bluuebunny/crossref_metadata_2025_split huggingface dataset:
Herpes Simplex Virus 1 Gene Expression Is Accelerated by Inhibitors of Histone Deacetylases in Rabbit Skin Cells Infected with a Mutant Carrying a cDNA Copy of the Infected-Cell Protein No. 0
Authors: Poon Alice P. W. , Liang Yu , Roizman Bernard 
Published: November 2003

ABSTRACT

An earlier report showed that the expression of viral genes by a herpes simplex virus 1 mutant [HSV-1(vCPc0)] in which the wild-type, spliced gene encoding infected-cell protein no. 0 (ICP0) was replaced by a cDNA copy is dependent on both the cell type and multiplicity of infection. At low multiplicities of infection, viral gene expression in rabbit skin cells was delayed by many hours, although ultimately virus yield was comparable to that of the wild-type virus. This defect was rescued by replacement of the cDNA copy with the wild-type gene. To test the hypothesis that the delay reflected a dysfunction of ICP0 in altering the structure of host protein-viral DNA complexes, we examined the state of histone deacetylases (HDACs) (HDAC1, HDAC2, and HDAC3). We report the following. (i) HDAC1 and HDAC2, but not HDAC3, were modified in infected cells. The modification was mediated by the viral protein kinase U
S
3 and occurred between 3 and 6 h after infection with wild-type virus but was delayed in rabbit skin cells infected with HSV-1(vCPc0) mutant, concordant with a delay in the expression of viral genes. (ii) Pretreatment of rabbit skin cells with inhibitors of HDAC activity (e.g., sodium butyrate,
Helminthosporium carbonum
toxin, or trichostatin A) accelerated the expression of HSV-1(vCPc0) but not that of wild-type virus. We conclude the following. (i) In the interval in which HSV-1(vCPc0) DNA is silent, its DNA is in chromatin-like structures amenable to modification by inhibitors of histone deacetylases. (ii) Expression of wild-type virus genes in these cells precluded the formation of DNA-protein structures that would be affected by either the HDACs or their inhibitors. (iii) Since the defect in HSV-1(vCPc0) maps to ICP0, the results suggest that this protein initiates the process of divestiture of viral DNA from tight chromatin structures but could be replaced by other viral proteins in cells infected with a large number of virions.
Strand-Specific RNA Synthesis Defects in a Poliovirus with a Mutation in Protein 3A
Authors: Teterina Natalya L. , Rinaudo Mario S. , Ehrenfeld Ellie 
Published: November 2003

ABSTRACT
Substitution of a methionine residue at position 79 in poliovirus protein 3A with valine or threonine caused defective viral RNA synthesis, manifested as delayed onset and reduced yield of viral RNA, in HeLa cells transfected with a luciferase-containing replicon. Viruses containing these same mutations produced small or minute plaques that generated revertants upon further passage, with either wild-type 3A sequences or additional nearby compensating mutations. Translation and polyprotein processing were not affected by the mutations, and 3AB proteins containing the altered amino acids at position 79 showed no detectable loss of membrane-binding activity. Analysis of individual steps of viral RNA synthesis in HeLa cell extracts that support translation and replication of viral RNA showed that VPg uridylylation and negative-strand RNA synthesis occurred normally from mutant viral RNA; however, positive-strand RNA synthesis was specifically reduced. The data suggest that a function of viral protein 3A is required for positive-strand RNA synthesis but not for production of negative strands.
Quantitation of HLA Class II Protein Incorporated into Human Immunodeficiency Type 1 Virions Purified by Anti-CD45 Immunoaffinity Depletion of Microvesicles
Authors: Trubey Charles M. , Chertova Elena , Coren Lori V. , Hilburn Joanne M. , Hixson Catherine V. , Nagashima Kunio , Lifson Jeffrey D. , Ott David E. 
Published: November 2003

ABSTRACT

Among the many host cell-derived proteins found in human immunodeficiency virus type 1 (HIV-1), HLA class II (HLA-II) appears to be selectively incorporated onto virions and may contribute to mechanisms of indirect imunopathogenesis in HIV infection and AIDS. However, the amount of HLA-II on the surface of HIV-1 particles has not been reliably determined due to contamination of virus preparations by microvesicles containing host cell proteins, including HLA-II. Even rigorous sucrose density centrifugation is unable to completely separate HIV-1 from microvesicles. CD45, a leukocyte integral membrane protein, is found on microvesicles, yet appears to be excluded from HIV-1 particles. Exploiting this observation, we have developed a CD45-based immunoaffinity depletion method for removing CD45-containing microvesicles that yields highly purified preparations of virions. Examination of CD45-depleted HIV-1
MN
by high-pressure liquid chromatography, protein sequencing, and amino acid analyses determined a molar ratio of HLA-II to Gag of 0.04 to 0.05 in the purified virions, corresponding to an estimated average of 50 to 63 native HLA-II complexes (i.e., a dimer of α and β heterodimers) per virion. These values are approximately 5- to 10-fold lower than those previously determined for other virion preparations that contained microvesicles. Our observations demonstrate the utility of CD45 immunoaffinity-based approaches for producing highly purified retrovirus preparations for applications that would benefit from the use of virus that is essentially free of microvesicles.
Deletions in the Transmembrane Domain of a Sindbis Virus Glycoprotein Alter Virus Infectivity, Stability, and Host Range
Authors: Hernandez Raquel , Sinodis Christine , Horton Michelle , Ferreira Davis , Yang Chunning , Brown Dennis T. 
Published: November 2003

ABSTRACT
The alphaviruses are composed of two icosahedral protein shells, one nested within the other. A membrane bilayer derived from the host cell is sandwiched between the protein shells. The protein shells are attached to one another by protein domains which extend one of the proteins of the outer shell through the membrane bilayer to attach to the inner shell. We have examined the interaction of the membrane-spanning domain of one of the membrane glycoproteins with the membrane bilayer and with other virus proteins in an attempt to understand the role this domain plays in virus assembly and function. Through incremental deletions, we have reduced the length of a virus membrane protein transmembrane domain from its normal 26 amino acids to 8 amino acids. We examined the effect of these deletions on the assembly and function of virus particles. We found that progressive truncations in the transmembrane domain profoundly affected production of infectious virus in a cyclic fashion. We also found that membrane composition effects protein-protein and protein-membrane interactions during virus assembly.
COX-2 Induction during Murine Gammaherpesvirus 68 Infection Leads to Enhancement of Viral Gene Expression
Authors: Symensma Tonia L. , Martinez-Guzman DeeAnn , Jia Qingmei , Bortz Eric , Wu Ting-Ting , Rudra-Ganguly Nandini , Cole Steve , Herschman Harvey , Sun Ren 
Published: November 2003

ABSTRACTThe murine gammaherpesvirus 68 (MHV-68 or γHV-68) model provides many advantages for studying virus-host interactions involved in gammaherpesvirus replication, including the role of cellular responses to infection. We examined the effects of cellular cyclooxygenase-2 (COX-2) and its by-product prostaglandin E2(PGE2) on MHV-68 gene expression and protein production following de novo infection of cultured cells. Western blot analyses revealed an induction of COX-2 protein in MHV-68-infected cells but not in cells infected with UV-irradiated MHV-68. Luciferase reporter assays demonstrated activation of theCOX-2promoter during MHV-68 replication. Two nonsteroidal anti-inflammatory drugs, a COX-2-specific inhibitor (NS-398) and a COX-1-COX-2 inhibitor (indomethacin), substantially reduced MHV-68 protein production in infected cells. Inhibition of viral protein expression and virion production by NS-398 was reversed in the presence of exogenous PGE2. Global gene expression analysis using an MHV-68 DNA array showed that PGE2increased production of multiple viral gene products, and NS-398 inhibited production of many of the same genes. These studies suggest that COX-2 activity and PGE2production may play significant roles during MHV-68 de novo infection.
Immunogenicity of Multiple Gene and Clade Human Immunodeficiency Virus Type 1 DNA Vaccines
Authors: Kong Wing-Pui , Huang Yue , Yang Zhi-Yong , Chakrabarti Bimal K. , Moodie Zoe , Nabel Gary J. 
Published: November 2003

ABSTRACT

The ability to elicit an immune response to a spectrum of human immunodeficiency virus type 1 (HIV-1) gene products from divergent strains is a desirable feature of an AIDS vaccine. In this study, we examined combinations of plasmids expressing multiple HIV-1 genes from different clades for their ability to elicit humoral and cellular immune responses in mice. Immunization with a modified Env, gp145ΔCFI, in combination with a Gag-Pol-Nef fusion protein plasmid elicited similar CD4
+
and CD8
+
cellular responses to immunization with either vector alone. Further, when mice were immunized with a mixture of Env from three clades, A, B, and C, together with Gag-Pol-Nef, the overall potency and balance of CD4
+
- and CD8
+
-T-cell responses to all viral antigens were similar, with only minor differences noted. In addition, plasmid mixtures elicited antibody responses comparable to those from individual inoculations. These findings suggest that a multigene and multiclade vaccine, including components from A, B, and C Env and Gag-Pol-Nef, can broaden antiviral immune responses without immune interference. Such combinations of immunogens may help to address concerns about viral genetic diversity for a prospective HIV-1 vaccine.
Characterization of Recombinant Nonecotropic Murine Leukemia Viruses from the Wild Mouse Species
Mus spretus
Authors: Jung Yong Tae , Wu Tiyun , Kozak Christine A. 
Published: November 2003

ABSTRACT

The wild mouse species most closely related to the common laboratory strains contain proviral
env
genes of the xenotropic/polytropic subgroup of mouse leukemia viruses (MLVs). To determine if the polytropic proviruses of
Mus spretus
contain functional genes, we inoculated neonates with Moloney MLV (MoMLV) or amphotropic MLV (A-MLV) and screened for viral recombinants with altered host ranges. Thymus and spleen cells from MoMLV-inoculated mice were plated on
Mus dunni
cells and mink cells, since these cells do not support the replication of MoMLV, and cells from A-MLV-inoculated mice were plated on ferret cells. All MoMLV-inoculated mice produced ecotropic viruses that resembled their MoMLV progenitor, although some isolates, unlike MoMLV, grew to high titers in
M. dunni
cells. All of the MoMLV-inoculated mice also produced nonecotropic virus that was infectious for mink cells. Sequencing of three MoMLV- and two A-MLV-derived nonecotropic recombinants confirmed that these viruses contained substantial substitutions that included the regions of env encoding the surface (SU) protein and the 5′ end of the transmembrane (TM) protein. The 5′ recombination breakpoint for one of the A-MLV recombinants was identified in RNase H. The
M. spretus
-derived
env
substitutions were nearly identical to the corresponding regions in prototypical laboratory mouse polytropic proviruses, but the wild mouse infectious viruses had a more restricted host range. The
M. spretus
proviruses contributing to these recombinants were also sequenced. The seven sequenced proviruses were 99% identical to one another and to the recombinants; only two of the seven had obvious fatal defects. We conclude that the
M. spretus
proviruses are likely to be recent germ line acquisitions and that they contain functional genes that can contribute to the production of replication-competent virus.
Membrane Synthesis, Specific Lipid Requirements, and Localized Lipid Composition Changes Associated with a Positive-Strand RNA Virus RNA Replication Protein
Authors: Lee Wai-Ming , Ahlquist Paul 
Published: November 2003

ABSTRACT

Multifunctional RNA replication protein 1a of brome mosaic virus (BMV), a positive-strand RNA virus, localizes to the cytoplasmic face of endoplasmic reticulum (ER) membranes and induces ER lumenal spherules in which viral RNA synthesis occurs. We previously showed that BMV RNA replication in yeast is severely inhibited prior to negative-strand RNA synthesis by a single-amino-acid substitution in the
ole1w
allele of yeast Δ9 fatty acid (FA) desaturase, which converts saturated FAs (SFAs) to unsaturated FAs (UFAs). Here we further define the relationships between 1a, membrane lipid composition, and RNA synthesis. We show that 1a expression increases total membrane lipids in wild-type (wt) yeast by 25 to 33%, consistent with recent results indicating that the numerous 1a-induced spherules are enveloped by invaginations of the outer ER membrane. 1a did not alter total membrane lipid composition in wt or
ole1w
yeast, but the
ole1w
mutation selectively depleted 18-carbon, monounsaturated (18:1) FA chains and increased 16:0 SFA chains, reducing the UFA-to-SFA ratio from ∼2.5 to ∼1.5. Thus,
ole1w
inhibition of RNA replication was correlated with decreased levels of UFA, membrane fluidity, and plasticity. The
ole1w
mutation did not alter 1a-induced membrane synthesis, 1a localization to the perinuclear ER, or colocalization of BMV 2a polymerase, nor did it block spherule formation. Moreover, BMV RNA replication templates were still recovered from cell lysates in a 1a-induced, 1a- and membrane-associated, and nuclease-resistant but detergent-susceptible state consistent with spherules. However, unlike nearby ER membranes, the membranes surrounding spherules in
ole1w
cells were not distinctively stained with osmium tetroxide, which interacts specifically with UFA double bonds. Thus, in
ole1w
cells, spherule-associated membranes were locally depleted in UFAs. This localized UFA depletion helps to explain why BMV RNA replication is more sensitive than cell growth to reduced UFA levels. The results imply that 1a preferentially interacts with one or more types of membrane lipids.
Functional Domain Structure of Human T-Cell Leukemia Virus Type 2 Rex
Authors: Narayan Murli , Younis Ihab , D'Agostino Donna M. , Green Patrick L. 
Published: November 2003

ABSTRACT

The Rex protein of human T-cell leukemia virus (HTLV) acts posttranscriptionally to induce the cytoplasmic expression of the unspliced and incompletely spliced viral RNAs encoding the viral structural and enzymatic proteins and is therefore essential for efficient viral replication. Rex function requires nuclear import, RNA binding, multimerization, and nuclear export. In addition, it has been demonstrated that the phosphorylation status of HTLV-2 Rex (Rex-2) correlates with RNA binding and inhibition of splicing in vitro. Recent mutational analyses of Rex-2 revealed that the phosphorylation of serine residues 151 and 153 within a novel carboxy-terminal domain is critical for function in vivo. To further define the functional domain structure of Rex-2, we evaluated a panel of Rex-2 mutants for subcellular localization, RNA binding capacity, multimerization and
trans
-dominant properties, and the ability to shuttle between the nucleus and the cytoplasm. Rex-2 mutant S151A,S153A, which is defective in phosphorylation and function, showed diffuse cytoplasmic staining, whereas mutant S151D,S153D, previously shown to be functional and in a conformation corresponding to constitutive phosphorylation, displayed increased intense speckled staining in the nucleoli. In vivo RNA binding analyses indicated that mutant S151A,S153A failed to efficiently bind target RNA, while its phosphomimetic counterpart, S151D,S153D, bound twofold more RNA than wild-type Rex-2. Taken together, these findings provide direct evidence that the phosphorylation status of Rex-2 is linked to cellular trafficking and RNA binding capacity. Mutants with substitutions in either of the two putative multimerization domains or in the putative activation domain-nuclear export signal displayed a dominant negative phenotype as well as defects in multimerization and nucleocytoplasmic shuttling. Several carboxy-terminal mutants that displayed wild-type levels of phosphorylation and localized to the nucleolus were also partially impaired in shuttling. This is consistent with the hypothesis that the carboxy terminus of Rex-2 contains a novel domain that is required for efficient shuttling. This work thus provides a more detailed functional domain map of Rex-2 and further insight into its regulation of HTLV replication.
Binding of Human Immunodeficiency Virus Type 1 to Immature Dendritic Cells Can Occur Independently of DC-SIGN and Mannose Binding C-Type Lectin Receptors via a Cholesterol-Dependent Pathway
Authors: Gummuluru Suryaram , Rogel Mark , Stamatatos Leonidas , Emerman Michael 
Published: November 2003

ABSTRACT

Interactions of human immunodeficiency virus type 1 (HIV-1) with immature dendritic cells (DC) are believed to be multifactorial and involve binding to the CD4 antigen, DC-specific ICAM-3-grabbing nonintegrin (DC-SIGN), mannose binding C-type lectin receptors (MCLR), and heparan sulfate proteoglycans (HSPG). In this study we assessed the relative contributions of these previously defined virus attachment factors to HIV binding and accumulation in DC and the subsequent transfer of the bound virus particle to CD4
+
T cells. Using competitive inhibitors of HIV-1 attachment to DC, we have identified the existence of DC-SIGN-, MCLR-, and HSPG-independent mechanism(s) of HIV attachment and internalization. Furthermore, virus particles bound by DC independently of CD4, DC-SIGN, MCLR, and HSPG are efficiently transmitted to T cells. Treatment of virus particles with the protease subtilisin or treatment of immature DC with trypsin significantly reduced virus binding, thus demonstrating the role of HIV envelope glycoprotein interactions with unidentified DC-surface factor(s). Finally, this DC-mediated virus binding and internalization are dependent on lipid rafts. We propose that pathways to HIV-1 attachment and uptake in DC exhibit functional redundancy; that is, they are made up of multiple independent activities that can, at least in part, compensate for one another.
Infection with Multiple Human Immunodeficiency Virus Type 1 Variants Is Associated with Faster Disease Progression
Authors: Sagar Manish , Lavreys Ludo , Baeten Jared M. , Richardson Barbra A. , Mandaliya Kishorchandra , Chohan Bhavna H. , Kreiss Joan K. , Overbaugh Julie 
Published: November 2003

ABSTRACTHuman immunodeficiency virus type 1 (HIV-1)-infected individuals develop a genetically diverse virus population over time, but often only a limited number of viral variants are transmitted from a chronic carrier to a newly infected person. Interestingly, many women but few men are infected by multiple HIV-1 variants from a single partner. To determine whether the complexity of the infecting virus population influences clinical outcome, we examined viral diversity in the HIV-1 envelope sequences present at primary infection in 156 women from Kenya for whom we had follow-up data on viral RNA levels and CD4 T-cell counts. Eighty-nine women had multiple viral genotypes, while 67 women had a single genotype at primary infection. Women who acquired multiple viral genotypes had a significantly higher viral load (median, 4.84 versus 4.64 log10copies/ml,P= 0.04) and a significantly lower CD4+-T-cell count (median, 416 versus 617 cells/mm3,P= 0.01) 4 to 24 months after infection compared to women who were infected with a single viral genotype. These studies suggest that early HIV-1 genetic diversity is linked to faster disease progression.
Performance of clinical referral criteria for bone densitometry in patients under 65 years of age assessed by spine bone mineral density
Authors: Kayan K , de Takats D , Ashford R , Kanis J A , McCloskey E V 
Published: November 2003

Abstract

Background
A case finding strategy based on a number of established risk factors has been suggested by Royal College of Physicians’ (RCP) guidelines to optimise bone densitometry referrals for assessment of osteoporosis.

Objective
The performance of clinical referral criteria was examined in women and men aged &lt;65 years referred for bone mineral density (BMD) assessment.

Study design
Cross sectional observational study over six months.

Results
Though BMD tended to be lower in patients with multiple criteria for referral, differences from those referred with a single criterion were not statistically significant. The overall prevalence of osteoporosis was higher than expected in both sexes, 11.6% in women and 27.5% in men (expected prevalences were 8% and &lt;1% respectively). BMD was significantly lower in patients referred with a single criterion compatible with the RCP guidelines than in age matched controls or in those patients referred with non-RCP criteria (mean (SD) Z score –0.47(1.38) v 0.35(1.41), p&lt;0.001). Low body mass index was also significantly associated with a lower than expected BMD. In contrast, spine BMD was higher than expected in those with self reported back pain, loss of height, or spinal curvature (p = NS).

Conclusion
Most of the criteria recommended by the RCP performed well in identifying relatively younger patients with low BMD and osteoporosis. However, prior fractures and corticosteroid use did not reach statistical significance probably due to inclusion of all energy fractures, and current or past steroid use of unspecified dose or duration. Criteria like loss of height and/or spine curvature perform relatively poorly, reflecting the need for further investigation to better identify those needing BMD assessment.
Hereditary hyperferritinaemia-cataract syndrome and differential diagnosis of hereditary haemochromatosis
Authors: Sanders S J , Suri M , Ross I 
Published: November 2003

Abstract
Hereditary hyperferritinaemia-cataract syndrome (HHCS) is a rare differential diagnosis of hereditary haemochromatosis. It should be suspected in patients with raised ferritin levels, but no evidence of iron overload, and in the absence of mutations in the HFE gene. Awareness of this condition prevents unnecessary liver biopsies and allows accurate genetic counselling since HHCS is an autosomal dominant disorder. The danger of treating these patients by phlebotomy in the same manner as those with hereditary haemochromatosis is highlighted.
Systemic absorption of FD&C blue dye associated with patient mortality
Authors: Gaur S , Sorg T , Shukla V 
Published: November 2003

Abstract
The addition of FD&C blue dye to enteral feeds is a common practice in hospitals to detect aspiration. However, the degree of systemic absorption and safety of this dye in critically ill patients has not been studied. A patient with sepsis who died after systemic absorption of FD&C blue dye No1 is described.