Search results for "DNA"
showing 10 items of 6803 documents
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 …
DNA-induced structural changes in the papillomavirus capsid.
2001
ABSTRACT Human papillomavirus capsid assembly requires intercapsomeric disulfide bonds between molecules of the major capsid protein L1. Virions isolated from naturally occurring lesions have a higher degree of cross-linking than virus-like particles (VLPs), which have been generated in eukaryotic expression systems. Here we show that DNA encapsidation into VLPs leads to increased cross-linking between L1 molecules comparable to that seen in virions. A higher trypsin resistance, indicating a tighter association of capsomeres through DNA interaction, accompanies this structural change.
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…
Molecular Characterization of a Variant of Bacillus anthracis-Specific Phage AP50 with Improved Bacteriolytic Activity▿ †
2008
ABSTRACT The genome sequence of a Bacillus anthracis -specific clear plaque mutant phage, AP50c, contains 31 open reading frames spanning 14,398 bp, has two mutations compared to wild-type AP50t, and has a colinear genome architecture highly similar to that of gram-positive Tectiviridae phages. Spontaneous AP50c-resistant B. anthracis mutants exhibit a mucoid colony phenotype.
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…
Colonization of adrenal glands and ovaries of mice by variants of HSV 1 and 2
1991
The herpes simplex virus (HSV)-infected mouse model was used to correlate histopathological lesions in adrenal glands and ovaries with the localisation of viral nucleic acids and viral antigens, employing in situ hybridization and immunohistochemistry. In the adrenals, the lesions were mainly restricted to the zona fasciculata and the zona reticularis, sometimes extending to the medulla. In the ovaries, lesions were detected in follicles and in the stroma. During the course of infection, HSV nucleic acids could be detected earlier than HSV proteins. Next to the center of necrotic foci mainly HSV proteins were detected, whereas peripheral cells were found to contain viral nucleic acids. In s…
Pseudovirions as Specific Tools for Investigation of Virus Interactions With Cells
2004
This chapter outlines the generation and application of human papillomavirus type 33 (HPV33) pseudovirions. The method describes (1) the construction of vaccinia viruses recombinant for the major and minor HPV capsid proteins, L1 and L2, respectively; (2) the transfection of Cos7 cells with a marker plasmid replicating to high copy numbers; (3) the expression of L1 and L2 using the vaccinia virus expression system; (4) the extraction, purification, and analysis of HPV33 pseudovirions; and (5) their use in pseudoinfection assays. These pseudovirions are structurally indistinguishable from native virions and are therefore valuable tools for the study of papillomavirus-cell interactions. The m…
Characterization of the autoantigen La (SS-B) as a dsRNA unwinding enzyme
1997
During the analysis of the La (SS-B) autoantigen for catalytic activities an ATP-dependent double-stranded RNA unwinding activity was detected. Both native and recombinant La proteins from different species displayed this activity, which could be inhibited by monospecific anti-La antibodies. La protein was able to melt dsRNA substrates with either two 3'-overhangs or a single 3'- and a 5'-overhang. Double-stranded RNAs with two 5'-overhangs were not unwound, indicating that at least one 3'-overhang is required for unwinding. Sequence elements of the La protein that might be involved in dsRNA unwinding, such as an evolutionarily conserved putative ATP-binding motif and an element that is hom…
Modele eklezjalnej jedności chrześcijan
2018
Dla rozwoju ruchu ekumenicznego potrzeba modeli określających możliwości jednoczenia się chrześcijan. Dialogi ekumeniczne pokazują, że w prawie każdym Kościele chrześcijańskim wyobrażenia o jedności są różne. Z problemem braku jednej wizji jedności łączy się drugi – brak jednego pojęcia Kościoła, a przynajmniej brak takiego jego rozumienia, które byłoby akceptowane przez wszystkich chrześcijan. Trzeci problem związany jest z dwoma poprzednimi i dotyczy ekumenicznej hermeneutyki, która jest uzależniona od różnych eklezjalnych modeli jedności. Wyznaniowe uwarunkowania sprawiają, że inną wizję jedności mają prawosławni, inną protestanci, a jeszcze inną katolicy. Artykuł prezentuje głównie w op…