Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Varicella zoster virus encodes a thymidine kinase responsible for the activation of antiherpetic nucleoside prodrugs such as acyclovir. In addition, herpes virus thymidine kinases are being explored in gene/chemotherapy strategies aimed at developing novel antitumor therapies. To investigate and improve compound selectivity, we report here structure-based site-directed mutagenesis studies of varicella zoster virus thymidine kinase (VZVTK). Earlier reports showed that mutating residues at the core of the VZVTK active site invariably destroyed activity; hence, we targeted more distal residues. Based on the VZVTK crystal structure, we constructed six mutants (E59S, R84V, H97Y/A, and Y21H/E) and tested substrate activity and competitive inhibition for several compound series. All VZVTK mutants tested retained significant phosphorylation activity with dThd as substrate, apart from Y21E (350-fold diminution in the k(cat)/K(m)). Some mutations give slightly improved affinities: bicyclic nucleoside analogs (BCNAs) with a p-alkyl-substituted phenyl group seem to require aromatic ring stacking interactions with residue 97 for optimal inhibitory effect. Mutation Y21E decreased the IC(50) value for the BCNA 3-(2'-deoxy-beta-D-ribofuranosyl)-6-octyl-2,3-dihydrofuro[2,3-d]pyrimidin-2-one (Cf1368) 4-fold, whereas mutation Y21H increased the IC(50) value by more than 15-fold. These results suggest that residue 21 is important for BCNA selectivity and might explain why HSV1TK is unable to bind BCNAs. Other mutants, such as the E59S and R84V thymidine kinases, which in wild-type VZVTK stabilize the dimer interface, give opposite results regarding the level of sensitivity to BCNAs. The work described here shows that distal mutations that affect the VZVTK active-site may help in the design of more selective substrates for gene suicide therapy or as anti-varicella zoster virus drugs.
Mol Pharmacol 2006 Jun
PMID:Mutations distal to the substrate site can affect varicella zoster virus thymidine kinase activity: implications for drug design. 1655 72

Aim-To evaluate the possible involvement of lymphotropic herpes viruses in Castleman's disease.Methods-Archival formalin fixed, paraffin wax embedded biopsy specimens from 16 HIV negative patients (11 with localised and five of multicentric disease) were studied. Epstein-Barr virus (EBV), human herpes virus-6 (HHV-6) and human herpes virus-8 (HHV-8) DNA was detected using PCR. PCR was also used to characterise the EBV genomes and the clonal status of the lesions.Results-EBV sequences were identified in nine (56%) cases. The main EBV genotype detected was type 1. Two (12%) cases were positive for both HHV-6 and EBV sequences. HHV-8 sequences were detected in one case of localised Castleman's disease, the sequence of which differed from that of the HHV-8 prototype. No clonal immunoglobulin gene rearrangements were found.Conclusions-EBV DNA was detected in a substantial proportion of cases, suggesting that it may have a role in the pathogenesis of Castleman's disease, unlike HHV-6 which was detected rarely. This is the first report of HHV-8 specific sequences in the localised from of the disease.
Clin Mol Pathol 1996 Aug
PMID:Lymphotropic herpes virus (EBV, HHV-6, HHV-8) DNA sequences in HIV negative Castleman's disease. 1669 81

Activity-dependent neuroprotective protein (ADNP) is essential for brain formation. Here, we investigated the potential neuroprotective effects of recombinant ADNP under stress conditions. The human ADNP cDNA was sub-cloned into a vector that contains VP22, a Herpes virus protein that may allow penetration of fused proteins through cellular membranes. When incubated with pheochromocytoma (PC12) cells, a neuronal model, VP22-ADNP was associated with the cells after a 25-min incubation period. Pre-incubation with VP22-ADNP enriched protein fractions protected against beta amyloid peptide toxicity and oxidative stress (H2O2) in PC12 cells. VP22 by itself was devoid of protective activity. Furthermore, the pro-apoptotic protein p53 increased by 3.5-fold from control levels in the presence of H2O2, while treatment with VP22-ADNP prior to H2O2 exposure significantly reduced the p53 protein levels. ADNP expression was previously shown to oscillate as a function of the estrus cycle in the mouse arcuate nucleus, these oscillations are now correlated with increased cellular protection.
Mol Cell Endocrinol 2006 Jun 27
PMID:Recombinant activity-dependent neuroprotective protein protects cells against oxidative stress. 1670 95

Kaposi sarcoma Herpes virus (KSHV), also known as human Herpes virus 8 (HHV8), can persist as episome in target cells. The latency-associated nuclear antigen 1 (LANA-1) is a key component of the latency process, and may be a functional equivalent of the EBNA-1 protein of Epstein-Barr virus. EBNA-1 can subdue immune recognition by virtue of a long glycine and alanine-rich repeat, which interferes with the proteasomal degradation of EBNA-1 and in this way averts the presentation of antigenic peptides derived from it. LANA-1 contains a strongly acidic-repeat region of approximately 580 amino acids, which consists almost exclusively of aspartic acid, glutamine, and glutamic acid residues. The LANA-1 repeat is not similar to the EBNA-1 Gly-Ala-rich repeat. We demonstrate that this acidic region could inhibit antigen processing in cis. Upon transfection of expression vectors containing LANA-1-eGFP fusion genes the cells did not present an ovalbumin-derived H2K(b)-restricted CTL epitope inserted at the carboxyl terminus of the GFP reporter. Deletion of the central acidic-repeat region of LANA-1 abolished the capacity of LANA-1 to block antigen presentation. Similar to the EBNA-1-derived Gly-Ala-rich repeat, the LANA-1 repeat does not inhibit presentation in trans: co-transfection of LANA-1 expression vectors does not inhibit presentation of the ova epitope from the GFP(Ova) fusion protein. These data demonstrate for the first time that the acidic-repeat region of LANA-1 could function as an in cis acting inhibitor of antigen presentation. This may contribute to the immune evasion of cells latently infected by KSHV.
Mol Immunol 2007 Feb
PMID:In cis inhibition of antigen processing by the latency-associated nuclear antigen I of Kaposi sarcoma herpes virus. 1682 98

Homogeneous polymerase chain reaction (PCR) technology is being used increasingly in the diagnosis of infectious disease. The sensitivity and specificity of PCR is being coupled to the ease-of-use and multiplexing capacity of homogeneous methodologies to provide rapid and accurate differential diagnoses. This technology is applicable to the diagnosis of infections with the human herpes viruses, herpes simplex virus 1 (HSV 1), HSV 2 and varicella-zoster virus (VZV). Our aim was to develop and evaluate a homogeneous PCR assay which combines the following features: the assay can detect and distinguish HSV types 1 and 2 and VZV, can be performed on untreated clinical samples, contains internal control reagents to monitor for inhibitors in the sample and allows automatic assignment of viral genotypes. Primers and probes specific for HSV and VZV genes were combined and optimized in a multiplex PCR. An internal control was designed which allowed use of the VZV primers and a human factor V gene DNA template. The assay was evaluated on an initial cohort of 66 clinical swab samples, with results determined by visual inspection of melt curves. Parameters obtained from this study were used to assign genotypes automatically to a second group of 85 clinical swab samples. Optimization of reagents produced melt curve peaks of sufficient height and symmetry for automatic genotype assignment. In the initial cohort of 66 samples, 63 returned concordant results, one sample produced an aberrant peak due to sequence variation and the remaining two samples were positive on re-test. Automatic genotype assignment of the second group of 85 samples resulted in correct identification of 79 samples, with two further aberrant peaks, and two samples positive on retest. The development of this assay should facilitate the rapid detection of herpes viruses from clinical swab samples.
Mol Cell Probes 2007 Feb
PMID:Development of an internally controlled, homogeneous polymerase chain reaction assay for the simultaneous detection and discrimination of herpes simplex virus types 1 and 2 and varicella-zoster virus. 1696 23

In double-stranded DNA bacteriophages the viral DNA is translocated into an empty prohead shell by a powerful ATP-driven motor assembled at the unique portal vertex. Terminases consisting of two to three packaging-related ATPase sites are central to the packaging mechanism. But the nature of the key translocating ATPase, stoichiometry of packaging motor, and basic mechanism of DNA encapsidation are poorly understood. A defined phage T4 packaging system consisting of only two components, proheads and large terminase protein (gp17; 70 kDa), is constructed. Using the large expanded prohead, this system packages any linear double-stranded DNA, including the 171 kb T4 DNA. The small terminase protein, gp16 (18 kDa), is not only not required but also strongly inhibitory. An ATPase activity is stimulated when proheads, gp17, and DNA are actively engaged in the DNA packaging mode. No packaging ATPase was stimulated by the N-terminal gp17-ATPase mutants, K166G (Walker A), D255E (Walker B), E256Q (catalytic carboxylate), D255E-E256D and D255E-E256Q (Walker B and catalytic carboxylate), nor could these sponsor DNA encapsidation. Experiments with the two gp17 domains, N-terminal ATPase domain and C-terminal nuclease domain, suggest that terminase association with the prohead portal and communication between the domains are essential for ATPase stimulation. These data for the first time established an energetic linkage between packaging stimulation of N-terminal ATPase and DNA translocation. A core pathway for the assembly of functional DNA translocating motor is proposed. Since the catalytic motifs of the N-terminal ATPase are highly conserved among >200 large terminase sequences analyzed, these may represent common themes in phage and herpes viral DNA translocation.
J Mol Biol 2006 Nov 03
PMID:The DNA translocating ATPase of bacteriophage T4 packaging motor. 1698 27

Oncolytic viruses based on herpes simplex virus type 1 (HSV-1) are able to infect and lyse a variety of malignant cell lines. However, there is variability in the degree of tumor susceptibility, and the cancer cell determinants of HSV sensitivity are poorly defined. Nectin-1 is a cell surface adhesion molecule that functions as a cellular receptor to HSV envelope glycoprotein D (gD). We assessed tumor nectin-1 expression as a predictor of oncolytic HSV sensitivity. A panel of human squamous carcinoma cell lines was evaluated for viral entry, replication, and cytotoxicity to an attenuated, replication-competent, oncolytic HSV (NV1023). Potential tumor determinants of HSV sensitivity were assessed, including nectin-1, herpes viral entry mediator, total gD receptor expression, S-phase fraction, and doubling time. Significant correlations between nectin-1 expression measured by quantitative fluorescence-activated cell sorting and viral sensitivity measures were identified using Pearson's coefficients. Cancer cell nectin-1 receptor blockade and nectin-1 transfection led to inhibition and enhancement of NV1023 viral entry, respectively. Cell lines with varying nectin-1 expression showed corresponding sensitivity to NV1023 therapy in vivo. Immunohistochemistry for nectin-1 was inversely related to E-cadherin staining, suggesting increased herpes sensitivity of E-cadherin-deficient tumors. These results suggest that nectin-1 may be used as a marker to predict the sensitivity of a tumor to herpes oncolytic therapy.
Mol Ther 2007 Jan
PMID:Nectin-1 expression by squamous cell carcinoma is a predictor of herpes oncolytic sensitivity. 1716 67

Peripheral neuropathy is a common medical problem with numerous aetiologies. Unfortunately, for the majority of cases there is no available medical solution for the underlying cause, and the only option is to try to treat the resulting symptoms. Treatment options exist when neuropathy results in positive symptoms such as pain, but there is a significant lack of treatments for negative symptoms such as numbness and weakness. Systemic application of growth factor peptides has shown promise in protecting nerves from neuropathic insults in preclinical animal studies, but translation into human trials has been problematic and disappointing. Significant advancements have been made in the past few years in utilising gene therapy approaches to treat peripheral neuropathy by expressing neuroprotective gene products either systemically or in specific nervous tissues. For example, plasmids expressing vascular endothelial growth factor injected into muscle, or herpes-simplex-virus-based vectors expressing neurotrophin gene products delivered to dorsal root ganglion neurons, have been used to protect peripheral nerve function in animal models of diabetes-associated peripheral neuropathy. Many published studies support the feasibility of this approach, although several questions still need to be addressed as gene therapy to treat peripheral neuropathy moves out of the laboratory and into the clinic.
Expert Rev Mol Med 2007 Mar 19
PMID:The therapeutic potential of gene transfer for the treatment of peripheral neuropathies. 1736 56

Pyrococcus furiosus is a hyperthermophilic archaeal microorganism found near deep-sea thermal vents and its optimal growth temperature of 100 degrees C. Recently, a 38.8-kDa protein from P. furiosus DSM 3638 was isolated and characterized. Electron microscopy revealed that this protein aggregated as spheres of approximately 30 nm in diameter, which we designated P. furiosus virus-like particles (PfVs). X-ray crystallographic analysis at 3.6-A resolution revealed that each PfV consisted of 180 copies of the 38.8-kDa protein and retained T=3 icosahedral symmetry, as is often the case in spherical viruses. The total molecular mass of each particle was approximately 7 MDa. An examination of capsid structures suggested strong evolutionary links among PfV, tailed double-stranded DNA bacteriophages, and herpes viruses. The similar three-dimensional structures of the various coat proteins indicate that these viral capsids might have originated and evolved from a common ancestor. The structure of PfV provides a previously undescribed example of viral relationships across the three domains of life (Eukarya, Bacteria, and Archaea).
J Mol Biol 2007 May 18
PMID:The crystal structure of a virus-like particle from the hyperthermophilic archaeon Pyrococcus furiosus provides insight into the evolution of viruses. 1739 65

The latency-associated nuclear antigen (LANA-1) of Human Herpes Virus 8 (HHV-8), alternatively called Kaposi Sarcoma Herpes Virus (KSHV) is constitutively expressed in all HHV-8 infected cells. LANA-1 accumulates in well-defined foci that co-localize with the viral episomes. We have previously shown that these foci are tightly associated with the borders of heterochromatin 1. We have also shown that exogenously expressed LANA-1 causes an extensive re-organization of Hoechst 33248 DNA staining patterns of the nuclei in non-HHV-8 infected cells 2. Here we show that this effect includes the release of the bulk of DNA from heterochromatic areas, in both human and mouse cells, without affecting the overall levels of heterochromatin associated histone H3 lysine 9 tri-methylation (3MK9H3). The release of DNA from the heterochromatic chromocenters in LANA-1 transfected mouse cells co-incides with the dispersion of the chromocenter associated methylcytosin binding protein 2 (MECP2). The localization of 3MK9H3 to the remnants of the chromocenters remains unaltered. Moreover, exogeneously expressed LANA-1 leads to the relocation of the chromocenters to the nuclear periphery, indicating extensive changes in the positioning of the chromosomal domains in the LANA-1 harboring interphase nucleus. Using a series of deletion mutants we have shown that the chromatin rearranging effects of LANA-1 require the presence of a short (57 amino acid) region that is located immediately upstream of the internal acidic repeats. This sequence lies within the previously mapped binding site to histone methyltransferase SUV39H1. We suggest that the highly concentrated LANA-1, anchored to the host genome in the nuclear foci of latently infected cells and replicated through each cell generation, may function as "epigenetic modifier". The induction of histone modification in adjacent host genes may lead to altered gene expression, thereby contributing to the viral oncogenesis.
Mol Cancer 2007 Apr 13
PMID:HHV-8 encoded LANA-1 alters the higher organization of the cell nucleus. 1743 7


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