bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intrarenal Abscesses Due to
Ureaplasma urealyticum
in a Transplanted Kidney
Authors: Eilers Elisabeth , Moter Annette , Bollmann Renate , Haffner Dieter , Querfeld Uwe 
Published: January 2007

ABSTRACT

A young woman developed multiple abscesses in her transplanted kidney. Amplification of the 16S rRNA gene with subsequent sequencing revealed
Ureaplasma urealyticum
as the infectious agent. Microbiological diagnosis and sensitivity testing led to therapy with levofloxacin, resulting in rapid recovery of the patient.
PCR Detection of
Entamoeba histolytica
,
Entamoeba dispar
, and
Entamoeba moshkovskii
in Stool Samples from Sydney, Australia
Authors: Fotedar R. , Stark D. , Beebe N. , Marriott D. , Ellis J. , Harkness J. 
Published: January 2007

ABSTRACT

This study investigated the presence of
Entamoeba histolytica
,
Entamoeba dispar
, and
Entamoeba moshkovskii
in stool samples from a patient population in Sydney, Australia. Stool samples were tested by microscopy and PCR. Five patients were found with
E. histolytica
infections, while
E. dispar
and
E. moshkovskii
were observed in 63 (70.8%) and 55 (61.8%) patients, respectively, by PCR. This is the first study in Australia using molecular techniques to determine the presence of
E. histolytica
,
E. dispar
, and
E. moshkovskii
.
Monitoring of Hepatitis C Virus Quasispecies in Chronic Infection by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Mutation Detection
Authors: Yea Carmen , Bukh Jens , Ayers Melissa , Roberts Eve , Krajden Mel , Tellier Raymond 
Published: January 2007

ABSTRACT
Using both a mass spectrometry-based method and the classical method of cloning and sequencing, we demonstrated weekly changes in the hypervariable region 1 quasispecies of a chimpanzee infected with an infectious clone, coinciding with neutralizing antibody emergence. We also used the mass spectrometry method in the clinical follow-up of a chronically infected patient over a 5-year period.
An RNA-Binding Protein, hnRNP A1, and a Scaffold Protein, Septin 6, Facilitate Hepatitis C Virus Replication
Authors: Kim Chon Saeng , Seol Su Kyoung , Song Ok-Kyu , Park Ji Hoon , Jang Sung Key 
Published: January 2007

ABSTRACT

Hepatitis C virus (HCV) is a positive-sense single-stranded RNA virus. NS5b is an RNA-dependent RNA polymerase that polymerizes the newly synthesized RNA. HCV likely uses host proteins for its replication, similar to other RNA viruses. To identify the cellular factors involved in HCV replication, we searched for cellular proteins that interact with the NS5b protein. HnRNP A1 and septin 6 proteins were identified by coimmunoprecipitation and yeast two-hybrid screening, respectively. Interestingly, septin 6 protein also interacts with hnRNP A1. Moreover, hnRNP A1 interacts with the 5′-nontranslated region (5′ NTR) and the 3′ NTR of HCV RNA containing the
cis
-acting elements required for replication. Knockdown of hnRNP A1 and overexpression of C-terminally truncated hnRNP A1 reduced HCV replication. In addition, knockdown of septin 6 and overexpression of N-terminally truncated septin 6 inhibited HCV replication. These results indicate that the host proteins hnRNP A1 and septin 6 play important roles in the replication of HCV through RNA-protein and protein-protein interactions.
Correct Capsid Assembly Mediated by a Conserved YXXLGL Motif in Prototype Foamy Virus Gag Is Essential for Infectivity and Reverse Transcription of the Viral Genome
Authors: Mannigel Ingrid , Stange Annett , Zentgraf Hanswalter , Lindemann Dirk 
Published: January 2007

ABSTRACT

Unlike
other retrovirus Gag proteins, the prototype foamy virus (PFV)
p71

g

ag

protein is not processed
into mature matrix (MA), capsid (CA), and nucleocapsid (NC) subunits.
Little information about sequence motifs involved in FV capsid assembly
and release is available. The recent analysis of candidate L-domain
motifs in PFV Gag identified an evolutionarily conserved YXXL sequence
motif with a potential function in capsid assembly. Here we provide
support for the hypothesis that this motif does not function like a
conventional L domain, by demonstrating that, unlike the PFV Gag
PSAP L-domain motif, it cannot be functionally replaced by
heterologous L-domain sequences. Furthermore, mutation of individual
amino acids Y
464
, I
466
, L
467
, and
L
469
, but not E
465
, to alanine led to reduced
particle release and production of noninfectious, aberrant capsid
structures, although relative structural protein incorporation and
processing were not affected. In contrast, mutation of G
468
to alanine resulted in an intermediate, temperature-sensitive phenotype
characterized by reduced particle release and reduced infectivity.
Despite similar relative RNA genome incorporation for all mutants,
analysis and quantification of particle-associated viral nucleic acids
demonstrated defects in genomic reverse transcription for all the
noninfectious mutants, a process that, unlike that of
orthoretroviruses, in the case of FVs takes place in the
virus-producing cell. In correlation with the reduced infectivity, the
G
468
A mutant displayed an intermediate level of genomic
reverse transcription. Taken together, these results demonstrate that
the conserved YXXLGL motif in PFV Gag is involved in correct capsid
assembly, which in turn is essential for reverse transcription of the
FV
genome.
Cytoplasmic Localization of the ORF2 Protein of Hepatitis E Virus Is Dependent on Its Ability To Undergo Retrotranslocation from the Endoplasmic Reticulum
Authors: Surjit Milan , Jameel Shahid , Lal Sunil K. 
Published: January 2007

ABSTRACT
Hepatitis E virus (HEV) is a positive-strand RNA virus that is prevalent in much of the developing world. ORF2 is the major capsid protein of HEV. Although ORF2 is an N-linked glycoprotein, it is abundantly located in the cytoplasm in addition to having membrane and surface localization. The mechanism by which ORF2 protein obtains access to the cytoplasm is unknown. In this report, we prove that initially all ORF2 protein is present in the endoplasmic reticulum and a fraction of it becomes retrotranslocated to the cytoplasm. The ability of ORF2 to be retrotranslocated is dependent on its glycosylation status and follows the canonical dislocation pathway. However, in contrast to general substrates of the dislocation pathway, retrotranslocated ORF2 protein is not a substrate of the 26S proteasome complex and is readily detectable in the cytoplasm in the absence of any protease inhibitor, suggesting that the retrotranslocated protein is stable in the cytoplasm. This study thus defines the pathway by which ORF2 obtains access to the cytoplasm.
Formation of a Multiple Protein Complex on the Adenovirus Packaging Sequence by the IVa2 Protein
Authors: Tyler Ryan E. , Ewing Sean G. , Imperiale Michael J. 
Published: January 2007

ABSTRACT

During adenovirus virion assembly, the packaging sequence mediates the encapsidation of the viral genome. This sequence is composed of seven functional units, termed A repeats. Recent evidence suggests that the adenovirus IVa2 protein binds the packaging sequence and is involved in packaging of the genome. Study of the IVa2-packaging sequence interaction has been hindered by difficulty in purifying the protein produced in virus-infected cells or by recombinant techniques. We report the first purification of a recombinant untagged version of the adenovirus IVa2 protein and characterize its binding to the packaging sequence in vitro. Our data indicate that there is more than one IVa2 binding site within the packaging sequence and that IVa2 binding to DNA requires the A-repeat consensus, 5′-TTTG-(N
8
)-CG-3′. Furthermore, we present evidence that IVa2 forms a multimeric complex on the packaging sequence. These data support a model in which adenovirus DNA packaging occurs via the formation of a IVa2 multiprotein complex on the packaging sequence.
Mapping of the VP40-Binding Regions of the Nucleoprotein of Ebola Virus
Authors: Noda Takeshi , Watanabe Shinji , Sagara Hiroshi , Kawaoka Yoshihiro 
Published: January 2007

ABSTRACT
Expression of Ebola virus nucleoprotein (NP) in mammalian cells leads to the formation of helical structures, which serve as a scaffold for the nucleocapsid. We recently found that NP binding with the matrix protein VP40 is important for nucleocapsid incorporation into virions (T. Noda, H. Ebihara, Y. Muramoto, K. Fujii, A. Takada, H. Sagara, J. H. Kim, H. Kida, H. Feldmann, and Y. Kawaoka, PLoS Pathog. 2:e99, 2006). To identify the region(s) on the NP molecule required for VP40 binding, we examined the interaction of a series of NP deletion mutants with VP40 biochemically and ultrastructurally. We found that both termini of NP (amino acids 2 to 150 and 601 to 739) are essential for its interaction with VP40 and for its incorporation into virus-like particles (VLPs). We also found that the C terminus of NP is important for nucleocapsid incorporation into virions. Of interest is that the formation of NP helices, which involves the N-terminal 450 amino acids of NP, is dispensable for NP incorporation into VLPs. These findings enhance our understanding of Ebola virus assembly and in so doing move us closer to the identification of targets for the development of antiviral compounds to combat Ebola virus infection.
Sialic Acid on Herpes Simplex Virus Type 1 Envelope Glycoproteins Is Required for Efficient Infection of Cells
Authors: Teuton Jeremy R. , Brandt Curtis R. 
Published: January 2007

ABSTRACT
Herpes simplex virus type 1 (HSV-1) envelope proteins are posttranslationally modified by the addition of sialic acids to the termini of the glycan side chains. Although gC, gD, and gH are sialylated, it is not known whether sialic acids on these envelope proteins are functionally important. Digestion of sucrose gradient purified virions for 4 h with neuraminidases that remove both α2,3 and α2,6 linked sialic acids reduced titers by 1,000-fold. Digestion with a α2,3-specific neuraminidase had no effect, suggesting that α2,6-linked sialic acids are required for infection. Lectins specific for either α2,3 or α2,6 linkages blocked attachment and infection to the same extent. In addition, the mobility of gH, gB, and gD in sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels was altered by digestion with either α2,3 specific neuraminidase or nonspecific neuraminidases, indicating the presence of both linkages on these proteins. The infectivity of a gC-1-null virus, ΔgC2-3, was reduced to the same extent as wild-type virus after neuraminidase digestion, and attachment was not altered. Neuraminidase digestion of virions resulted in reduced VP16 translocation to the nucleus, suggesting that the block occurred between attachment and entry. These results show for the first time that sialic acids on HSV-1 virions play an important role in infection and suggest that targeting virion sialic acids may be a valid antiviral drug development strategy.
Assembly of Hepatitis Delta Virus: Particle Characterization, Including the Ability To Infect Primary Human Hepatocytes
Authors: Gudima Severin , He Yiping , Meier Anja , Chang Jinhong , Chen Rongji , Jarnik Michal , Nicolas Emmanuelle , Bruss Volker , Taylor John 
Published: January 2007

ABSTRACT
Efficient assembly of hepatitis delta virus (HDV) was achieved by cotransfection of Huh7 cells with two plasmids: one to provide expression of the large, middle, and small envelope proteins of hepatitis B virus (HBV), the natural helper of HDV, and another to initiate replication of the HDV RNA genome. HDV released into the media was assayed for HDV RNA and HBV envelope proteins and characterized by rate-zonal sedimentation, immunoaffinity purification, electron microscopy, and the ability to infect primary human hepatocytes. Among the novel findings were that (i) immunostaining for delta antigen 6 days after infection with 300 genome equivalents (GE) per cell showed only 1% of cells as infected, but this was increased to 16% when 5% polyethylene glycol was present during infection; (ii) uninfected cells did not differ from infected cells in terms of albumin accumulation or the presence of E-cadherin at cell junctions; and (iii) sensitive quantitative real-time PCR assays detected HDV replication even when the multiplicity of infection was 0.2 GE/cell. In the future, this HDV assembly and infection system can be further developed to better understand the mechanisms shared by HBV and HDV for attachment and entry into host cells.
A Replication-Competent Adenovirus-Human Immunodeficiency Virus (Ad-HIV)tatand Ad-HIVenvPriming/Tat and Envelope Protein Boosting Regimen Elicits Enhanced Protective Efficacy against Simian/Human Immunodeficiency Virus SHIV89.6PChallenge in Rhesus Macaques
Authors: Demberg Thorsten , Florese Ruth H. , Heath Megan J. , Larsen Kay , Kalisz Irene , Kalyanaraman V. S. , Lee Eun Mi , Pal Ranajit , Venzon David , Grant Richard , Patterson L. Jean , Korioth-Schmitz Birgit , Buzby Adam , Dombagoda Dilani , Montefiori David C. , Letvin Norman L. , Cafaro Aurelio , Ensoli Barbara , Robert-Guroff Marjorie 
Published: January 2007

ABSTRACTWe previously demonstrated that replication-competent adenovirus (Ad)-simian immunodeficiency virus (SIV) recombinant prime/protein boost regimens elicit potent immunogenicity and strong, durable protection of rhesus macaques against SIVmac251. Additionally, native Tat vaccines have conferred strong protection against simian/human immunodeficiency virus SHIV89.6Pchallenge of cynomolgus monkeys, while native, inactivated, or vectored Tat vaccines have failed to elicit similar protective efficacy in rhesus macaques. Here we asked if priming rhesus macaques with replicating Ad-human immunodeficiency virus (HIV)tatand boosting with the Tat protein would elicit protection against SHIV89.6P. We also evaluated a Tat/Env regimen, adding an Ad-HIVenvrecombinant and envelope protein boost to test whether envelope antibodies would augment acute-phase protection. Further, expecting cellular immunity to enhance chronic viremia control, we tested a multigenic group: Ad-HIVtat, -HIVenv, -SIVgag, and -SIVnefrecombinants and Tat, Env, and Nef proteins. All regimens were immunogenic. A hierarchy was observed in enzyme-linked immunospot responses (with the strongest response for Env, followed by Gag, followed by Nef, followed by Tat) and antibody titers (with the highest titer for Env, followed by Tat, followed by Nef, followed by Gag). Following intravenous SHIV89.6Pchallenge, all macaques became infected. Compared to controls, no protection was seen in the Tat-only group, confirming previous reports for rhesus macaques. However, the multigenic group blunted acute viremia by approximately 1 log (P= 0.017), and both the multigenic and Tat/Env groups reduced chronic viremia by 3 and 4 logs, respectively, compared to controls (multigenic,P= 0.0003; Tat/Env,P< 0.0001). The strikingly greater reduction in the Tat/Env group than in the multigenic group (P= 0.014) was correlated with Tat and Env binding antibodies. Since prechallenge anti-Env antibodies lacked SHIV89.6P-neutralizing activity, other functional anti-Env and anti-Tat activities are under investigation, as is a possible synergy between the Tat and Env immunogens.
The Glycoprotein Cytoplasmic Tail of Uukuniemi Virus (
Bunyaviridae
) Interacts with Ribonucleoproteins and Is Critical for Genome Packaging
Authors: Överby Anna K. , Pettersson Ralf F. , Neve Etienne P. A. 
Published: January 2007

ABSTRACT

We have analyzed the importance of specific amino acids in the cytoplasmic tail of the glycoprotein G
N
for packaging of ribonucleoproteins (RNPs) into virus-like particles (VLPs) of
Uukuniemi virus
(UUK virus), a member of the
Bunyaviridae
family. In order to study packaging, we added the G
N
/G
C
glycoprotein precursor (p110) to a polymerase I-driven minigenome rescue system to generate VLPs that are released into the supernatant. These particles can infect new cells, and reporter gene expression can be detected. To determine the role of UUK virus glycoproteins in RNP packaging, we performed an alanine scan of the glycoprotein G
N
cytoplasmic tail (amino acids 1 to 81). First, we discovered three regions in the tail (amino acids 21 to 25, 46 to 50, and 71 to 81) which are important for minigenome transfer by VLPs. Further mutational analysis identified four amino acids that were important for RNP packaging. These amino acids are essential for the binding of nucleoproteins and RNPs to the glycoprotein without affecting the morphology of the particles. No segment-specific interactions between the RNA and the cytoplasmic tail could be observed. We propose that VLP systems are useful tools for analyzing protein-protein interactions important for packaging of viral genome segments, assembly, and budding of other members of the
Bunyaviridae
family.
Radioiodinated versus Radiometal-Labeled Anti–Carcinoembryonic Antigen Single-Chain Fv-Fc Antibody Fragments: Optimal Pharmacokinetics for Therapy
Authors: Kenanova Vania , Olafsen Tove , Williams Lawrence E. , Ruel Nora H. , Longmate Jeffrey , Yazaki Paul J. , Shively John E. , Colcher David , Raubitschek Andrew A. , Wu Anna M. 
Published: January 2007

Abstract
Antibody fragments with optimized pharmacokinetic profiles hold potential for detection and therapy of tumor malignancies. We studied the behavior of three anti–carcinoembryonic antigen (CEA) single-chain Fv-Fc (scFv-Fc) variants (I253A, H310A, and H310A/H435Q; Kabat numbering system) that exhibited differential serum persistence. Biodistribution studies done on CEA-positive tumor xenografted mice revealed that the 111In-labeled I253A fragment with the slowest clearance kinetics (T1/2β, 27.7 h) achieved the highest tumor uptake (44.6% ID/g at 24 h), whereas the radiometal-labeled H310A/H435Q fragment with the most rapid elimination (T1/2β, 7.05 h) reached a maximum of 28.0% ID/g at 12 h postinjection. The H310A protein was characterized by both intermediate serum half-life and tumor uptake. The 111In-based biodistribution studies showed that all three fragments were eliminated primarily through the liver, and hepatic radiometal activity correlated with the rate of fragment clearance. The 111In-labeled H310A/H435Q protein exhibited the highest liver uptake (23.5% ID/g at 24 h). Metabolism of the 125I-labeled scFv-Fc proteins resulted in low normal organ activity. Finally, the 125I/111In biodistribution data allowed for dose estimations, which suggest the 131I-labeled scFv-Fc H310A/H435Q as a promising candidate for radioimmunotherapy. [Cancer Res 2007;67(2):718–26]
Suppression of Mammary Carcinoma Cell Growth by Retinoic Acid: the Cell Cycle Control Gene Btg2 Is a Direct Target for Retinoic Acid Receptor Signaling
Authors: Donato Leslie J. , Suh Jean H. , Noy Noa 
Published: January 2007

Abstract
The anticarcinogenic activities of retinoic acid (RA) are believed to be mediated by the nuclear RA receptor (RAR) and by the RA-binding protein cellular RA-binding protein-II (CRABP-II). In MCF-7 mammary carcinoma cells, growth inhibition by RA entails an early cell cycle arrest followed by induction of apoptosis. Here, we aimed to obtain insights into the initial cell cycle response. We show that a 3- to 5-h RA pulse is sufficient for inducing a robust growth arrest 2 to 4 days later, demonstrating inhibition of the G1-S transition by RA is triggered by immediate-early RAR targets and does not require the continuous presence of the hormone throughout the arrest program. Expression array analyses revealed that RA induces the expression of several genes involved in cell cycle regulation, including the p53-controlled antiproliferative gene B-cell translocation gene, member 2 (Btg2) and the BTG family member Tob1. We show that induction of Btg2 by RA does not require de novo protein synthesis and is augmented by overexpression of CRABP-II. Additionally, we identify a RA response element in the Btg2 promoter and show that the element binds retinoid X receptor/RAR heterodimers in vitro, is occupied by the heterodimers in cells, and can drive RA-induced activation of a reporter gene. Hence, Btg2 is a novel direct target for RA signaling. In concert with the reports that Btg2 inhibits cell cycle progression by down-regulating cyclin D1, induction of Btg2 by RA was accompanied by a marked decrease in cyclin D1 expression. The observations thus show that the antiproliferative activity of RA in MCF-7 cells is mediated, at least in part, by Btg2. [Cancer Res 2007;67(2):609–15]
NKX3.1 Homeodomain Protein Binds to Topoisomerase I and Enhances Its Activity
Authors: Bowen Cai , Stuart August , Ju Jeong-Ho , Tuan Jenny , Blonder Josip , Conrads Thomas P. , Veenstra Timothy D. , Gelmann Edward P. 
Published: January 2007

Abstract
The prostate-specific homeodomain protein NKX3.1 is a tumor suppressor that is commonly down-regulated in human prostate cancer. Using an NKX3.1 affinity column, we isolated topoisomerase I (Topo I) from a PC-3 prostate cancer cell extract. Topo I is a class 1B DNA-resolving enzyme that is ubiquitously expressed in higher organisms and many prokaryotes. NKX3.1 interacts with Topo I to enhance formation of the Topo I-DNA complex and to increase Topo I cleavage of DNA. The two proteins interacted in affinity pull-down experiments in the presence of either DNase or RNase. The NKX3.1 homeodomain was essential, but not sufficient, for the interaction with Topo I. NKX3.1 binding to Topo I occurred independently of the Topo I NH2-terminal domain. The binding of equimolar amounts of Topo I to NKX3.1 caused displacement of NKX3.1 from its cognate DNA recognition sequence. Topo I activity in prostates of Nkx3.1+/− and Nkx3.1−/− mice was reduced compared with wild-type mice, whereas Topo I activity in livers, where no NKX3.1 is expressed, was independent of Nkx3.1 genotype. Endogenous Topo I and NKX3.1 could be coimmunoprecipitated from LNCaP cells, where NKX3.1 and Topo I were found to colocalize in the nucleus and comigrate within the nucleus in response to either γ-irradiation or mitomycin C exposure, two DNA-damaging agents. This is the first report that a homeodomain protein can modify the activity of Topo I and may have implications for organ-specific DNA replication, transcription, or DNA repair. [Cancer Res 2007;67(2):455–64]
Merlin/Neurofibromatosis Type 2 Suppresses Growth by Inhibiting the Activation of Ras and Rac
Authors: Morrison Helen , Sperka Tobias , Manent Jan , Giovannini Marco , Ponta Helmut , Herrlich Peter 
Published: January 2007

AbstractThe small G-protein Ras is a tightly controlled regulator of cell fate. Prolonged or persistent arrest in the activated GTP-loaded state by mutation of Ras as in lung cancer or in a Ras–GTPase-activating protein as in neurofibromatosis type 1 promotes tumorigenesis. We now show that the tumor-suppressor protein merlin (mutated in neurofibromatosis type 2) also controls Ras activity. Systematic analysis of growth factor signaling located the step of merlin interference to the activation of Ras and Rac. Merlin independently uncouples both Ras and Rac from growth factor signals. In the case of Ras, merlin acts downstream of the receptor tyrosine kinase-growth factor receptor binding protein 2 (Grb2)-SOS complex. However, merlin does not bind either SOS or Ras, but it counteracts the ERM (ezrin, radixin, moesin)–dependent activation of Ras, which correlates with the formation of a complex comprising ERM proteins, Grb2, SOS, Ras, and filamentous actin. Because efficient signaling from Ras requires Rac-p21-activated kinase–dependent phosphorylations of Raf and mitogen-activated protein/extracellular signal-regulated kinase kinase, merlin can also inhibit signal transfer from dominantly active Ras mutants. We propose that the interference of merlin with Ras- and Rac-dependent signal transfer represents part of the tumor-suppressive action of merlin. [Cancer Res 2007;67(2):520–7]