From a genome-wide screen of RNAi molecules against SARS-CoV-2 to a validated broad-spectrum and potent prophylaxis.

Expanding the arsenal of prophylactic approaches against SARS-CoV-2 is of utmost importance, specifically those strategies that are resistant to antigenic drift in Spike. Here, we conducted a screen of over 16,000 RNAi triggers against the SARS-CoV-2 genome, using a massively parallel assay to identify hyper-potent siRNAs. We selected Ten candidates for in vitro validation and found five siRNAs that exhibited hyper-potent activity (IC50 < 20 pM) and strong blockade of infectivity in live-virus experiments.

A protease-activatable luminescent biosensor and reporter cell line for authentic SARS-CoV-2 infection.

Efforts to define serological correlates of protection against COVID-19 have been hampered by the lack of a simple, scalable, standardised assay for SARS-CoV-2 infection and antibody neutralisation. Plaque assays remain the gold standard, but are impractical for high-throughput screening. In this study, we show that expression of viral proteases may be used to quantitate infected cells.

The SMC5/6 complex compacts and silences unintegrated HIV-1 DNA and is antagonized by Vpr.

Silencing of nuclear DNA is an essential feature of innate immune responses to invading pathogens. Early in infection, unintegrated lentiviral cDNA accumulates in the nucleus yet remains poorly expressed. In HIV-1-like lentiviruses, the Vpr accessory protein enhances unintegrated viral DNA expression, suggesting Vpr antagonizes cellular restriction.

Antagonism of PP2A is an independent and conserved function of HIV-1 Vif and causes cell cycle arrest.

The seminal description of the cellular restriction factor APOBEC3G and its antagonism by HIV-1 Vif has underpinned two decades of research on the host-virus interaction. We recently reported that HIV-1 Vif is also able to degrade the PPP2R5 family of regulatory subunits of key cellular phosphatase PP2A (PPP2R5A-E; Greenwood et al., 2016; Naamati et al.

Promiscuous Targeting of Cellular Proteins by Vpr Drives Systems-Level Proteomic Remodeling in HIV-1 Infection.

HIV-1 encodes four "accessory proteins" (Vif, Vpr, Vpu, and Nef), dispensable for viral replication in vitro but essential for viral pathogenesis in vivo. Well characterized cellular targets have been associated with Vif, Vpu, and Nef, which counteract host restriction and promote viral replication. Conversely, although several substrates of Vpr have been described, their biological significance remains unclear.

Functional proteomic atlas of HIV infection in primary human CD4+ T cells.

Viruses manipulate host cells to enhance their replication, and the identification of cellular factors targeted by viruses has led to key insights into both viral pathogenesis and cell biology. In this study, we develop an HIV reporter virus (HIV-AFMACS) displaying a streptavidin-binding affinity tag at the surface of infected cells, allowing facile one-step selection with streptavidin-conjugated magnetic beads. We use this system to obtain pure populations of HIV-infected primary human CD4+ T cells for detailed proteomic analysis, and quantitate approximately 9000 proteins across multiple donors on a dynamic background of T cell activation.

Human Fumarate Hydratase Is Dual Localized by an Alternative Transcription Initiation Mechanism.

Fumarate hydratase (FH, fumarase), is a tricarboxylic acid cycle enzyme localized in the mitochondrial matrix. However, a common theme, conserved from yeast to human, is the existence of a large cytosolic population of FH. FH has been shown to function as a tumor suppressor gene and is now implicated in various diseases.

Dual-targeted proteins tend to be more evolutionarily conserved.

In eukaryotic cells, identical proteins can be located in more than a single subcellular compartment, a phenomenon termed dual targeting. We hypothesized that dual-targeted proteins should be more evolutionary conserved than exclusive mitochondrial proteins, due to separate selective pressures administered by the different compartments to maintain the functions associated with the protein sequences. We employed codon usage bias, propensity for gene loss, phylogenetic relationships, conservation analysis at the DNA level, and gene expression, to test our hypothesis.

Fumarase: a paradigm of dual targeting and dual localized functions.

The enzyme fumarase is a conserved protein in all organisms with regard to its sequence, structure and function. This enzyme participates in the tricarboxylic acid cycle in mitochondria which is essential for cellular respiration in eukaryotes. However, a common theme conserved from yeast to humans is the existence of a cytosolic form of fumarase; hence this protein is dual localized.

Infantile cerebral and cerebellar atrophy is associated with a mutation in the MED17 subunit of the transcription preinitiation mediator complex.

Primary microcephaly of postnatal onset is a feature of many neurological disorders, mostly associated with mental retardation, seizures, and spasticity, and it typically carries a grave prognosis. Five infants from four unrelated families of Caucasus Jewish origin presented soon after birth with spasticity, epilepsy, and profound psychomotor retardation. Head circumference percentiles declined, and brain MRI disclosed marked cereberal and cerebellar atrophy with severe myelination defect.

Dual targeting of Nfs1 and discovery of its novel processing enzyme, Icp55.

In eukaryotes, each subcellular compartment harbors a specific group of proteins that must accomplish specific tasks. Nfs1 is a highly conserved mitochondrial cysteine desulfurase that participates in iron-sulfur cluster assembly as a sulfur donor. Previous genetic studies, in Saccharomyces cerevisiae, have suggested that this protein distributes between the mitochondria and the nucleus with biochemically undetectable amounts in the nucleus (termed "eclipsed distribution").