarity in its domain structure to nucleolin. Cells lacking NSR1 are viable but have a severe growth defect. We show here that NSR1, like nucleolin, is involved in ribosome biogenesis. The nsr1 mutant is deficient in pre-rRNA processing such that the initial 35S pre-rRNA processing is blocked and 20S pre-rRNA is nearly absent. The reduced amount of 20S pre-rRNA leads to a shortage of 18S rRNA and is reflected in a change in the distribution of 60S and 40S ribosomal subunits; there is no free pool of 40S subunits, and the free pool of 60S subunits is greatly increased in size. The lack of free 40S subunits or the improper assembly of these subunits causes the nsr1 mutant to show sensitivity to the antibiotic paromomycin, which affects protein translation, at concentrations that do not affect the growth of the wild-type strain. Our data support the idea that NSR1 is involved in the proper assembly of pre-rRNA particles, possibly by bringing rRNA and ribosomal proteins together by virtue of its nuclear localization sequence-binding domain and multiple RNA recognition motifs. Alternatively, NSR1 may also act to regulate the nuclear entry of ribosomal proteins required for proper assembly of pre-rRNA particles.
134 citations
TL;DR: It is proposed that MAK3 encodes an N-acetyltransferase whose modification of the L-A major coat protein NH2 terminus is essential for viral assembly, and that unassembled coat protein is unstable.
116 citations
TL;DR: Binding activity was similar in protein extracts made from resting and activated cells, suggesting that binding of the 56-kDa protein as measured in this assay is not regulated, and this protein is a member of what may be an emerging family of polyribopyrimidine-binding proteins with diverse biochemical functions.
94 citations
TL;DR: Mutations in rpsB that reduce the levels of the ribosomal protein S2 enhance the translation of cl in lambda lysogens, resulting in ternary complexes with the cl transcript more efficiently than wild-type subunits.
TL;DR: In this article, the authors examined the regulation of ribosomal protein (rp) gene expression in the developing and regenerating rat liver and found that the translation of rp mRNAs is selectively repressed by about 70% upon development from fetal to adult life.
Abstract: Mammalian liver development is accompanied by a transition from rapid growth in the fetus to a quiescent state in the adult. However, extensive proliferation can be induced in the adult liver by partial hepatectomy. In this study, we examined the regulation of ribosomal protein (rp) gene expression in the developing and regenerating rat liver. Our results indicate that the translation of rp mRNAs is selectively repressed by about 70% upon development from fetal to adult life, as illustrated by the decrease in ribosomal loading. In addition, the relative abundance of these mRNAs, like that of several other, but not all, housekeeping mRNAs, declines during development through a posttranscriptional mechanism. When liver cells commence growth following partial hepatectomy, translation of rp mRNAs is resumed to near-maximal capacity, as judged by their very efficient recruitment into polysomes. The concomitant increase in the abundance rp mRNAs under these circumstances is achieved by a posttranscriptional mechanism. The apparent fluctuations in the translation efficiency of rp mRNAs are accompanied by parallel changes in the expression of the genes encoding the initiation factors eIF-4E and eIF-4A. Our results indicate that selective translational control of rp mRNAs in mammals is not confined to manipulated cells in culture but constitutes an important regulatory mechanism operating in vivo in the course of liver development and regeneration.
TL;DR: This study sequenced this gene and found that the gene encodes a protein homologous to the L41 ribosomal protein of Saccharomyces cerevisiae, whose amino acid sequence has already been reported.
Abstract: Cycloheximide is one of the antibiotics that inhibit protein synthesis in most eukaryotic cells. We have found that a yeast, Candida maltosa, is resistant to the drug because it possesses a cycloheximide-resistant ribosome, and we have isolated the gene responsible for this. In this study, we sequenced this gene and found that the gene encodes a protein homologous to the L41 ribosomal protein of Saccharomyces cerevisiae, whose amino acid sequence has already been reported. Two genes for L41 protein, named L41a and L41b, independently present in the genome of S. cerevisiae, were isolated. L41-related genes were also isolated from a few other yeast species. Each of these genes has an intron at the same site of the open reading frame. Comparison of their deduced amino acid sequences and their ability to confer cycloheximide resistance to S. cerevisiae, when introduced in a high-copy-number plasmid, suggested that the 56th amino acid residue of the L41 protein determines the sensitivity of the ribosome to cycloheximide; the amino acid is glutamine in the resistant ribosome, whereas that in the sensitive ribosome is proline. This was confirmed by constructing a cycloheximide-resistant strain of S. cerevisiae having a disrupted L41a gene and an L41b gene with a substitution of the glutamine codon for the proline codon.
TL;DR: The result is a significant improvement of the coherent signal:noise ratio over traditional methods; due to this dilute solutions can be used, thus preventing unfavorable inter‐particle effects.
Abstract: Selected pairs of protonated ribosomal proteins were reconstituted into deuterated 50S subunits from Escherichia coli ribosomes. The rRNA of the deuterated ribosomal matrix was derived from cells grown in 76% D2O, the deuterated protein moiety from cells grown in 84% D2O. This procedure warrants that the coherent neutron scattering of deuterated proteins and rRNA is nearly the same and equals that of a D2O solution of approximately 90%. The neutron scattering is recorded in a reconstitution buffer containing approximately 90% D2O. The result is a significant improvement of the coherent signal:noise ratio over traditional methods; due to this dilute solutions can be used, thus preventing unfavorable inter-particle effects. From the diffraction pattern the distance between the mass centers of gravity of the two protonated proteins can be deduced. In this way, 50 distances between proteins within the large subunit have been determined which provide a basis for future models of the large ribosomal subunit describing the spatial distribution of the ribosomal proteins. A model containing seven ribosomal proteins is presented.
TL;DR: It is hypothesized that NusB binds to N-modified transcription complexes primarily by interacting with S10, a glutathione S-transferase-S10 fusion protein.
TL;DR: Several ribosomal proteins encoded by the liverworts mitochondrial genome differed substantially in size from their counterparts in E. coli and liverwort chloroplast.
Abstract: We detected 16 genes for ribosomal proteins in the complete sequence of the mitochondrial DNA from a liverwort, Marchantia polymorpha. The genes formed two major clusters, rps12-rps7 and rps10-rpl2-rps19-rps3-rpl16-rpl5- rps14-rps8- rpl6-rps13-rps11-rps1, very similar in organization to Escherichia coli ribosomal protein operons (str and S10-spc-alpha operons, respectively). In contrast, rps2 and rps4 genes were located separately in the liverwort mitochondrial genome (the latter was part of the alpha operon in E. coli). Furthermore, several ribosomal proteins encoded by the liverwort mitochondrial genome differed substantially in size from their counterparts in E. coli and liverwort chloroplast.
TL;DR: The authors showed that G-rich intergenic regions in the maxicircle of Leishmania tarentolae are conserved in location and polarity in two other kinetoplastid species.
Abstract: Six short G-rich intergenic regions in the maxicircle of Leishmania tarentolae are conserved in location and polarity in two other kinetoplastid species. We show here that G-rich region 6 (G6) represents a pan-edited cryptogene which contains at least two domains edited independently in a 3'-to-5' manner connected by short unedited regions. In the completely edited RNA, 117 uridines are added at 49 sites and 32 uridines are deleted at 13 sites, creating a translated 85-amino-acid polypeptide. Similar polypeptides are probably encoded by pan-edited G6 transcripts in two other species. The G6 polypeptide has significant sequence similarity to the family of S12 ribosomal proteins. A minicircle-encoded gRNA overlaps 12 editing sites in G6 mRNA, and chimeric gRNA/mRNA molecules were shown to exist, in agreement with the transesterification model for editing.
TL;DR: The presence of a strong SD sequence alone is able to substitute for at least part of the activities of ribosomal protein S1, and that ribosomes that exhibit S1 ‐independent translation on such messages also show less reliance on AUG as an initiation codon.
Abstract: We have designed a set of nine plasmids containing the Bacillus pumilis cat gene with one of three Shine-Dalgarno (SD) sequences (weak, strong or stronger) and one of three initiation codons (AUG, GUG or UUG). These constructions have been used to determine the effect of ribosomal protein S1, SD and initiation codon sequences and Escherichia coli ribosomal protein S1 on translation in vitro by E. coli and B. subtilis ribosomes. Translation of these nine constructions was determined with three types of ribosomes: E. coli containing ribosomal protein S1, E. coli depleted of S1, and B. subtilis which is naturally free of S1. E. coli ribosomes were able to translate all nine transcripts with variable efficiencies. B. subtilis and S1-depleted E. coli ribosomes were similar to each other and differed from non-depleted E. coli ribosomes in that they required strong or stronger SD sequences and were unable to translate any of the weak transcripts. Addition of S1 from either E. coli or Micrococcus luteus, a Gram-positive bacterium, enabled S1-depleted E. coli ribosomes to translate mRNAs with weak SD sequences but had no effect on B. subtilis ribosomes. AUG was the preferred initiation codon for all ribosome types; however, B. subtilis ribosomes showed greater tolerance for the non-AUG codons than either type of E. coli ribosome. The presence of a strong or stronger SD sequence increased the efficiency by which E. coli ribosomes could utilize non-AUG codons.(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: This work shows that L20 directly represses the expression of rpmI, and indirectly that of rplT, via translational coupling with rpmI through the formation of secondary structures that sequester internal ribosomal binding sites, the first time that such a structure has been shown to exist.
TL;DR: In situ hybridization experiments demonstrated that expression of this gene was elevated in histological sections of human premalignant leukoplakia, head and neck squamous cell carcinomas, and colon and breast cancers compared with the adjacent normal tissues, and may be a useful diagnostic or prognostic marker for grading human tumors.
Abstract: Differential screening of a cDNA library was used to isolate genes differentially expressed in a nontumorigenic clone and a ras-transformed variant of the human teratocarcinoma cell line PA-1. The RNA transcript for one of the cDNA clones that we identified was expressed at a 25-fold higher level in the ras-transformed PA-1 cells than in the nontumorigenic PA-1 cells. DNA sequence analysis of this clone showed that it had 86% nucleic acid homology to the mouse LLRep3 gene and only differed at a single amino acid codon (codon 198), which is changed from serine in LLRep3 to threonine in this cDNA clone. The rat ribosomal S2 protein is closely related to the yeast omnipotent informational suppressor SUP44, which encodes the yeast ribosomal protein S4; to the mouse protein LLRep3; and to the human cDNA clone we describe in this report. We therefore concluded that this clone codes for the human ribosomal S2 protein. In situ hybridization experiments revealed that expression of this gene was elevated in cultured human head and neck squamous cell carcinomas compared with normal keratinocytes. In situ hybridization experiments also demonstrated that expression of this gene was elevated in histological sections of human premalignant leukoplakia, head and neck squamous cell carcinomas, and colon and breast cancers compared with the adjacent normal tissues. S2 expression may be a useful diagnostic or prognostic marker for grading human tumors.
TL;DR: With the results presented here, there are now published sequences for 14 yeast mitochondrial ribosomal proteins, only five of which bear discernable relationships to eubacterial ribosome proteins.
TL;DR: The result suggests that the 30S P site contains a pocket that becomes inaccessible to the Fe(2+)-EDTA complex when tRNA is bound, whose minimum dimensions can be inferred from the boundaries of the protected region of tRNA.
Abstract: Hydroxyl radical is a useful probe of the accessibility of the sugar moiety of nucleic acids to solvent. Here we compare the accessibility of free and ribosome-bound yeast tRNA(Phe), Escherichia coli tRNA(Phe), and E. coli tRNA(Leu2) to attack by hydroxyl radicals generated from Fe(2+)-EDTA. When bound to the P site of 30S ribosomal subunits, a discrete region, corresponding almost precisely to the anticodon stem-loop, is strongly protected; weaker protection is observed in the 3' strand of the D stem and in the variable loop. The protected nucleotides constitute a well-defined substructure, corresponding to the lower half of the anticodon-D loop coaxial arm of the tRNA crystal structure. This result suggests that the 30S P site contains a pocket that becomes inaccessible to the Fe(2+)-EDTA complex when tRNA is bound, whose minimum dimensions can be inferred from the boundaries of the protected region of tRNA. When bound to the P site of 70S ribosomes, the entire tRNA backbone becomes inaccessible to hydroxyl radicals. Since previous studies have shown that virtually the entire footprint of a P-site tRNA on 16S and 23S rRNAs is mimicked by the extremities of the tRNA (the anticodon stem-loop plus the 3'-terminal aminoacyl-pentanucleotide), protection of the entire tRNA was unexpected. We conclude that protection of the elbow of tRNA is due either to interactions with ribosomal proteins or to enclosure in an inaccessible site formed by association of the two ribosomal subunits.
TL;DR: Results indicate that P proteins and L12 bind to restricted sites in the GTPase domain and that the complex constitutes the G TPase-related functional site in mammalian ribosomes.
TL;DR: In this paper, a negative control element located between codons 18 and 50 of 21K was found to prevent the formation of the mRNA secondary structure over both the Shine-Dalgarno (SD) sequence and the start codon.
TL;DR: The results obtained show that the change in ribosomal protein mRNA localization is very fast, allowing short-term adjustments of ribosome synthesis rate, consistent with the hypothesis that the amount of free ribosomes present in the cell could affect ribosom protein mRNA utilization.
Abstract: Translational control of ribosomal protein mRNA was analyzed in a Xenopus cell line during growth-rate changes induced by serum deprivation and readdition. After being transferred into serum-free medium, the cells rapidly decrease their DNA, RNA and protein synthesis, while addition of serum to the culture after a few hours of deprivation causes a rapid recovery. During these growth-rate changes, we observed a shift in ribosomal protein mRNA distribution between polysomes and RNP. The proportion of mRNA on polysomes for the four ribosomal proteins analyzed changed from 70-80% during rapid growth to 25-35% during the downshift and back to 70-80% after the upshift. Northern blot analysis showed that ribosomal protein mRNA level was constant during the shifts even in the presence of the transcriptional inhibitor actinomycin D. This indicates that the distribution changes were due to a reversible transfer of ribosomal protein mRNA between polysomes and RNP without altering mRNA stability. We have also compared the kinetics of ribosomal protein mRNA distribution changes with the kinetics of the changes in the partition of ribosomes between free monomers and polysomes. The results obtained show that the change in ribosomal protein mRNA localization is very fast, allowing short-term adjustments of ribosome synthesis rate. Moreover, our observations are consistent with the hypothesis that the amount of free ribosomes present in the cell could affect ribosomal protein mRNA utilization.
TL;DR: It is shown that fau (for FBR-MuSV associated ubiquitiously expressed gene) becomes expressed in all different tissues tested as a 600 bp messenger and the genomic structure of the human fau gene is reported.
TL;DR: Three putative but potentially important regulatory sequences were identified within this operon: an L1 translational control site, a transcription attenuator, and a strong rho-independent terminator.
TL;DR: The phenotype of cells carrying a disrupted copy of MRP4 is consistent with the MRP3 protein being an essential component of the mitochondrial protein synthetic machinery and regions of sequence similarity with the mammalian 68-kDa high affinity laminin receptor are noted.
TL;DR: Using a mutant of Saccharomyces cerevisiae defective in the NAT1 gene, that encodes one of the NH2-terminal acetyltransferases, it is identified 14 ribosomal proteins whose electrophoretic mobility at pH 5.0 suggests they carry an additional charge, presumably due to the lack of NH1-terminally acetylation.
TL;DR: Xenopus S6 closely resembled mammalian S6 with respect to the following properties: reversed-phase HPLC elution behavior, amino-terminal sequence (96% identity in the first 37 residues), and an identical sequence within the region of its phosphorylation sites.