Full genome ultra-deep pyrosequencing associates G-to-A hypermutation of the hepatitis B virus genome with the natural progression of hepatitis

SUMMARY. Human APOBEC3 (A3) cytosine deaminases are antiviral restriction factors capable of editing the genome the hepatitis B virus (HBV). Despite the importance of the human A3 protein family for the innate immune response little is known about the clinical relevance for hepatitis B. The aim of this study was to utilize ultra-deep pyrosequencing (UDPS) data to analyse the phenomenon of G-to-A hypermutation of the complete HBV genome and to relate it to fundamental characteristics of patients with chronic hepatitis B. By analysing the viral population of 80 treatment na€ ıve patients (47 HBeAg-positive and 33 HBeAg-negative), we identified an unequal distribution of G-to-A hypermutations across the genome. Our data indicate that G-to-A hypermutation occurs predominantly in a region between nucleotide positions 600 and 1800 a region which is usually single stranded in matured HBV particles. This implies that A3 likely edits HBV in the virion. Hypermutation rates for HBeAg-negative patients were more than 10-fold higher than those of HBeAg-positive patients. For HBeAg-negative patients higher hypermutation rates were significantly associated with the degree of fibrosis. Additionally, we found that for HBeAg-positive chronic hepatitis G-to-A hypermutation rates were significantly associated with the relative prevalence of the G1764A mutation, which is related to HBeAg seroconversion. In total, our data imply an important association of hypermutation mediated by A3 deaminases with the natural progression of chronic hepatitis B infections both in terms of HBeAg seroconversion and disease progression towards cirrhosis

Hepatitis {B} Virus Drug Resistance Tools: {One} Sequence, Two Predictions

Drug resistance testing, genotype analysis, and the determination of immune and vaccine escape variants support personalized antiviral treatment for hepatitis B patients. As phenotypic drug resistance testing for hepatitis B virus (HBV) is especially labor-intensive, due to the lack of simple cell culture systems, genotypic methods play a very pronounced role. The genetic structure of HBV allows the simultaneous analysis of two different genes by examination of a single region in the genome of HBV. Nevertheless, the overlapping open reading frames of the hepatitis B surface antigen (HBsAg) and the reverse transcriptase (RT) have to be interpreted separately. In diagnostic procedures, standard Sanger type sequencing (mostly performed as a dye-dideoxynucleotide terminator system) is still the most commonly used method. This allows using established techniques for interpreting those types of genetic information. Besides reviewing the foundation of drug resistance interpretation for HBV, different interpretation systems, either commercially available (TRUGENE, Abbott, ViroScore) or free to use (geno2pheno[HBV], HIV-GRADE HBV tool), are compared in this article. (C) 2014 S. Karger AG, Base

Häufigkeit von HBsAg (Hepatitis B surface-antigen) Mutationen in Isolaten resistenter Hepatitis B-Viren

The dorsal premotor cortex (dPMC) is a key region for motor learning and sensorimotor integration, yet we have limited understanding of its functional interactions with other regions. Previous work has started to examine functional connectivity in several brain areas using resting state functional connectivity (RSFC) and meta-analytical connectivity modelling (MACM). More recently, structural covariance (SC) has been proposed as a technique that may also allow delineation of functional connectivity. Here, we applied these three approaches to provide a comprehensive characterization of functional connectivity with a seed in the left dPMC that a previous meta-analysis of functional neuroimaging studies has identified as playing a key role in motor learning. Using data from two sources (the Rockland sample, containing resting state data and anatomical scans from 132 participants, and the BrainMap database, which contains peak activation foci from over 10,000 experiments), we conducted independent whole-brain functional connectivity mapping analyses of a dPMC seed. RSFC and MACM revealed similar connectivity maps spanning prefrontal, premotor, and parietal regions, while the SC map identified more widespread frontal regions. Analyses indicated a relatively consistent pattern of functional connectivity between RSFC and MACM that was distinct from that identified by SC. Notably, results indicate that the seed is functionally connected to areas involved in visuomotor control and executive functions, suggesting that the dPMC acts as an interface between motor control and cognition