APOBEC3G-induced hypermutation of human immunodeficiency virus type-1 is typically a discrete "all or nothing" phenomenon.

The rapid evolution of Human Immunodeficiency Virus (HIV-1) allows studies of ongoing host-pathogen interactions. One key selective host factor is APOBEC3G (hA3G) that can cause extensive and inactivating Guanosine-to-Adenosine (G-to-A) mutation on HIV plus-strand DNA (termed hypermutation). HIV can inhibit this innate anti-viral defense through binding of the viral protein Vif to hA3G, but binding efficiency varies and hypermutation frequencies fluctuate in patients.

Conserved footprints of APOBEC3G on Hypermutated human immunodeficiency virus type 1 and human endogenous retrovirus HERV-K(HML2) sequences.

The human polynucleotide cytidine deaminases APOBEC3G (hA3G) and APOBEC3F (hA3F) are antiviral restriction factors capable of inducing extensive plus-strand guanine-to-adenine (G-to-A) hypermutation in a variety of retroviruses and retroelements, including human immunodeficiency virus type 1 (HIV-1). They differ in target specificity, favoring plus-strand 5'GG and 5'GA dinucleotide motifs, respectively. To characterize their mutational preferences in detail, we analyzed single-copy, near-full-length HIV-1 proviruses which had been hypermutated in vitro by hA3G or hA3F.

Antiviral protein APOBEC3G localizes to ribonucleoprotein complexes found in P bodies and stress granules.

Members of the APOBEC (apolipoprotein B mRNA-editing enzyme catalytic polypeptide 1-like) family of cytidine deaminases inhibit host cell genome invasion by exogenous retroviruses and endogenous retrotransposons. Because these enzymes can edit DNA or RNA and potentially mutate cellular targets, their activities are presumably regulated; for instance, APOBEC3G (A3G) recruitment into high-molecular-weight ribonucleoprotein (RNP) complexes has been shown to suppress its enzymatic activity. We used tandem affinity purification together with mass spectrometry (MS) to identify protein components within A3G-containing RNPs.

HIV interaction with endosomes in macrophages and dendritic cells.

The human immunodeficiency virus type 1 (HIV-1) is an enveloped retrovirus that undergoes assembly at specific sites in infected cells. In macrophages, at least, this assembly occurs primarily on a subset of endocytic organelles that contain some of the markers found in late endosomes or multivesicular bodies (MVBs), in particular CD63. The budding of virus particles into endosomes has many features in common with the formation of exosomes and some limited biochemical comparison of HIV-1 particles produced from macrophages with exosomes suggests that the two have similar cellular origins.

Infectious HIV-1 assembles in late endosomes in primary macrophages.

Although human immunodeficiency virus type 1 (HIV-1) is generally thought to assemble at the plasma membrane of infected cells, virions have been observed in intracellular compartments in macrophages. Here, we investigated virus assembly in HIV-1-infected primary human monocyte-derived macrophages (MDM). Electron microscopy of cryosections showed virus particles, identified by their morphology and positive labeling with antibodies to the viral p17, p24, and envelope proteins, in intracellular vacuoles.

Remission, recovery, relapse, and recurrence in eating disorders: conceptualization and illustration of a validation strategy.

In a consensus-building process a group of experts from 19 European countries (COST Action B6) adapted the terms partial and full remission, relapse, recovery, and recurrence according to principles described by Frank et al. for depression. The empirical validity of the operationalizations was illustrated by longitudinal data on the post treatment course of 233 anorectic and 422 bulimic patients (diagnosed according to DSM-IIIR) from the German Project TR-EAT.

Inhibition of release of lentivirus particles with incorporated human influenza virus haemagglutinin by binding to sialic acid-containing cellular receptors.

Mutants of the haemagglutinin (HA) gene of human influenza virus A/Aichi/2/68 (H3N2) encoding HA proteins that are proteolytically cleaved intracellularly, defective in binding to cellular receptors or defective for acylation within the cytoplasmic C terminus have been generated. Here, the properties of these mutated HA molecules are described and their incorporation into the lipid membrane of released human immunodeficiency virus (HIV)-like particles is analysed. It is demonstrated that, when produced from cells coexpressing any of the binding-competent Aichi-HA molecules, release of HIV-like particles into the extracellular medium is reduced and the particles that are released fail to incorporate Aichi-HA.