Search results for " mRNA"
showing 10 items of 61 documents
Genetic Analysis of Sequences in the 3′ Nontranslated Region of Hepatitis C Virus That Are Important for RNA Replication
2002
ABSTRACT The genome of the hepatitis C virus (HCV) is a plus-strand RNA molecule that carries a single long open reading frame. It is flanked at either end by highly conserved nontranslated regions (NTRs) that mediate crucial steps in the viral life cycle. The 3′ NTR of HCV has a tripartite structure composed of an about 40-nucleotide variable region, a poly(U/UC) tract that has a heterogeneous length, and a highly conserved 98-nucleotide 3′-terminal sequence designated the X tail or 3′X. Conflicting data as to the role the sequences in the 3′ NTR play in RNA replication have been reported. By using the HCV replicon system, which is based on the self-replication of subgenomic HCV RNAs in hu…
Soot-exposed mononuclear cells increase inflammatory cytokine mRNA expression and protein secretion in cocultured bronchial epithelial cells.
2000
<i>Background:</i> Soot particles are air pollutants capable of inducing airway and lung parenchymal injury. Mononuclear and bronchial epithelial cells are central to the maintenance of homeostasis and inflammation in the airways. <i>Objectives:</i> The aim of this study was to evaluate the contribution of mononuclear cells to the release of inflammatory mediators by bronchial epithelial cells. <i>Methods:</i> To model the in vivo situation, an in vitro system of cocultured blood monocytes and BEAS-2B cells was established in a transwell system. Blood monocytes were exposed to soot particles (FR 101) at concentrations of up to 100 μg/10<sup>6</su…
ROLE OF RNA BINDING PROTEIN IN THE NERVE CELL DIFFERENTIATION
2014
Synthesis of H1˚ and H3.3 histone proteins, in the developing rat brain, seems to be regulated mainly at the post-transcriptional level. Since regulation of RNA metabolism depends on a series of RNA-binding proteins (RBPs), we have been searching for RBPs involved in the post-transcriptional regulation of the H1˚ and H3.3 genes. Previously, we reported isolation, from a cDNA expression library, of an insert encoding a novel protein, the C-terminal half of which is identical to that of PEP-19, a brain-specific protein involved in calcium metabolism. The novel protein was called long PEP-19 isoform (LPI). We showed that LPI, as well as PEP-19, can bind H1˚ RNA. Since PEP19 and LPI contain a c…
The total mRNA concentration buffering system in yeast is global rather than gene-specific
2021
Gene expression in eukaryotes does not follow a linear process from transcription to translation and mRNA degradation. Instead it follows a circular process in which cytoplasmic mRNA decay crosstalks with nuclear transcription. In many instances, this crosstalk contributes to buffer mRNA at a roughly constant concentration. Whether the mRNA buffering concept operates on the total mRNA concentration or at the gene-specific level, and if the mechanism to do so is a global or a specific one, remain unknown. Here we assessed changes in mRNA concentrations and their synthesis rates along the transcriptome of aneuploid strains of the yeast Saccharomyces cerevisiae. We also assessed mRNA concentra…
Cancer cells can affect behaviour of neighbouring cells by transferring molecules through extracellular vesicles
2017
Most cells release into the extracellular space membrane-bound structures of different sizes, origin and composition, collectively called extracellular vesicles (EVs) [1]. Tumor cells are much more active than normal cells in producing EVs. Because of this property, they are able to transfer both nucleic acids and proteins to the surrounding normal cells, thus inducing in these latter at least some transformed behavior. We previously showed that EVs produced by G26/24 oligodendroglioma cells can horizontally transfer to their neighbours radioactive proteins [2]. In addition, EVs released by these cells contain pro-apoptotic proteins, such as TRAIL and Fas-Ligand, able to induce apoptosis in…
RNA as a carrier of epigenetic information
2017
Both prokaryotic and eukaryotic cells release into the extracellular matrix membrane-bound structures of different sizes, origin and composition, collectively called extracellular vesicles (EVs) [1]. Tumor cells, in particular, use EVs to transfer both nucleic acids and proteins to the surrounding normal cells, thus inducing in them transformed behaviours or killing them. G26/24 oligodendroglioma cells, for example, transfer by EVs pro-apoptotic proteins, such as TRAIL and Fas-Ligand [2], extracellular matrix remodelling proteases (such as ADAMTS) [3], and even the H1.0 histone protein [4]. Another tumour cell line, with a different tissue origin (A375 melanoma cells) releases into the medi…
Identification of a prognostic gene signature associated with MBP-1 expression in ErbB2-negative breast carcinomas
2014
The ENO1 transcript, which encodes the glycolitic enzyme alpha-enolase, can be translated into a shorter nuclear protein called Myc-promoter Binding Protein-1 (MBP-1) by using an alternative translation start site. MBP-1 acts as a negative regulator of c-Myc, ErbB2 and Cox2 genes (1). Several evidences indicate that MBP-1 acts as a tumor suppressor in breast carcinoma and prostate cancer and its expression results in a reduced invasive ability (2). In our previous studies, we showed that MBP-1 is expressed and easily detectable in normal breast epithelial cells, but a loss of expression occurs in most primary invasive ductal carcinomas (IDC) of the breast. Furthermore, in these tumors MBP-1…
RNA quality control: RppH activity allows selective removal of nonsense messages in E. coli.
2009
Polar effect, the reduced expression level of sequences downstream to mutations reducing translation efficiency, is usually due to transcription termination or inefficient translation reinitiation. Untranslated mRNAs are known to be quickly degraded, probably because of their increased accessibility to degradative enzymes due to the absence of translating ribosomes. In III-VI-I operon of phage f1, a strong polar effect is observed in a gIII 5’ proximal nonsense mutant, resulting in a very fast, RNaseE mediated, degradation of any full-length mRNA. RNaseE is a key component of the E. coli degradosome, the major RNA processing/degrading machinery. Its endonucleolytic activity is strongly enha…
Specific binding of VegT mRNA localization signal to membranes in Xenopus oocytes
2021
Abstract We have studied the interaction of a VegT mRNA localization signal sequence with the membranes of the mitochondrial cloud in Xenopus oocytes, and the binding of the VegT mRNA signal sequence to the lipid raft regions of the vesicles bounded by ordered and disordered phospholipid bilayers. RNA preference for the membranes of the mitochondrial cloud was confirmed using microscopy of a fluorescence resonance energy transfer from RNA molecules to membranes. Our studies show that VegT mRNA has a higher affinity for ordered regions of lipid bilayers. This conclusion is supported by the dissociation constant measurements for RNA-liposome complex and the visualization of the FRET signal be…
Aberrant splicing of the Drosophila melanogaster phenylalanine hydroxylase pre-mRNA caused by the insertion of a B104/roo transposable element in the…
1999
Abstract We report the insertion of the transposable element B104 in the Phenylalanine hydroxylase gene of the Drosophila mutant Henna-recessive 3 . Its presence alters the Phenylalanine hydroxylase splicing pattern, producing at least two aberrant mRNAs which contain part of the B104 sequence interrupting the coding region. This aberrant splicing is provoked by the use of a cryptic donor site encoded by the B104 3′ long terminal repeat in combination with either the gene intron 3 acceptor site or a novel acceptor site generated by the target duplication caused by transposition. One of them, referred as mRNA type 1, encodes a truncated protein that could be predictably non-functional. In mR…