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At least 523 records · Page 29Linked to original sources
PubMed2002

survivin messenger RNA expression is a good prognostic biomarker for oesophageal carcinoma.

Oesophageal squamous cell carcinoma is one of the most malignant tumours. To identify patients with a high risk of recurrence of oesophageal squamous cell carcinoma, we investigated the prognostic significance of survivin mRNA expression in oesophageal squamous cell carcinoma, which has recently been reported to be a good marker for unfavourable prognosis in various tumours. Tumours and non-cancerous epitheliums adjacent to tumours were obtained by surgical resection from 57 patients with oesophageal squamous cell carcinoma. Expression levels of survivin and glyceraldehyde-3-phosphate dehydrogenase mRNA were analysed quantitatively by real-time reverse transcriptase polymerase chain reaction (RT-PCR). The survivin/glyceraldehyde-3-phosphate dehydrogenase ratios of tumours were higher than those of non-cancerous tissues (P=0.0003). Tumour-survivin/glyceraldehyde-3-phosphate dehydrogenase ratio did not correlate with histologic type, lymph node metastasis, and stage of tumours. In 53 surviving patients, the 5-year survival rate of 17 patients with high survivin mRNA expressed oesophageal squamous cell carcinoma (14.1%) was significantly poorer than that of 36 with low survivin mRNA expressed oesophageal squamous cell carcinoma (46.8%, P=0.0018). In these patients, tumour-survivin mRNA expression was recognised as a good marker of cancer recurrence independently from tumour stage. These findings indicate that survivin mRNA expression in oesophageal squamous cell carcinoma may be a good biomarker for identifying patients with high risk of cancer recurrence.

Aged↗
PubMed2004

Hfq, a new chaperoning role: binding to messenger RNA determines access for small RNA regulator.

The Sm-like protein Hfq is involved in post-transcriptional regulation by small, noncoding RNAs in Escherichia coli that act by base pairing. Hfq stabilises the small RNAs and mediates their interaction with the target mRNA by an as yet unknown mechanism. We show here a novel chaperoning use of Hfq in the regulation by small RNAs. We analysed in vitro and in vivo the role of Hfq in the interaction between the small RNA RyhB and its sodB (iron superoxide dismutase) mRNA target. Hfq bound strongly to sodB mRNA and altered the structure of the mRNA, partially opening a loop. This gives access to a sequence complementary to RyhB and encompassing the translation initiation codon. RyhB binding blocked the translation initiation codon of sodB and triggered the degradation of both RyhB and sodB mRNA. Thus, Hfq is a critical chaperone in vivo and in vitro, changing the folding of the target mRNA to make it subject to the small RNA regulator.

Bacterial Proteins↗
PubMed2001

Visualization of protein S1 within the 30S ribosomal subunit and its interaction with messenger RNA.

S1 is the largest ribosomal protein, present in the small subunit of the bacterial ribosome. It has a pivotal role in stabilizing the mRNA on the ribosome. Thus far, S1 has eluded structural determination. We have identified the S1 protein mass in the cryo-electron microscopic map of the Escherichia coli ribosome by comparing the map with a recent x-ray crystallographic structure of the 30S subunit, which lacks S1. According to our finding, S1 is located at the junction of head, platform, and main body of the 30S subunit, thus explaining all existing biochemical and crosslinking data. Protein S1 as identified in our map has a complex, elongated shape with two holes in its central portion. The N-terminal domain, forming one of the extensions, penetrates into the head of the 30S subunit. Evidence for direct interaction of S1 with 11 nucleotides of the mRNA, immediately upstream of the Shine-Dalgarno sequence, explains the protein's role in the recognition of the 5' region of mRNA.

Cryoelectron Microscopy↗
PubMed1972

Formation of a mammalian initiation complex with reovirus messenger RNA, methionyl-tRNA F , and ribosomal subunits.

Previous data demonstrated that reovirus mRNA, synthesized in vitro with the particulate RNA transcriptase of reovirus cores, efficiently directs the synthesis of polypeptides in vitro. The present studies indicate that all of the three size classes of reovirus mRNA produced in vitro can form protein initiation complexes with rat liver [(36)S]Met-tRNA(F) and incubated 40S and 60S ribosomal subunits, which had been washed in 0.5 M KCl of mouse fibroblast L-929 cells. Mild prior treatment of the mRNA with HCHO was required to expose the initiator region. The initiation complex reacted quantitatively with puromycin to form a puromycin peptide, whose electrophoretic properties were identical to methionyl-puromycin formed in response to poly(A,G,U) or the initiator codon AUG. The complex was relatively stable and specific for [(35)S]Met-tRNA(F); rat liver [(35)S]Met-tRNA(M) was unreactive unless the supernatant factors EF T(1) and EF T(2) were also present. However, the addition of fusidic acid, at a concentration that did not affect complex formation with [(35)S]Met-tRNA(F), completely inhibited Met-tRNA(M) utilization. Exogenous ribosomal factors and GTP were not required unless the separated 40S and 60S subunits were further treated with 1 M KCl. The data suggest that reovirus mRNA contains AUG initiator codons that form a complex with Met-tRNA(F) at a puromycin-reactive site on ribosomes.

Animals↗
PubMed1972

Increased efficiency of exogenous messenger RNA translation in a Krebs ascites cell lysate.

Addition of a 0.5 M KCl wash fraction from rabbit reticulocyte ribosomes causes a 3- to 10-fold increase in the extent of translation of natural mRNAs by Krebs-cell lysates. In the presence of the wash fraction, 1 pmol of rabbit or mouse 10S RNA directs the incorporation of 80 pmol of leucine into rabbit globin. The addition of human 10S RNA results in the synthesis of equal amounts of human alpha and beta chains, identified by column chromatography. The stimulation by the wash fraction is almost completely dependent on added mammalian tRNA. In contrast to the wash fraction from rabbit reticulocytes, the wash fraction isolated from Krebs-cell ribosomes is inhibitory to both endogenous and exogenous mRNA translation. The stimulation by the wash fraction from rabbit ribosomes is not specific for globin mRNAs, but also increases endogenous, phage Qbeta, and viral RNA-directed protein synthesis.

Amino Acyl-tRNA Synthetases↗
PubMed1972

Purification of biologically active globin messenger RNA by chromatography on oligothymidylic acid-cellulose.

A convenient technique for the partial purification of large quantities of functional, poly(adenylic acid)-rich mRNA is described. The method depends upon annealing poly(adenylic acid)-rich mRNA to oligothymidylic acid-cellulose columns and its elution with buffers of low ionic strength. Biologically active rabbit globin mRNA has been purified by this procedure and assayed for its ability to direct the synthesis of rabbit globin in a cell-free extract of ascites tumor. Inasmuch as various mammalian mRNAs appear to be rich in poly(adenylic acid) and can likely be translated in the ascites cell-free extract, this approach should prove generally useful as an initial step in the isolation of specific mRNAs.

Acrylamides↗
PubMed1972

Correlation of messenger RNA function with adenylate-rich segments in the genomes of single-stranded RNA viruses.

Oligonucleotides enriched in adenylate residues have been demonstrated in the genomes of two positive-strand RNA viruses, Sindbis and Columbia SK. Such oligonucleotides were not found in the genome of vesicular stomatitis virus, a negative-strand virus. The adenylate-rich oligonucleotides from Sindbis and Columbia SK viruses appeared similar when analyzed by zonal sedimentation in sucrose-sodium dodecyl sulfate.

Adenine Nucleotides↗
PubMed1972

Adenovirus messenger RNA in mammalian cells: failure of polyribosome association in the absence of nuclear cleavage.

The nuclear synthesis of adenovirus-specific RNA late in the infectious cycle in the presence of toyocamycin (an adenosine analogue) has been investigated. There is reduced synthesis of viral RNA with an accumulation of virus-specific RNA in the molecular weight range of at least 4 to 8 x 10(6). No new viral RNA associates with cytoplasmic polyribosomes. In addition, hybridization competition experiments indicate a 70% competition between these large nuclear transcripts and polyribosome-associated viral RNA that was synthesized in the absence of inhibitor. These data are consistent with the following interpretations: complete nuclear processing of viral RNA is necessary for polyribosome association, and precursor viral message(s) contain sequences that are lost normally during post-transcriptional processing.

Adenoviridae↗
PubMed1972

Purification and properties of biologically active messenger RNA for a myeloma light chain.

A cell-free system derived from Krebs II ascites tumor has been used to assay biologically active mRNA for myeloma (MOPC-41) light chain during its purification by oligothymidylate-cellulose chromatography and sucrose gradient centrifugation. The purified mRNA directs the synthesis of a product that yields tryptic peptides corresponding to those derived from authentic myeloma protein and that forms a specific immunoprecipitate with antibody directed against the MOPC-41 protein. The fact that the light-chain mRNA anneals to oligothymidylic acid-cellulose suggests that it, like several other eukaryotic mRNAs, contains a region rich in adenylic acid residues. The most active fractions of light-chain mRNA, representing about 0.1% of the RNA originally extracted from membrane-bound myeloma polysomes, sediment as a discrete peak with an s(20,w) of about 13, roughly corresponding to an RNA molecule containing 850 bases. The results suggest that the light-chain mRNA is monocistronic and that it contains about 200 more bases than would be necessary to encode the variable and constant regions of a single light-chain molecule.

Adenine Nucleotides↗
PubMed1972

Translation of messenger RNA for histones from HeLa cells by a cell-free extract from mouse ascites tumor.

7-9S RNA has been isolated from polyribosomes of HeLa S-3 cells in S phase. These RNA species direct the synthesis in vitro of all five classes of human histones when they are added to a protein-synthesizing system derived from mouse ascites tumor cells. The histones synthesized in vitro have been identified by two kinds of acrylamide gel electrophoresis, and by paper electrophoresis of tryptic digests. By use of the ratio of tyrosine to tryptophan incorporation as an index of contamination, it was determined that less than 10% of the 7-9S RNA is translated into proteins other than histones.

Amino Acids↗
PubMed1972

Estrogen-induced changes in translation, and specific messenger RNA levels during oviduct differentiation.

Estrogen-induced morphologic differentiation of chick oviduct is accompanied by increases in the total endogenous mRNA activity of oviduct polysomes. Concomitant increases are also noted in ribosome translational capacity and activity of peptide chain initiation factors. Once the differentiation process nears completion (about 7 days of estrogen administration), total ribosomebound mRNA activity decreases, but the translational machinery remains very active. In addition, estrogen induces the accumulation of ovalbumin mRNA before ovalbumin is demonstrable in the oviduct. The data suggest that the rate-limiting event in the hormonal induction of cell-specific proteins, such as ovalbumin, is the synthesis and intracellular accumulation of specific mRNA for such proteins.

Animals↗