bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunogenicityof
Borrelia burgdorferi
Arthritis-RelatedProtein
Authors: Feng Sunlian , Hodzic Emir , Freet Kimberly , Barthold Stephen W. 
Published: November 2003

ABSTRACT

Immunization
against arthritis-related protein (Arp) elicits antibody in mice that
resolves arthritis but is not protective against challenge with
Borrelia burgdorferi
. In mice immunized against Arp, an
unrelated 37-kDa protein (P37-42), outer surface protein A (OspA), or
glutathione
S
-transferase (GT) and then challenged by syringe
or tick, only OspA conferred protection. Passive transfer of Arp
antiserum into infected SCID mice induced arthritis resolution, but
antisera to P37-42, OspA, GT, or six overlapping Arp peptide fragments
did not. Results suggest that the arthritis-resolving immunogenicity is
specific to Arp, but the relevant epitopes may be
conformational.
Abortive Potency ofChlamydophila abortusin Pregnant Mice Is Not Directly Correlated with Placental and Fetal Colonization Levels
Authors: Bouakane Amel , Benchaîeb Ilhem , Rodolakis Annie 
Published: November 2003

ABSTRACTAbortion, placental and fetal colonization, and levels of gamma interferon were analyzed for fourChlamydophila abortusstrains presenting antigenic variations in a mouse model. Expression of virulence of these strains varied and indicated that abortion was not directly related to the number of bacteria in the placenta, and thus, other factors may have an important role in activating the abortion process.
Mycobacterium aviumsubsp. paratuberculosisInfection Causes Suppression of RANTES, Monocyte Chemoattractant Protein 1, and Tumor Necrosis Factor Alpha Expression in Peripheral Blood of Experimentally Infected Cattle
Authors: Buza Joram J. , Mori Yasuyuki , Bari Abusaleh M. , Hikono Aodon-geril Hirokazu , Hirayama Sachiyo , Shu Yujing , Momotani Eiichi 
Published: November 2003

ABSTRACTBlood from cattle with subclinicalMycobacterium aviumsubsp.paratuberculosisinfection was stimulated withM. aviumsubsp.paratuberculosisantigens, and expression of interleukin-1β (IL-1β), tumor necrosis factor alpha (TNF-α), RANTES, monocyte chemoattractant protein 1 (MCP-1), and IL-8 was measured. Expression of TNF-α, RANTES, and MCP-1 was lower in infected than in uninfected cattle. The reduced response may weaken protective immunity and perpetuate infection.
Enhanced Phagocytosis ofCandidaSpecies Mediated by Opsonization with a Recombinant Human Antibody Single-Chain Variable Fragment
Authors: Wellington Melanie , Bliss Joseph M. , Haidaris Constantine G. 
Published: November 2003

ABSTRACTSpecific antibody opsonization significantly enhances the level of phagocytosis ofCandidain the absence of complement. Furthermore, we have described a system using a recombinant human antibody single-chain variable fragment that allows a comparative study of phagocytosis of multipleCandidaspecies opsonized via a common antigen.
Stability and Morphology Comparisons of Self-AssembledVirus-Like Particles from Wild-Type and Mutant Human Hepatitis B VirusCapsidProteins
Authors: Newman Margaret , Suk Fat-Moon , Cajimat Maria , Chua Pong Kian , Shih Chiaho 
Published: November 2003

ABSTRACT
Instead
of displaying the wild-type selective export of virions containing
mature genomes, human hepatitis B virus (HBV) mutant I97L, changing
from an isoleucine to a leucine at amino acid 97 of HBV core antigen
(HBcAg), lost the high stringency of selectivity in genome maturity
during virion export. To understand the structural basis of this
so-called “immature secretion” phenomenon, we compared
the stability and morphology of self-assembled capsid particles from
the wild-type and mutant I97L HBV, in either full-length (HBcAg1-183)
or truncated core protein contexts (HBcAg1-149 and HBcAg1-140). Using
negative staining and electron microscopy, full-length particles appear
as “thick-walled” spherical particles with little
interior space, whereas truncated particles appear as“
thin-walled” spherical particles with a much larger
inner space. We found no significant differences in capsid stability
between wild-type and mutant I97L particles under denaturing pH and
temperature in either full-length or truncated core protein contexts.
In general, HBV capsid particles (HBcAg1-183, HBcAg1-149, and
HBcAg1-140) are very robust but will dissociate at pH 2 or 14, at
temperatures higher than 75°C, or in 0.1% sodium dodecyl
sulfate (SDS). An unexpected upshift banding pattern of the SDS-treated
full-length particles during agarose gel electrophoresis is most likely
caused by disulfide bonding of the last cysteine of HBcAg. HBV capsids
are known to exist in natural infection as dimorphic T=3 or
T=4 icosahedral particles. No difference in the ratio between
T=3 (78%) and T=4 particles (20.3%) are
found between wild-type HBV and mutant I97L in the context of
HBcAg1-140. In addition, we found no difference in capsid stability
between T=3 and T=4 particles successfully separated by
using a novel agarose gel electrophoresis
procedure.
Intra- and Intermolecular Disulfide Bonds of theGP2bGlycoprotein of Equine Arteritis Virus: Relevance forVirus Assembly andInfectivity
Authors: Wieringa Roeland , de Vries Antoine A. F. , Post Sabine M. , Rottier Peter J. M. 
Published: November 2003

ABSTRACTEquine arteritis virus(EAV) is an enveloped, positive-strand RNA virus belonging to the familyArteriviridaeof the orderNidovirales. EAV virions contain six different envelope proteins. The glycoprotein GP5(previously named GL) and the unglycosylated membrane protein M are the major envelope proteins, while the glycoproteins GP2b(previously named GS), GP3, and GP4are minor structural proteins. The unglycosylated small hydrophobic envelope protein E is present in virus particles in intermediate molar amounts compared to the other transmembrane proteins. The GP5and M proteins are both essential for particle assembly. They occur as covalently linked heterodimers that constitute the basic protein matrix of the envelope. The GP2b, GP3, and GP4proteins occur as a heterotrimeric complex in which disulfide bonds play an important role. The function of this complex has not been established yet, but the available data suggest it to be involved in the viral entry process. Here we investigated the role of the four cysteine residues of the mature GP2bprotein in the assembly of the GP2b/GP3/GP4complex. Open reading frames encoding cysteine-to-serine mutants of the GP2bprotein were expressed independently or from a full-length infectious EAV cDNA clone. The results of these experiments support a model in which the cysteine residue at position 102 of GP2bforms an intermolecular cystine bridge with one of the cysteines of the GP4protein, while the cysteine residues at positions 48 and 137 of GP2bare linked by an intrachain disulfide bond. In this model, another cysteine residue in the GP4protein is responsible for the covalent association of GP3with the disulfide-linked GP2b/GP4heterodimer. In addition, our data highlight the importance of the correct association of the minor EAV envelope glycoproteins for their efficient incorporation into viral particles and for virus infectivity.
Reduction of Natural Adenovirus Tropism to Mouse Liverby Fiber-Shaft Exchange in Combination with both CAR- andαv Integrin-BindingAblation
Authors: Koizumi Naoya , Mizuguchi Hiroyuki , Sakurai Fuminori , Yamaguchi Teruhide , Watanabe Yoshiteru , Hayakawa Takao 
Published: November 2003

ABSTRACT
The
primary receptor, the coxsackievirus and adenovirus
receptor (CAR), and the secondary receptor, αv
integrins, are the tropism determinants of adenovirus (Ad) type 5.
Inhibition of the interaction of both the fiber with CAR and the penton
base with the αv integrin appears to be crucial to the
development of targeted Ad vectors, which specifically transduce a
given cell population. In this study, we developed Ad vectors with
ablation of both CAR and αv integrin binding by
mutating the fiber knob and the RGD motif of the penton base. We also
replaced the fiber shaft domain with that derived from Ad type 35. High
transduction efficiency in the mouse liver was suppressed approximately
130- to 270-fold by intravenous administration of the double-mutant Ad
vectors, which mutated two domains each of the fiber knob and shaft and
the RGD motif of the penton base compared with those of conventional Ad
vectors (type 5). Most significantly, the triple-mutant Ad vector
containing the fiber knob with ablation of CAR binding ability, the
fiber shaft of Ad type 35, and the penton base with a deletion of the
RGD motif mediated a >30,000-fold lower level of mouse liver
transduction than the conventional Ad vectors. This triple-mutant Ad
vector also mediated reduced transduction in other organs (the spleen,
kidney, heart, and lung). Viral DNA analysis showed that systemically
delivered triple-mutant Ad vector was primarily taken up by liver
nonparenchymal cells and that most viral DNAs were easily degraded,
resulting in little gene expression in the liver. These results suggest
that the fiber knob, fiber shaft, and RGD motif of the penton base each
plays an important role in Ad vector-mediated transduction to the mouse
liver and that the triple-mutant Ad vector exhibits little tropism to
any organs and appears to be a fundamental vector for targeted Ad
vectors.
Barrier-to-Autointegration Factor BAF Binds p55 Gagand Matrix and Is a Host Component of Human ImmunodeficiencyVirus Type 1Virions
Authors: Mansharamani Malini , Graham David R. M. , Monie Daphne , Lee Kenneth K. , Hildreth James E. K. , Siliciano Robert F. , Wilson Katherine L. 
Published: November 2003

ABSTRACT

Barrier-to-autointegration
factor (BAF) is a conserved human chromatin protein exploited by
retroviruses. Previous investigators showed that BAF binds
double-stranded DNA nonspecifically and is a host component of
preintegration complexes (PICs) isolated from cells infected with human
immunodeficiency virus type 1 (HIV-1) or Moloney murine leukemia virus.
BAF protects PIC structure and stimulates the integration of
salt-stripped PICs into target DNA in vitro. PICs are thought to
acquire BAF from the cytoplasm during infection. However, we identified
two human tissues (of 16 tested) in which BAF mRNA was not detected:
thymus and peripheral blood leukocytes, which are enriched in
CD4
+
T lymphocytes and macrophage precursors,
respectively. BAF protein was detected in activated but not resting
CD4
+
T lymphocytes; thus, if BAF were essential for
PIC function, we hypothesized that virions might “bring their
own BAF.” Supporting this model, BAF copurified with HIV-1
virions that were digested with subtilisin to remove microvesicle
contaminants, and BAF was present in approximately zero to three copies
per virion. In three independent assays, BAF bound directly to both p55
Gag (the structural precursor of HIV-1 virions) and its cleaved
product, matrix. Using lysates from cells overexpressing Gag,
endogenous BAF and Gag were coimmunoprecipitated by antibodies against
Gag. Purified recombinant BAF had low micromolar affinities (1.1 to 1.4μ
M) for recombinant Gag and matrix. We conclude that BAF is
present at low levels in incoming virions, in addition to being
acquired from the cytoplasm of newly infected cells. We further
conclude that BAF might contribute to the assembly or activity of HIV-1
PICs through direct binding to matrix, as well as
DNA.
An InternalRibosome Entry Site Directs Translation of the Murine Gammaherpesvirus68 MK3 Open ReadingFrame
Authors: Coleman Heather M. , Brierley Ian , Stevenson Philip G. 
Published: November 2003

ABSTRACT

The
gammaherpesviruses characteristically drive the proliferation of
latently infected lymphocytes. The murine gammaherpesvirus 68 (MHV-68)
MK3 protein contributes to this process in vivo by evading
CD8
+
-T-cell recognition during latency, as well as
during lytic infection. We analyzed some of the molecular mechanisms
that control MK3 expression. No dedicated MK3 mRNA was detected.
Instead, the MK3 open reading frame (ORF) was transcribed as part of a
bicistronic mRNA, downstream of a previously unidentified ORF, 13M. The
13M/MK3 promoter appeared to extend approximately 1 kb 5′ of
the transcription start site and included elements both dependent on
and independent of the ORF50 lytic transactivator. MK3 was translated
from the bicistronic transcript by virtue of an internal ribosome entry
site (IRES) element. RNA structure mapping identified two stem-loops
between 13M and MK3 that were sufficient for IRES activity in a
bicistronic reporter plasmid and a third stem-loop just within the MK3
coding sequence, with a subtler, perhaps regulatory role. Overall,
translation of the MHV-68 MK3 bore a striking resemblance to that of
the Kaposi's sarcoma-associated herpesvirus vFLIP, suggesting that
IRES elements are a common theme of latent gammaherpesvirus immune
evasion in proliferating
cells.
Chromosomal Integration and Homologous Gene Targetingby Replication-Incompetent Vectors Based on the Autonomous ParvovirusMinute Virus ofMice
Authors: Hendrie Paul C. , Hirata Roli K. , Russell David W. 
Published: November 2003

ABSTRACT

The
molecular mechanisms responsible for random integration and gene
targeting by recombinant adeno-associated virus (AAV) vectors are
largely unknown, and whether vectors derived from autonomous
parvoviruses transduce cells by similar pathways has not been
investigated. In this report, we constructed vectors based on the
autonomous parvovirus minute virus of mice (MVM) that were designed to
introduce a neomycin resistance expression cassette (
neo
) into
the X-linked human hypoxanthine phosphoribosyl transferase
(
HPRT
) locus. High-titer, replication-incompetent MVM vector
stocks were generated with a two-plasmid transfection system that
preserved the wild-type characteristic of packaging only one DNA
strand. Vectors with inserts in the forward or reverse orientations
packaged noncoding or coding strands, respectively. In human HT-1080
cells, MVM vector random integration frequencies
(

neo
+

colonies) were comparable to those
obtained with AAV vectors, and no difference was observed for noncoding
and coding strands.
HPRT
gene-targeting frequencies
(
HPRT
mutant colonies) were lower with MVM
vectors, and the noncoding strand frequency was threefold greater than
that of the coding strand. Random integration and gene-targeting events
were confirmed by Southern blot analysis of G418- and 6-thioguanine
(6TG)-resistant clones. In separate experiments, correction of an
alkaline phosphatase (AP) gene by gene targeting was nine times more
effective with a coding strand vector. The data suggest that
single-stranded parvoviral vector genomes are substrates for gene
targeting and possibly for random integration as
well.
Protection against Murine Leukemia Virus-InducedSpongiform Myeloencephalopathy in Mice Overexpressing Bcl-2 butNot in Mice Deficient for Interleukin-6, Inducible NitricOxide Synthetase, ICE, Fas, Fas Ligand, or TNF-R1Genes
Authors: Jolicoeur Paul , Hu Chunyan , Mak Tak W. , Martinou Jean-Claude , Kay Denis G. 
Published: November 2003

ABSTRACTSome murine leukemia viruses (MuLVs), among them Cas-Br-E andts-1 MuLVs, are neurovirulent, inducing spongiform myeloencephalopathy and hind limb paralysis in susceptible mice. It has been shown that theenvgene of these viruses harbors the determinant of neurovirulence. It appears that neuronal loss occurs by an indirect mechanism, since the target motor neurons have not been found to be infected. However, the pathogenesis of the disease remains unclear. Several lymphokines, cytokines, and other cellular effectors have been found to be aberrantly expressed in the brains of infected mice, but whether these are required for the development of the neurodegenerative lesions is not known. In an effort to identify the specific effectors which are indeed required for the initiation and/or development of spongiform myeloencephalopathy, we inoculated gene-deficient (knockout [KO]) mice withts-1 MuLV. We show here that interleukin-6 (IL-6), inducible nitric oxide synthetase (iNOS), ICE, Fas, Fas ligand (FasL), and TNF-R1 KO mice still develop signs of disease. However, transgenic mice overexpressing Bcl-2 in neurons (NSE/Bcl-2) were largely protected from hind limb paralysis and had less-severe spongiform lesions. These results indicate that motor neuron death occurs in this disease at least in part by a Bcl-2-inhibitable pathway not requiring the ICE, iNOS, Fas/FasL, TNF-R1, and IL-6 gene products.
Three-Dimensional Structures of the A, B, and CCapsids of Rhesus Monkey Rhadinovirus: Insights into GammaherpesvirusCapsid Assembly, Maturation, and DNAPackaging
Authors: Yu Xue-Kui , O'Connor Christine M. , Atanasov Ivo , Damania Blossom , Kedes Dean H. , Zhou Z. Hong 
Published: November 2003

ABSTRACT
Rhesus
monkey rhadinovirus (RRV) exhibits high levels of sequence homology to
human gammaherpesviruses, such as Kaposi's sarcoma-associated
herpesvirus, and grows to high titers in cell cultures, making it a
good model system for studying gammaherpesvirus capsid structure and
assembly. We have purified RRV A, B, and C capsids, thus for the first
time allowing direct structure comparisons by electron cryomicroscopy
and three-dimensional reconstruction. The results show that the shells
of these capsids are identical and are each composed of 12 pentons, 150
hexons, and 320 triplexes. Structural differences were apparent inside
the shells and through the penton channels. The A capsid is empty, and
its penton channels are open. The B capsid contains a scaffolding core,
and its penton channels are closed. The C capsid contains a DNA genome,
which is closely packaged into regularly spaced density shells (25Å
apart), and its penton channels are open. The different
statuses of the penton channels suggest a functional role of the
channels during capsid maturation, and the overall structural
similarities of RRV capsids to alphaherpesvirus capsids suggest a
common assembly and maturation pathway. The RRV A capsid reconstruction
at a 15-Å resolution, the best achieved for gammaherpesvirus
particles, reveals overall structural similarities to alpha- and
betaherpesvirus capsids. However, the outer regions of the capsid,
including densities attributed to the Ta triplex and the small
capsomer-interacting protein (SCIP or ORF65), exhibit prominent
differences from their structural counterparts in alphaherpesviruses.
This structural disparity suggests that SCIP and the triplex, together
with tegument and envelope proteins, confer structural and potentially
functional specificities to alpha-, beta-, and
gammaherpesviruses.
Mechanismof Action and Antiviral Activity of Benzimidazole-Based AllostericInhibitors of the Hepatitis C Virus RNA-Dependent RNAPolymerase
Authors: Tomei Licia , Altamura Sergio , Bartholomew Linda , Biroccio Antonino , Ceccacci Alessandra , Pacini Laura , Narjes Frank , Gennari Nadia , Bisbocci Monica , Incitti Ilario , Orsatti Laura , Harper Steven , Stansfield Ian , Rowley Michael , De Francesco Raffaele , Migliaccio Giovanni 
Published: November 2003

ABSTRACTThe RNA-dependent RNA polymerase of hepatitis C virus (HCV) is the catalytic subunit of the viral RNA amplification machinery and is an appealing target for the development of new therapeutic agents against HCV infection. Nonnucleoside inhibitors based on a benzimidazole scaffold have been recently reported. Compounds of this class are efficient inhibitors of HCV RNA replication in cell culture, thus providing attractive candidates for further development. Here we report the detailed analysis of the mechanism of action of selected benzimidazole inhibitors. Kinetic data and binding experiments indicated that these compounds act as allosteric inhibitors that block the activity of the polymerase prior to the elongation step. Escape mutations that confer resistance to these compounds map to proline 495, a residue located on the surface of the polymerase thumb domain and away from the active site. Substitution of this residue is sufficient to make the HCV enzyme and replicons resistant to the inhibitors. Interestingly, proline 495 lies in a recently identified noncatalytic GTP-binding site, thus validating it as a potential allosteric site that can be targeted by small-molecule inhibitors of HCV polymerase.
SignalsThat Dictate Nuclear Localization of Human Papillomavirus Type 16Oncoprotein E6 in LivingCells
Authors: Tao Mingfang , Kruhlak Michael , Xia Shuhua , Androphy Elliot , Zheng Zhi-Ming 
Published: November 2003

ABSTRACT
Human
papillomavirus (HPV) type 16 E6 (16E6) is an oncogenic, multifunctional
nuclear protein that induces p53 degradation and perturbs normal cell
cycle control, leading to immortalization and transformation of
infected keratinocytes and epithelial cells. Although it is unclear how
16E6 disrupts the epigenetic profile of host genes, its presence in the
nucleus is a key feature. The present report describes intrinsic
properties of 16E6 that influence its nuclear import in living cells.
When the coding region of full-length 16E6 was inserted in frame into
the C terminus of green fluorescent protein (GFP), it effectively
prevented the 16E6 pre-mRNA from being spliced and led to the
expression of a GFP-E6 fusion which localized predominantly
to the nucleus. Further studies identified three novel nuclear
localization signals (NLSs) in 16E6 that drive the protein to
accumulate in the nucleus. We found that all three NLS sequences are
rich in positively charged basic residues and that point mutations in
these key residues could abolish the retention of 16E6 in the nucleus
as well as the p53 degradation and cell immortalization activities of
the protein. When inserted into corresponding regions of low-risk HPV
type 6 E6, the three NLS sequences described for 16E6 functioned
actively in converting the normally cytoplasmic HPV type 6 E6 into a
nuclear protein. The separate NLS sequences, however, appear to play
different roles in nuclear import and retention of HPV E6. The
discovery of three unique NLS sequences in 16E6 provides new insights
into the nuclear association of 16E6 which may reveal other novel
activities of this important oncogenic
protein.
Association of Adenovirus with the MicrotubuleOrganizingCenter
Authors: Bailey Christopher J. , Crystal Ronald G. , Leopold Philip L. 
Published: November 2003

ABSTRACT
Adenoviruses
(Ad) must deliver their genomes to the nucleus of the target cell to
initiate an infection. Following entry into the cell and escape from
the endosome, Ad traffics along the microtubule cytoskeleton toward the
nucleus. In the final step in Ad trafficking, Ad must leave the
microtubule and establish an association with the nuclear envelope. We
hypothesized that in cells lacking a nucleus, the capsid moves to and
associates with the microtubule organizing center (MTOC). To test this
hypothesis, we established an experimental system to examine Ad
trafficking in enucleated cells compared to Ad trafficking in intact,
mock-enucleated cells. Enucleation of a monolayer of A549 human lung
epithelial cells was accomplished by depolymerization of the actin
cytoskeleton followed by centrifugation. Upon infection of enucleated
cells with Cy3-labeled Ad, the majority of Ad capsid trafficked to a
discrete, centrally located site which colocalized with pericentrin, a
component of the MTOC. MTOC-associated Ad had escaped from endosomes
and thus had direct access to MTOC components. Ad localization at this
site was sensitive to the microtubule-depolymerizing agent nocodazole,
but not to the microfilament-depolymerizing agent cytochalasin B,
indicating that intact microtubules were required to maintain the
localization with the MTOC. Ad localization to the MTOC in the
enucleated cells was stable, as demonstrated by continuing Ad
localization with pericentrin for more than 5 h after
infection, a strong preference for Ad arrival at rather than Ad
departure from the MTOC, and minimal redistribution of Ad between MTOCs
within a single cell. In summary, the data demonstrate that the Ad
capsid establishes a stable interaction with the MTOC when a nucleus is
not present, suggesting that dissociation of Ad from microtubules
likely requires nuclear
factors.