The varicella-zoster virus major transactivator, IE62, contains a potent N-terminal acidic transcriptional activation domain (TAD). Our experiments revealed that the minimal IE62 TAD encompasses amino acids (aa) 19 to 67. We showed that the minimal TAD interacts with the human Mediator complex. Site-specific mutations revealed residues throughout the minimal TAD that are important for both activation and Mediator interaction. The TAD interacts directly with aa 402 to 590 of the MED25 subunit, and site-specific TAD mutations abolished this interaction. Two-dimensional nuclear magnetic resonance spectroscopy revealed that the TAD is intrinsically unstructured. Our studies suggest that transactivation may involve the TAD adopting a defined structure upon binding MED25.Varicella-zoster virus (VZV) is a ubiquitous pathogen that causes varicella (chickenpox) in primary lytic infection and zoster (shingles) during reactivation from latent infection (5). The viral genome is approximately 125 kb in size and encodes at least 71 unique open reading frames. The VZV IE62 protein, which contains 1,310 amino acids (aa), is the major viral transactivator and is essential for viral growth (5, 21). The focus of this work, the IE62 acidic transcriptional activation domain (TAD), was previously mapped to the extreme N terminus of the protein (4,19). This acidic domain is not present in herpes simplex virus type 1 ICP4 (23, 29). The IE62 TAD shows some compositional similarity (containing primarily aliphatic and acidic residues) to the 81-aa herpes simplex virus type 1 VP16 TAD; however, the two TADs share minimal sequence homology (3.9% identity and 5.9% similarity). Furthermore, the IE62 TAD is less acidic than the VP16 TAD, with a calculated isoelectric point of ϳ4.3, compared to ϳ3.4 for the VP16 TAD (http://us.expasy.org/tools/protparam .html). Despite the identification and initial characterization of this important domain some 15 years ago (4, 19), the cellular target or targets of the IE62 TAD remained elusive. Recent work from this laboratory indicates that one target of the IE62 TAD is the human mediator of transcription (31).Mediator consists of approximately 30 subunits (MED1 to MED30) that are in large part conserved from yeast to human. These subunits form head, middle, tail, and CDK submodules, although the localization of MED23-27 is not yet assigned (2, 17). Mediator is required for most PolII-mediated transcription, as it acts as a bridging molecule between activators and PolII. In the current model of activated transcription, Mediator is recruited to the promoter by the TADs of activators. This allows further recruitment of general transcription factors and PolII, resulting in preinitiation-complex assembly and subsequent activated transcription (17). Yang et al. (31) found that both full-length IE62 and a 107-aa fragment containing the IE62 TAD can capture Mediator containing ectopically expressed Flag-tagged MED25 and that upon VZV infection, Mediator is recruited to viral replication compartments within infect...
Most West Nile virus (WNV) infections are asymptomatic, but some lead to neuroinvasive disease with symptoms ranging from disorientation to paralysis and death. Evidence from animal models suggests that neuroinvasive infections may arise as a consequence of impaired immune protection. However, other data suggest that neurologic symptoms may arise as a consequence of immune mediated damage. We demonstrate that elevated immune responses are present in neuroinvasive disease by directly characterizing WNV-specific T cells in subjects with laboratory documented infections using human histocompatibility leukocyte antigen (HLA) class II tetramers. Subjects with neuroinvasive infections had higher overall numbers of WNV-specific T cells than those with asymptomatic infections. Independent of this, we also observed age related increases in WNV-specific T cell responses. Further analysis revealed that WNV-specific T cell responses included a population of atypically polarized CXCR3+CCR4+CCR6- T cells, whose presence was highly correlated with neuroinvasive disease. Moreover, a higher proportion of WNV-specific T cells in these subjects co-produced interferon-γ and interleukin 4 than those from asymptomatic subjects. More globally, subjects with neuroinvasive infections had reduced numbers of CD4+FoxP3+ Tregs that were CTLA4 positive and exhibited a distinct upregulated transcript profile that was absent in subjects with asymptomatic infections. Thus, subjects with neuroinvasive WNV infections exhibited elevated, dysregulated, and atypically polarized responses, suggesting that immune mediated damage may indeed contribute to pathogenic outcomes.
An equation proposed by Darken, including the thermodynamic factor and tracer diffusion coefficients of solvent and solute, was adopted to correlate the diffusion coefficients for naphthalene and dimethylnaphthalene isomers in supercritical carbon dioxide and the correlated results were compared with the experimental data. IML equation of state with mixing rules and combining rules containing two adjustable interaction parameters were used for calculation of the thermodynamic factor. By using the interaction parameters adjusted to the solubility data, the concentration dependence of diffusion coefficients and their anomaly near the critical point of carbon dioxide can be quantitatively represented. In order to improve the reliability of experimental results, some re-measured diffusion coefficient data for naphthalene, 2,6-and 2,7-dimethylnaphthalene at 308.2 K, and new data for naphthalene at 318.2 K and for 2,3-dimethylnaphthalene at 308.2 K are presented.2
A new method for intracranial monitoring of brain electrical activity by means of an intra-arterial guide wire as electrode is described. We carried out intracranial electro-encephalography (EEG) using an insulated Seeker Lite-10 guide wire 18 times in 14 patients: ten times in 6 patients with cerebral arteriovenous malformation (AVM) before embolization, and another 8 times in 8 patients with epilepsy. In all cases, a 2-5 times stronger high voltage potential EEG compared with scalp EEG could be recorded. In 3 patients with complex partial epilepsy, intra-arterial (IA) EEG was recorded under subdural strip electrode monitoring, and IAEEG at the sphenoidal portion of the middle cerebral artery was compared with subdural electrode recordings. Frequent interictal spike discharges recorded with subdural electrodes in the lesional medial temporal lobe were simultaneously visible on IAEEG recording. This method is equivalent to that using a semi-invasive electrode, but ECoG recording can be performed at angiography. IAEEG is a method of electrode recording that has the possibility of clinical application.
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