A host of factors regulating influenza virus replication.

A new series of genetic screens begins to illuminate the interaction between influenza virus and the infected cell

An Inhibitory Activity in Human Cells Restricts the Function of an Avian-like Influenza Virus Polymerase

SummaryTransmission of avian influenza virus into human populations has the potential to cause pandemic outbreaks. A major determinant of species tropism is the identity of amino acid 627 in the PB2 subunit of the heterotrimeric influenza polymerase; glutamic acid predominates in avian PB2, whereas lysine occupies this position in human isolates. We show that a dominant inhibitory activity in human cells potently and selectively restricts the function of polymerases containing an avian-like PB2 with glutamic acid at residue 627. Restricted polymerases fail to assemble into ribonucleoprotein complexes, resulting in decreased genome transcription, replication, and virus production without any significant effect on relative viral infectivity. Understanding the molecular basis of this species-specific restriction should provide strategies to prevent and treat avian influenza outbreaks in humans

The Plight of Modern Markets: How Universal Banking Undermines Capital Markets

© 2016 Banca Monte dei Paschi di Siena SpA This paper explains the process of competitive deregulation that led both the US and the UK to embrace universal banking and to abandon the functional separation of financial activities that had long characterized their financial systems. The paper argues that some of the consequences of favouring universal banking over functional separation that were understood in the 1930s were rarely voiced in years preceding deregulation. The principal argument offered in favour of separation was that the commercial banking system, which is supported by a government ‘safety net’, needs to be protected from the risks inherent in investment banking. By contrast, this paper argues that functional separation played an important role in protecting capital markets from the banking system. Universal banking is associated historically with thinly traded stock markets, and this paper argues that universal banking promotes the formation of a small group of large dealer-banks which dominate the financial system and whose interests are best served by trading on nonpublic over-the-counter (OTC) markets. The paper finds that just such a group played a key role in the growing importance of such OTC markets in the US over the past few decades. The paper then argues that the benefits of the greater liquidity that large universal banks can provide to capital markets are offset by the dangers they create when they err. Because mistakes at these large banks are often allowed to grow in size to match the size of the banks, they distort prices on financial markets and sometimes create systemic risk. Two recent examples are given: J.P. Morgan Chase Bank's ‘London whale’ fiasco and UBS, Merrill Lynch and Citibank's exposures to subprime mortgages. Finally, the paper explains that the Senate Report on the Glass–Steagall Act indicates that the Act was designed in part to limit commercial bank participation in the margin loan market, as this activity makes possible a feedback loop between increases in the money supply and increases in asset prices, which in turn can generate an asset price bubble in capital markets. The recent crisis has led modern researchers to rediscover the relationship between margin lending, feedback loops, and asset price bubbles that was well understood by at least some legislators in the 1930s. The paper argues that the recent crisis demonstrates that modern banking regulation needs to be informed by an understanding of the consequences that may arise when a financial system is dominated by universal banks

Changes in the V3 region of gp120 contribute to unusually broad coreceptor usage of an HIV-1 isolate from a CCR5 Delta32 heterozygote

AbstractHeterozygosity for the CCR5 Δ32 allele is associated with delayed progression to AIDS in human immunodeficiency virus type 1 (HIV-1) infection. Here we describe an unusual HIV-1 isolate from the blood of an asymptomatic individual who was heterozygous for the CCR5 Δ32 allele and had reduced levels of CCR5 expression. The primary virus used CCR5, CXCR4, and an unusually broad range of alternative coreceptors to enter transfected cells. However, only CXCR4 and CCR5 were used to enter primary T cells and monocyte-derived macrophages, respectively. Full-length Env clones had an unusually long V1/V2 region and rare amino acid variants in the V3 and C4 regions. Mutagenesis studies and structural models suggested that Y308, D321, and to a lesser extent K442 and E444, contribute to the broad coreceptor usage of these Envs, whereas I317 is likely to be a compensatory change. Furthermore, database analysis suggests that covariation can occur at positions 308/317 and 308/321 in vivo. Y308 and D321 reduced dependence on the extracellular loop 2 (ECL2) region of CCR5, while these residues along with Y330, K442, and E444 enhanced dependence on the CCR5 N-terminus compared to clade B consensus residues at these positions. These results suggest that expanded coreceptor usage of HIV-1 can occur in some individuals without rapid progression to AIDS as a consequence of changes in the V3 region that reduce dependence on the ECL2 region of CCR5 by enhancing interactions with conserved structural elements in G-protein-coupled receptors

Virology under the microscope—a call for rational discourse

Viruses have brought humanity many challenges: respiratory infection, cancer, neurological impairment and immunosuppression to name a few. Virology research over the last 60+ years has responded to reduce this disease burden with vaccines and antivirals. Despite this long history, the COVID-19 pandemic has brought unprecedented attention to the field of virology. Some of this attention is focused on concern about the safe conduct of research with human pathogens. A small but vocal group of individuals has seized upon these concerns – conflating legitimate questions about safely conducting virus-related research with uncertainties over the origins of SARS-CoV-2. The result has fueled public confusion and, in many instances, ill-informed condemnation of virology. With this article, we seek to promote a return to rational discourse. We explain the use of gain-of-function approaches in science, discuss the possible origins of SARS-CoV-2 and outline current regulatory structures that provide oversight for virological research in the United States. By offering our expertise, we – a broad group of working virologists – seek to aid policy makers in navigating these controversial issues. Balanced, evidence-based discourse is essential to addressing public concern while maintaining and expanding much-needed research in virology

Unusual Influenza A Viruses in Bats

Influenza A viruses infect a remarkably diverse number of hosts. Two completely new influenza A virus subtypes were recently discovered in bats, dramatically expanding the host range of the virus. These bat viruses are extremely divergent from all other known strains and likely have unique replication cycles. Phylogenetic analysis indicates long-term, isolated evolution in bats. This is supported by a high seroprevalence in sampled bat populations. As bats represent ~20% of all classified mammals, these findings suggests the presence of a massive cryptic reservoir of poorly characterized influenza A viruses. Here, we review the exciting progress made on understanding these newly discovered viruses, and discuss their zoonotic potential