These data reveal a new paradigm for carcinogenesis, in which colibactin-induced senescence has an important role.

Gene expression of DNA viruses requires nuclear import of the viral genome. Human Adenoviruses (Ads), like most DNA viruses, encode factors within early transcription units promoting their own gene expression and counteracting cellular antiviral defense mechanisms. The cellular transcriptional repressor Daxx prevents viral gene expression through the assembly of repressive chromatin remodeling complexes targeting incoming viral genomes. However, it has remained unclear how initial transcriptional activation of the adenoviral genome is achieved. Here we show that Daxx mediated repression of the immediate early Ad E1A promoter is efficiently counteracted by the capsid protein VI. This requires a conserved PPxY motif in protein VI. Capsid proteins from other DNA viruses were also shown to activate the Ad E1A promoter independent of Ad gene expression and support virus replication. Our results show how Ad entry is connected to transcriptional activation of their genome in the nucleus. Our data further suggest a common principle for genome activation of DNA viruses by counteracting Daxx related repressive mechanisms through virion proteins.

Bromodomain and extraterminal domain protein inhibitors (BETi) hold great promise as a novel class of cancer therapeutics. Because acquired resistance typically limits durable responses to targeted therapies, it is important to understand mechanisms by which tumor cells adapt to BETi. Here, through pooled shRNA screening of colorectal cancer cells, we identified tripartite motif-containing protein 33 (TRIM33) as a factor promoting sensitivity to BETi. We demonstrate that loss of TRIM33 reprograms cancer cells to a more resistant state through at least two mechanisms. TRIM33 silencing attenuates down-regulation of MYC in response to BETi. Moreover, loss of TRIM33 enhances TGF-β receptor expression and signaling, and blocking TGF-β receptor activity potentiates the antiproliferative effect of BETi. These results describe a mechanism for BETi resistance and suggest that combining inhibition of TGF-β signaling with BET bromodomain inhibition may offer new therapeutic benefits.bromodomain inhibitor | TRIM33 | JQ1 | drug resistance | TGF-β

Nuclear delivery of the adenoviral genome requires that the capsid cross the limiting membrane of the endocytic compartment and traverse the cytosol to reach the nucleus. This endosomal escape is initiated upon internalization and involves a highly coordinated process of partial disassembly of the entering capsid to release the membrane lytic internal capsid protein VI. Using wild-type and protein VI-mutated human adenovirus serotype 5 (HAdV-C5), we show that capsid stability and membrane rupture are major determinants of entry-related sorting of incoming adenovirus virions. Furthermore, by using electron cryomicroscopy, as well as penton-and protein VI-specific antibodies, we show that the amphipathic helix of protein VI contributes to capsid stability by preventing premature disassembly and deployment of pentons and protein VI. Thus, the helix has a dual function in maintaining the metastable state of the capsid by preventing premature disassembly and mediating efficient membrane lysis to evade lysosomal targeting. Based on these findings and structural data from cryo-electron microscopy, we suggest a refined disassembly mechanism upon entry. IMPORTANCEIn this study, we show the intricate connection of adenovirus particle stability and the entry-dependent release of the membrane-lytic capsid protein VI required for endosomal escape. We show that the amphipathic helix of the adenovirus internal protein VI is required to stabilize pentons in the particle while coinciding with penton release upon entry and that release of protein VI mediates membrane lysis, thereby preventing lysosomal sorting. We suggest that this dual functionality of protein VI ensures an optimal disassembly process by balancing the metastable state of the mature adenovirus particle.A denoviruses (AdVs) are nonenveloped, double-stranded DNA viruses that assemble in the nuclei of productively infected cells and are released at the end of the infection cycle into the extracellular milieu. Productive infection of new cells requires that the capsid follow a stepwise disassembly process upon entry that, if perfectly executed, results in highly efficient genome transfer to the nucleus (1, 2).The AdV virion is composed of 13 different polypeptides that form an icosahedral capsid encompassing the genome-containing viral core. The capsid is mainly composed of trimeric hexons building up the facets of the capsid. Pentons and fibers are located at each of the 12 vertices, where they form a pentameric penton base from which the trimeric fiber molecule elongates (3-5). In addition the capsid is stabilized via the cement proteins IIIa, VI, VIII, and IX. The capsid encloses the viral core, with the viral genome organized into chromatin through association with the major core protein VII and proteins V, X, TP, and IVa2 (3-5). Following (or concomitant with) capsid assembly, several of the virion proteins undergo proteolytic processing by the virion-incorporated adenoviral proteinase (AVP) (6). This process of virus maturation is essential to render ne...

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Background Limited data are available in Honduras describing the etiology and seasonality of respiratory infections, especially in rural outpatient settings. Better data may lead to improved therapeutic and preventative strategies. The goal of our study was to determine the viral etiology and seasonality of acute respiratory infections in a rural Honduran population of children. Methods Prospective clinic surveillance was conducted to identify children <5 years of age presenting with respiratory symptoms <5 days duration. We obtained data on age, sex, medical history, breastfeeding history, symptoms, risk factors, house hold setting, temperature, respiratory rate, and chest exam findings. To assess the association between specific viruses and weather, regional meteorological data were collected. Nasopharyngeal samples were tested for 16 respiratory viruses using a multiplex PCR panel. Results From February 2010 through June 2011, 345 children <5 years of age were enrolled; 17%, 23%, 30%, and 31% were <6, 6–11, 12–23, and 24–60 months old, respectively. Including all clinics in the region, 44.5% of patients <5 years of age with documented respiratory diagnoses were enrolled. At least one virus was identified in 75.4% children, of which 7.5% were co-infections; 13.3% were positive for parainfluenza, 11.9% for influenza, 8.1% for human metapneumovirus (hMPV), and 7.5% for respiratory syncytial virus (RSV). Rainfall correlated with parainfluenza (p≤0.0001), influenza (p≤0.0001), hMPV (p= 0.0182), and RSV (p≤0.0001). Conclusions These results suggest that the spectrum of viruses in ill rural Honduran children is similar to that in North and Central America, though the seasonality is typical of some tropical regions.

Summary Imaging host-pathogen interactions in real time can provide significant insight into dynamic processes and provide information about time and space of their occurences. Here we present detailed experimental instructions on how to image the membrane penetration process of the non-enveloped adenovirus in rel time. The system is based on a cell line stably expressing the lectin galectin-3 fused to a fluorophore. Membrane-lytic events during adenovirus cell entry can be monitored by the recruitment of galectin-3 to galactose-containing membrane glycoproteins on the exo-surface of ruptured membranes. The simultaneous use of fluorescently labeled adenoviral capsids allows to image the events in unmatched temporal resolution.

Limited data are available in rural Honduran settings describing the etiology of respiratory infections, partially due to limited specimen transport. A new molecular transport media (MTM) preserves released nucleic acid at ambient temperature for later detection. Prospective surveillance was conducted in a Honduran clinic to identify 233 children less than 5 years of age presenting with respiratory symptoms. We obtained two nasopharyngeal samples and stored one in PrimeStore® MTM at room temperature and one in universal transport media (UTM) at -80° Celsius. The specimens were then transported to Cincinnati Children’s Hospital and tested for 16 respiratory viruses using a multiplex PCR panel. The two specimen collection systems were similar for detecting the four most common viruses: influenza (Kappa=0.7676, p<0.0001), human metapneumovirus (Kappa=0.8770, p<0.0001), respiratory syncytial virus (Kappa=0.6849, p<0.0001), and parainfluenza (Kappa=0.8796, p<0.0001). These results suggest that clinical specimens transported via PrimeStore® MTM and UTM yield similar viral multiplex PCR results.