Role of capsid sequence and immature nucleocapsid proteins p9 and p15 in Human Immunodeficiency Virus type 1 genomic RNA dimerization

AbstractHIV-1 genomic RNA (gRNA) dimerization is important for viral infectivity and is regulated by proteolytic processing of the Gag precursor protein (Pr55gag) under the direction of the viral protease. The processing occurs in successive steps and, to date, the step associated with formation of a wild-type (WT) level of gRNA dimers has not been identified. The primary cleavage divides Pr55gag into two proteins. The C-terminal polypeptide is termed NCp15 (NCp7–p1–p6) because it contains the nucleocapsid protein (NC), a key determinant of gRNA dimerization and packaging. To examine the importance of precursor polypeptides NCp15 and NCp9 (NCp7–p1), we introduced mutations that prevented the proteolytic cleavages responsible for the appearance of NCp9 or NCp7. Using native Northern blot analysis, we show that gRNA dimerization was impaired when both the secondary (p1–p6) and tertiary (p7–p1) cleavage sites of NCp15 were abolished, but unaffected when only one or the other site was abolished. Though processing to NCp9 therefore suffices for a WT level of gRNA dimerization, we also show that preventing cleavage at the p7–p1 site abolished HIV-1 replication. To identify the minimum level of protease activity compatible with a WT level of gRNA dimers, we introduced mutations Thr26Ser and Ala28Ser in the viral protease to partially inactivate it, and we prepared composite HIV-1 resulting from the cotransfection of various ratios of WT and protease-inactive proviral DNAs. The results reveal that a 30% processing of Pr55gag into mature capsid proteins (CA/CA-p2) yielded a WT level of gRNA dimers, while a 10% Pr55gag processing hardly increased gRNA dimerization above the level seen in protease-inactive virions. We found that full gRNA dimerization required less than 50% WT NC in complementation asssays. Finally, we show that if we destroy alpha helix 1 of the capsid protein (CA), gRNA dimerization is impaired to the same extent as when the viral protease is inactivated. Cotransfection studies show that this CA mutation, in contrast to the NC-disabling mutations, has a dominant negative effect on HIV-1 RNA dimerization, viral core formation, and viral replication. This represents the first evidence that a capsid mutation can affect HIV-1 RNA dimerization

Erratum to: Delta rhythmicity is a reliable EEG biomarker in Angelman syndrome: a parallel mouse and human analysis

After publication of our article [1], we became aware that there were two minor data loading and analysis scripting errors in the human EEG data processing pipeline. These errors affected the channel loading/grouping and sleep/ wake coding of EEG data. We have re-analysed all the data affected by these errors. The errors do not affect any interpretations or conclusions, thus no changes to the text are required apart from correcting p values and raw values affected by the errors. There are no changes to statistical significance or lack-thereof. The errors affect data presented in Fig. 3, Fig. 4, Fig. 5, and Additional file 3: Figure S3 and thus we have re-plotted these figures (see below)

Power Line Arbitrary Waveform Generator

Import 05/08/2014Tato bakalářská práce je zaměřena na generování libovolných průběhů napájecích napětí a simulaci poruchových stavů zdroje Kikusui PCR 1000 LA. V práci jsem se věnoval jak teoretickému popisu, tak praktickým zapojením a programování napájecích průběhů. V závěru jsem zhodnotil dosažené výsledky.This work is focused on generating abitrary waveform supply voltages and simulation of fault conditions Kikusui PCR 1000 LA. In my work I paid attention to theoretical description, practical wiring and programming of the supply waveforms. In the end, I reviewed the results.460 - Katedra informatikyvýborn

Conformational changes of polyomavirus during cell entry

Similar to other non-enveloped viruses, the mechanism of cell entry for polyomaviruses is poorly understood. The polyomavirus capsid is an icosahedron composed of 72 pentamers of the major capsid protein VP1. There is one copy of minor capsid proteins, VP2 or VP3, at the center of each pentamer. According to previous studies, polyomavirus cell entry is a multi-step process which includes: 1) VP1 binding to sialic acid (SA) on the surface of host cells, 2) interaction of VP1 with alpha4beta1 integrin and 3) subsequent cell penetration. Biochemical studies have shown that SA alters polyomavirus protease sensitivity, suggesting a conformational change. The aim of this study was to determine these conformational changes at the molecular level. Therefore, we used single particle cryo-electron microscopy to construct 3D maps of wild type (WT) murine polyomavirus, WT bound to SA, a mutant with a disrupted integrin binding site, and the mutant bound to SA. Our results reveal that in both WT and mutant viruses, a significant conformational change happens after binding with SA which is seen as an additional ring of density inside the virus. Moreover some negative densities are seen in the difference map of WT and WT bound with SA, which suggests movement of some viral proteins after binding with SA

Ictal Forced Repetitive Swearing in Frontal Lobe Epilepsy: Case report and review of the literature

Introduction. Dominant presentation of ictal forced repetitive swearing has been rarely addressed and could be misdiagnosed

Life Quality Assessment Among Patients with Vitiligo: Comparison of Married and Single Patients in Iran

Background and Aims: Vitiligo is known to affect the quality of social and personal life in some countries. This study aims to assess the quality of life (QOL) in vitiligo sufferers among the Iranian population and to evaluate its relation with different variables. Methods: One hundred vitiligo patients answered a questionnaire based on the Dermatology Life Quality Index (DLQI). Results: The mean DLQI score was 8.16. There were statistically significant relationships between DLQI scores and marital status, skin phototype, and disease extension independently. Conclusions: This study shows that vitiligo has a major impact on the QOL of patients in Iran. Hence dermatologists should pay attention to the psychological effects of this cosmetic disease and try to decrease its extension and disfiguring effects by various treatments