Search results for "S-"
showing 10 items of 16104 documents
Mouse models of cytomegalovirus latency: overview.
2002
Abstract Background: The molecular regulation of viral latency and reactivation is a central unsolved issue in the understanding of cytomegalovirus (CMV) biology. Like human CMV (hCMV), murine CMV (mCMV) can establish a latent infection in cells of the myeloid lineage. Since mCMV genome remains present in various organs after its clearance from hematopoietic cells first in bone marrow and much later in blood, there must exist one or more widely distributed cell type(s) representing the cellular site(s) of enduring mCMV latency in host tissues. Endothelial cells and histiocytes are candidates, but the question is not yet settled. Another long debated problem appears to be solved: mCMV establ…
Infection-induced chromatin modifications facilitate translocation of herpes simplex virus capsids to the inner nuclear membrane
2021
Herpes simplex virus capsids are assembled and packaged in the nucleus and move by diffusion through the nucleoplasm to the nuclear envelope for egress. Analyzing their motion provides conclusions not only on capsid transport but also on the properties of the nuclear environment during infection. We utilized live-cell imaging and single-particle tracking to characterize capsid motion relative to the host chromatin. The data indicate that as the chromatin was marginalized toward the nuclear envelope it presented a restrictive barrier to the capsids. However, later in infection this barrier became more permissive and the probability of capsids to enter the chromatin increased. Thus, although …
Nuclear localization but not PML protein is required for incorporation of the papillomavirus minor capsid protein L2 into virus-like particles.
2004
ABSTRACT Recent reports suggest that nuclear domain(s) 10 (ND10) is the site of papillomavirus morphogenesis. The viral genome replicates in or close to ND10. In addition, the minor capsid protein, L2, accumulates in these subnuclear structures and recruits the major capsid protein, L1. We have now used cell lines deficient for promyelocytic leukemia (PML) protein, the main structural component of ND10, to study the role of this nuclear protein for L2 incorporation into virus-like particles (VLPs). L2 expressed in PML protein knockout (PML −/− ) cells accumulated in nuclear dots, which resemble L2 aggregates forming at ND10 in PML protein-containing cells. These L2 assemblies also attracted…
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.
Impact of VP1-Specific Protein Sequence Motifs on Adeno-Associated Virus Type 2 Intracellular Trafficking and Nuclear Entry
2012
ABSTRACT Adeno-associated virus type 2 (AAV2) has gained much interest as a gene delivery vector. A hallmark of AAV2-mediated gene transfer is an intracellular conformational change of the virus capsid, leading to the exposure of infection-relevant protein domains. These protein domains, which are located on the N-terminal portion of the structural proteins VP1 and VP2, include a catalytic phospholipase A 2 domain and three clusters of basic amino acids. We have identified additional protein sequence motifs located on the VP1/2 N terminus that also proved to be obligatory for virus infectivity. These motifs include signals that are known to be involved in protein interaction, endosomal sort…
Immune responses during COVID-19 infection
2020
International audience; Over the past 16 years, three coronaviruses (CoVs), severe acute respiratory syndrome CoV (SARS-CoV) in 2002, Middle East respiratory syndrome CoV (MERS-CoV) in 2012 and 2015, and SARS-CoV-2 in 2020, have been causing severe and fatal human epidemics. The unpredictability of coronavirus disease-19 (COVID-19) poses a major burden on health care and economic systems across the world. This is caused by the paucity of in-depth knowledge of the risk factors for severe COVID-19, insufficient diagnostic tools for the detection of SARS-CoV-2, as well as the absence of specific and effective drug treatments. While protective humoral and cellular immune responses are usually m…
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…
STAT1 and Its Crucial Role in the Control of Viral Infections
2022
The signal transducer and activator of transcription (STAT) 1 protein plays a key role in the immune response against viruses and other pathogens by transducing, in the nucleus, the signal from type I, type II and type III IFNs. STAT1 activates the transcription of hundreds of genes, some of which have been well characterized for their antiviral properties. STAT1 gene deletion in mice and complete STAT1 deficiency in humans both cause rapid death from severe infections. STAT1 plays a key role in the immunoglobulin class-switch recombination through the upregulation of T-bet; it also plays a key role in the production of T-bet+ memory B cells that contribute to tissue-resident humoral memory…
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…
Signālu apstrādes metodes
2015
Maģistra darba mērķis ir aplūkot dažādas signālu apstrādes metodes, tās salīdzināt un pielietot praktiskām datu problēmām. Galvenā darba daļa ir veltīta Furjē teorijai un signālu filtrācijas metodēm, kā arī ar signālu apstrādi saistītām problēmām, tādām kā aliasings. Darbā tiek apskatīts filtrācijas metožu pielietojums skaņas signālu apstrādē. Galvenās filtrācijas metodes, kas aplūkotas darbā ir augstās/zemās caurlaides metode, joslas caurlaides metode, kā arī vispārīgā filtra metode un dekonvolūcijas metode. Tāpat darbā tiek aplūkota signālu salīdzināšana ar šķērs-korelācijas metodi un apskatīts šīs metodes praktisks pielietojums.