The hepatitis delta virus (HDV) is distributed worldwide and related to the most severe form of viral hepatitis. HDV is a satellite RNA virus dependent on hepatitis B surface antigens to assemble its envelope and thus form new virions and propagate infection. HDV has a small 1.7 Kb genome making it the smallest known human virus. This deceivingly simple virus has unique biological features and many aspects of its life cycle remain elusive. The present review endeavors to gather the available information on HDV epidemiology and clinical features as well as HDV biology.

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The rate of infection by the GBV-C virus was investigated in a group of 214 individuals at high risk of infection with parenterally transmitted viruses, and all living in the Lisbon metropolitan area (Portugal). RNA was extracted from plasma samples, and a fragment of the 5'-UTR was amplified by RT-PCR, disclosing a high prevalence of infection (40.7%). Most probably due to similar modes of viral transmission, the majority of GBV-C (+) individuals were found to be coinfected with HIV and/or HCV. A genomic region covering part of the E1/E2 glycoprotein coding sequence was amplified from approximately half of the GBV-C positive samples (44/87). Phylogenetic analysis of nucleotide sequences showed segregation of Portuguese GBV-C strains with genotype 1 (G1, n = 10) and genotype 2 (G2, n = 24) references. Genotype 1 was significantly associated with the African descent of those infected. Curiously, some of the strains assigned to genotype 2 were shown to form a separate cluster (designated G2*) in both neighbor-joining and Bayesian phylogenetic trees, which was confirmed by multivariate principal coordinate analysis. However, analysis of the distribution of intra- and intergenotype genetic distances support the hypothesis that rather than corresponding to a new viral genotype, G2* is a geographical subcluster within the genotype 2 radiation. J. Med. Virol. 82:452-459, 2010. (c) 2010 Wiley-Liss, Inc.

Hepatitis delta virus (HDV) is the agent responsible for the most severe form of human viral hepatitis. The HDV genome consists of a single‐stranded circular RNA molecule that encodes for one single protein, the delta antigen. Given its simplicity, HDV must make use of several host cellular proteins to accomplish its life cycle processes, including transcription, replication, post‐transcriptional, and post‐translational modifications. Consequently, identification of the interactions established between HDV components and host proteins assumes a pivotal interest in the search of novel therapeutic targets. Here, we used the yeast three‐hybrid system to screen a human liver cDNA library to identify host proteins that interact with the HDV genomic RNA. One of the identified proteins corresponded to the splicing factor SF3B155, a component of the U2snRNP complex that is essential for the early recognition of 3′ splice sites in the pre‐mRNAs of human genes. We show that the interaction between the HDV genomic RNA and SF3B155 occurs in vivo and that the expression of HDV promotes changes in splicing of human genes whose alternative splicing is SF3B155‐dependent. We further show that expression of HDV triggers alterations in several constitutive and alternative splicing events in the tumor suppressor RBM5 transcript, with consequent reduction of its protein levels. This is the first description that HDV expression promotes changes in the splicing of human genes, and we suggest that the HDV‐induced alternative splicing changes, through SF3B155 sequester, may contribute for the early progression to hepatocellular carcinoma characteristic of HDV‐infected patients.

Entre os dias 13 e 17 de março de 2019, realizou-se um "encontro de visões de vários lados", tomando as palavras de Ailton Krenak, a Mostra Ameríndia – Indigenous Cinema Routes in Brazil, no auditório da Coleção Moderna do Museu Calouste Gulbenkian, em Lisboa.