Search results for "Oso"

Viral and cellular determinants of hepatitis C virus RNA replication in cell culture.

2003

Studies on the replication of hepatitis C virus (HCV) have been facilitated by the development of selectable subgenomic replicons replicating in the human hepatoma cell line Huh-7 at a surprisingly high level. Analysis of the replicon population in selected cells revealed the occurrence of cell culture-adaptive mutations that enhance RNA replication substantially. To gain a better understanding of HCV cell culture adaptation, we characterized conserved mutations identified by sequence analysis of 26 independent replicon cell clones for their effect on RNA replication. Mutations enhancing replication were found in nearly every nonstructural (NS) protein, and they could be subdivided into at …

Human Papillomavirus Types 16, 18, and 31 Share Similar Endocytic Requirements for Entry

2013

ABSTRACT Human papillomavirus type 18 (HPV18), one of the HPVs with malignant potential, enters cells by an unknown endocytic mechanism. The key cellular requirements for HPV18 endocytosis were tested in comparison to those for HPV16 and -31 endocytoses. HPV18 (like HPV16 and -31) entry was independent of clathrin, caveolin, dynamin, and lipid rafts but required actin polymerization and tetraspanin CD151, and the viruses were routed to the same LAMP-1-positive compartment. Hence, the viruses shared similar cellular requirements for endocytic entry.

In vitro studies on the activation of the hepatitis C virus NS3 proteinase by the NS4A cofactor.

1996

AbstractProteolytic processing of the nonstructural proteins of the hepatitis C virus (HCV) is mediated by two viral proteinases: the NS2-3 proteinase cleaving at the NS2/3 junction and the NS3 serine-type proteinase responsible for processing at the NS3/4A, NS4A/B, NS4B/5A, and NS5A/B sites. Activity of the NS3 proteinase is modulated by NS4A. In the absence of this cofactor processing at the NS3-dependent sites does not occur or, in the case of the NS5A/B junction, is poor but increased when NS4A is present. Although recent studies demonstrated that proteinase activation requires direct interaction between NS3 and NS4A, the mechanism by which NS4A exerts the activation function is not kno…

Single amino acid substitutions in the glycoprotein B carboxy terminus influence the fusion from without property of herpes simplex virus type 1.

1995

Syncytial mutations of herpes simplex virus type 1 (HSV-1) strains ANG, ANG path, HFEM, tsB5 and HSZP cause extensive cell fusion and were mapped to the cytoplasmic domain of glycoprotein B (gB), within the syn 3 locus. These strains are so far the only ones which show the phenotype ‘fusion from without’ (FFWO): 60 min after infection with high m.o.i., cells in a tissue culture are fused without transcription and translation of the viral genome. In this report we detected, using the recombinants 27/III and K-7, that an amino acid exchange from Ala to Val at aa position 854 of gB is the main determinant for FFWO activity of strains ANG, ANG path and recombinant K-7. The transfer of this muta…

Molecular Basis of SARS-CoV-2 Nsp1-Induced Immune Translational Shutdown as Revealed by All-Atom Simulations.

2021

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic represents the most severe global health crisis in modern human history. One of the major SARS-CoV-2 virulence factors is nonstructural protein 1 (Nsp1), which, outcompeting with the binding of host mRNA to the human ribosome, triggers a translation shutdown of the host immune system. Here, microsecond-long all-atom simulations of the C-terminal portion of the SARS-CoV-2/SARS-CoV Nsp1 in complex with the 40S ribosome disclose that SARS-CoV-2 Nsp1 has evolved from its SARS-CoV ortholog to more effectively hijack the ribosome by undergoing a critical switch of Q/E158 and E/Q159 residues that perfects Nsp1's interactions…

SARS-CoV-2 envelope protein topology in eukaryotic membranes

2020

Coronavirus E protein is a small membrane protein found in the virus envelope. Different coronavirus E proteins share striking biochemical and functional similarities, but sequence conservation is limited. In this report, we studied the E protein topology from the new SARS-CoV-2 virus both in microsomal membranes and in mammalian cells. Experimental data reveal that E protein is a single-spanning membrane protein with the N-terminus being translocated across the membrane, while the C-terminus is exposed to the cytoplasmic side (Nt lum /Ct cyt ). The defined membrane protein topology of SARS-CoV-2 E protein may provide a useful framework to understand its interaction with other viral and ho…

First-order visual interneurons distribute distinct contrast and luminance information across ON and OFF pathways to achieve stable behavior

2022

Source data of the paper Ketkar, Gür, Molina-Obando et al. 2022, eLife. We analyzed the behavioral contribution and physiological response properties of first order interneurons L1, L2 and L3 in the Drosophila melanogaster visual system. Data are sorted by figures and comprise either behavioral measurements of flies walking on an air-cushioned ball while being shown visual stimuli, or in vivo two photon microscopy recordings of L1-L3 calcium responses. Please find all relevant information to use the data in the README file. The code to analyze the data, either written in Matlab or Python, is found at https://github.com/silieslab/Ketkar-Gur-MolinaObando-etal2022

(A,B) In vivo GCaMP6f signals recorded in layers M1, M5 and M9/10 of Mi1 (A) and Tm3 (B) neurons, before (blue, green) and after (gray, red) applicat…

2019

Sensory systems sequentially extract increasingly complex features. ON and OFF pathways, for example, encode increases or decreases of a stimulus from a common input. This ON/OFF pathway split is thought to occur at individual synaptic connections through a sign-inverting synapse in one of the pathways. Here, we show that ON selectivity is a multisynaptic process in the Drosophila visual system. A pharmacogenetics approach demonstrates that both glutamatergic inhibition through GluClα and GABAergic inhibition through Rdl mediate ON responses. Although neurons postsynaptic to the glutamatergic ON pathway input L1 lose all responses in GluClα mutants, they are resistant to a cell-type-specifi…

Glie et neurones : vers un partenariat actif influençant le comportement sensoriel chez la drosophile

2014

Alla ricerca dell'autosostenibilità. Visioni e scenari per territorio e comunità

2021

Riflettere e ritornare a ripensare le relazioni tra le varie arti e i vari campi del sapere scientifico è oggi quanto mai necessario vista la tendenza esplicita alla liquefazione, allo scollamento e alla dispersione tra e dei processi intellettuali (sempre più omologati sulla necessità di aver successo mediatico nel messaggio immediato e mediante slogan e packaging più che risolvere, concretamente, i fatti urbani e territoriali) e alla costante separazione con le tecniche, i metodi e le attività burocratiche (anche esse sempre più meccaniche e industriali che fanno spesso il paio con processi di economie di scala). Entrambi gli aspetti divengono sempre più seriali, globalizzati e standardiz…