Influenza virus NS1 protein is an RNA-binding whose expression alters several posttranscriptional regulatory processes, like polyadenylation, splicing, and nucleocytoplasmic transport of cellular mRNAs. In addition, enhances the translational rate viral, but not cellular, To characterize this effect, we looked for targets influenza among translation factors. We found that coimmunoprecipitates with eukaryotic initiation factor 4GI (eIF4GI), large subunit cap-binding complex eIF4F, either in...

Kinetic evidence of a time- and dose-dependent inactivation phosphofructokinase by glucagon in isolated rat hepatocytes is reported. This inactivation, which persists after gel filtration cell-free extract on Sephadex G-25 400-fold purification the enzyme agarose-ATP, observed when activity measured at subsaturating concentrations fructose 6-phosphate, while there no change Vmax. Phosphofructokinase parallels known pyruvate kinase L activation glycogen phosphorylase alpha. Exogenous cyclic...

Influenza A virus (IAV) infection can be severe or even lethal in toddlers, the elderly and patients with certain medical conditions. Infection of apparently healthy individuals nonetheless accounts for many disease cases deaths, suggesting that viruses increased pathogenicity co-circulate pandemic epidemic viruses. Looking potential virulence factors, we have identified a polymerase PA D529N mutation detected fatal IAV case, whose introduction into two different recombinant backbones, led...

It has previously been shown that influenza virus NS1 protein enhances the translation of viral but not cellular mRNAs. This enhancement occurs by increasing rate initiation and requires 5'UTR sequence, common to all In agreement with these findings, we show here mRNAs, are associated during infection. We have reported interacts factor eIF4GI, next its poly(A)-binding 1 (PABP1)-interacting domain eIF4GI in virus-infected cells. Here NS1, although capable binding poly(A), does compete PABP1...

The gene product of open reading frame 5 (p25) porcine reproductive and respiratory syndrome (PRRS) virus has been expressed by coinfection culture cells with vaccinia expressing the T7 RNA polymerase a recombinant encoding under promoter encephalomyocarditis internal ribosome entry site. In spite reported efficiency expression system, very poor accumulation p25 protein was observed strong cytotoxicity produced in doubly infected cells. This cell toxicity shown to occur induction apoptosis,...

It has been described that influenza virus polymerase associates with RNA II (RNAP II). To gain information about the role of this interaction, we explored if changes in RNAP occur during infection. Here show causes specific degradation hypophosphorylated form largest subunit without affecting accumulation its hyperphosphorylated forms. This effect is independent viral strain and origin cells used. Analysis synthesized mRNAs isolated nuclei infected indicated transcription decreases...

The PA subunit of the influenza virus polymerase complex is a phosphoprotein that induces proteolytic degradation coexpressed proteins. Point mutants with reduced proteolysis induction reconstitute viral ribonucleoproteins defective in replication but not transcriptional activity. To look for cellular factors could associate protein, we have carried out yeast two-hybrid screen. Using human kidney cDNA library, identified two different interacting clones. One them was as homologue previously...

The protein regions involved in the nuclear translocation of influenza virus PA polymerase subunit have been identified by deletion analysis expressed from a recombinant simian 40. Two seem to play role process: region I (amino acids 124 139) and II 186 247). A nucleoplasmin-like signal (NLS) has an additional NLS appears be present II, although no consensus targeting sequence can detected. Alteration any short deletions completely prevented transport, whereas elimination or large amino-...

Influenza A virus mutants expressing C-terminally deleted forms of the NS1 protein (NS1-81 and NS1-110) were generated by plasmid rescue. These viruses temperature sensitive showed a small plaque size at permissive temperature. The accumulation virion RNA in mutant virus-infected cells was reduced restrictive temperature, while cRNA or mRNA not affected, indicating that is involved control transcription versus replication processes infection. synthesis late proteins NS1-81 mutant-infected...

Glucagon produces a time- and dose-dependent activation of phospholipid methyltransferase activity in isolated rat hepatocytes. Half-maximal effect is caused by dose glucagon 1 x 10(-10) M. This due to an increase the Vmax value enzyme, without affecting Km for S-adenosylmethionine. Exogenous cyclic AMP added hepatocytes mimics glucagon, nonsaturating concentration spontaneously reversible within 40 min incubation.

Influenza virus mRNAs bear a short capped oligonucleotide sequence at their 5' ends derived from the host cell pre-mRNAs by "cap-snatching" mechanism, followed immediately common viral sequence. At 3' ends, they contain poly(A) tail. Although cellular and are structurally similar, influenza promotes selective translation of its despite inhibition protein synthesis. The polymerase performs cap snatching binds selectively to As recognized own cap-binding complex, we tested whether mRNA occurs...

hCLE/C14orf166 is a nuclear and cytoplasmic protein that interacts with the RNAP II, modulates RNA metabolism present in granules involved localized translation. Here we have studied whether hCLE shares common interactors nucleus cytosol, which could shed light on its participation sequential phases of metabolism. Nuclear purified hCLE-associated factors were identified proteins mRNA metabolism, motor-related proteins, cytoskeletal translation-related found. Purified complexes also contain...

Influenza epidemics affect all age groups, although children, the elderly and those with underlying medical conditions are most severely affected. Whereas co-morbidities present in 50% of fatal cases, 25-50% deaths apparently healthy individuals. This suggests genetic determinants that govern infection severity. Although some viral factors contribute to influenza disease known, role host remains undetermined. Data for small cohorts influenza-infected patients contradictory regarding...

Influenza virus stablishes a network of virus-host functional interactions, which depends on chromatin dynamic and therefore epigenetic modifications. Using an unbiased search, we analyzed the changes at DNA methylation post-translational histone modification levels induced by infection. was unaltered, while found general decrease acetylation, correlates with transcriptional inactivation may cooperate impairment cellular transcription that causes influenza A particular increase in H3K79...

Abstract Aims Human influenza A virus (hIAV) infection is associated with important cardiovascular complications, although cardiac pathophysiology poorly understood. We aimed to study the ability of hIAV different pathogenicity infect mouse heart, and establish relationship between infective capacity in vivo, cellular molecular alterations. Methods results evaluated lung heart viral titres mice infected either one several strains inoculated intranasally. 3D reconstructions tissue were used...

In the process of in vivo reconstitution influenza virus transcriptase-replicase complex, an inhibitory effect was observed when level PA protein expression increased. This inhibition paralleled by a decrease accumulation other core proteins. The sole sufficient to reduce proteins encoded coexpressed genes. upon and non-influenza independently system chosen origin cell line used. did not induce variations translation target but on their half-lives, which were clearly reduced. A functional...

We have previously described the fact that individual expression of influenza virus PA protein induced a generalized proteolysis (J.J. Sanz-Ezquerro, S. de la Luna, Ortin, and A. Nieto, J. Virol. 69:2420-2426, 1995). In this study, we further characterized effect by mapping regions required found deletion analysis first 247 amino acids are sufficient to bring about activity. mutants were able decrease accumulation levels coexpressed proteins also presented lower steady-state due reduction in...

ABSTRACT The PA subunit of the influenza virus polymerase complex is a phosphorylated protein that induces proteolytic process decreases its own accumulation levels and those coexpressed proteins. amino-terminal third responsible for induction proteolysis. We mutated five potential casein kinase II phosphorylation sites located in protein. Mutations affecting position 157 almost completely abrogated proteolysis induction, whereas mutation at 162 produced moderate decrease mutations positions...

Transcription and replication of influenza A virus are carried out in the nuclei infected cells context viral ribonucleoproteins (RNPs). The polymerase responsible for these processes is a protein complex composed PB1, PB2, PA proteins. We previously identified set polymerase-associated cellular proteins by proteomic analysis polymerase-containing intracellular complexes expressed purified from human cells. Here we characterize role NXP2/MORC3 infection cycle. member Microrchidia (MORC)...

Two panels of monoclonal antibodies (MAbs) specific for the influenza A virus PA and PB2 polypeptides have been obtained from mice immunized with denatured proteins produced in Escherichia coli. All MAbs (13 polypeptide 8 protein) reacted to corresponding protein Western blotting (immunoblotting), immunoprecipitation, immunofluorescence assays. To gain information about roles nucleoprotein (NP) during viral mRNA synthesis, 21 anti-P 3 anti-NP (J. A. López, M. Guillen, Sánchez-Fauquier, J....

Summary The influenza virus establishes close functional and structural connections with the nucleus of infected cell. Thus, viral ribonucleoproteins (RNPs) are closely bound to chromatin components main constituent RNPs, nucleoprotein (NP) protein, interacts histone tails. Using a yeast two-hybrid screening, we previously found that PA polymerase subunit CHD6 member CHD family remodelers. Here show also complex colocalizes RNPs in cells. To study relationships between CHD6, have analysed...

Upon viral infection, the production of type I interferon (IFN) and subsequent upregulation IFN stimulated genes (ISGs) generate an antiviral state with important role in activation innate adaptive host immune responses. The ubiquitin-like protein (UBL) ISG15 is a critical IFN-induced molecule that protects against several infections, but mechanism by which exerts its function not completely understood. Here, we report plays regulation macrophage ISG15−/− macrophages display reduced...

The influenza A virus polymerase associates with a number of cellular transcription-related factors, including RNA II. We previously described the interaction subunit PA human CLE/C14orf166 protein (hCLE), positive modulator this polymerase. Here, we show that hCLE also interacts complex and colocalizes viral ribonucleoproteins. Silencing causes reduction activity, transcription replication, titer, particle production. Altogether, these findings indicate factor is an important for replication.

ABSTRACT Influenza A virus requires ongoing cellular transcription to carry out the cap-snatching process. Chromatin remodelers modify chromatin structure produce an active or inactive conformation, which enables prevents recruitment of transcriptional complexes specific genes; viral thus depends on dynamics. polymerase associates with components infected cell, such as RNA II (RNAP II) CHD6 remodeler. Here we show that another CHD family member, CHD1 protein, also interacts influenza...