Thermodynamic coupling of the tandem RRM domains of hnRNP A1 underlie its pleiotropic RNA binding functions.

The functional properties of RNA binding proteins (RBPs) require allosteric regulation through interdomain communication. Despite the importance of allostery to biological regulation, only a few studies have been conducted to describe the biophysical nature by which interdomain communication manifests in RBPs. Here, we show for hnRNP A1 that interdomain communication is vital for the unique stability of its amino-terminal domain, which consists of two RNA recognition motifs (RRMs).

Enterovirus evolution reveals the mechanism of an RNA-targeted antiviral and determinants of viral replication.

Selective pressures on viruses provide opportunities to establish target site specificity and mechanisms of antivirals. Enterovirus (EV)-A71 with resistant mutations in the stem loop (SL) II internal ribosome entry site (IRES) (SLII) were selected at low doses of the antiviral dimethylamiloride (DMA)-135. The EV-A71 mutants were resistant to DMA-135 at concentrations that inhibit replication of wild-type virus.

The Repurposing of Cellular Proteins during Enterovirus A71 Infection.

Viruses pose a great threat to people's lives. Enterovirus A71 (EV-A71) infects children and infants all over the world with no FDA-approved treatment to date. Understanding the basic mechanisms of viral processes aids in selecting more efficient drug targets and designing more effective antivirals to thwart this virus.

Thermodynamic Coupling of the tandem RRM domains of hnRNP A1 underlie its Pleiotropic RNA Binding Functions.

The functional properties of RNA-binding proteins (RBPs) require allosteric regulation through inter-domain communication. Despite the foundational importance of allostery to biological regulation, almost no studies have been conducted to describe the biophysical nature by which inter-domain communication manifests in RBPs. Here, we show through high-pressure studies with hnRNP A1 that inter-domain communication is vital for the unique stability of its N- terminal domain containing a tandem of RNA Recognition Motifs (RRMs).

Juneteenth in STEMM and the barriers to equitable science.

We are 52 Black scientists. Here, we establish the context of Juneteenth in STEMM and discuss the barriers Black scientists face, the struggles they endure, and the lack of recognition they receive. We review racism's history in science and provide institutional-level solutions to reduce the burdens on Black scientists.

Influenza virus mRNAs encode determinants for nuclear export via the cellular TREX-2 complex.

Nuclear export of influenza A virus (IAV) mRNAs occurs through the nuclear pore complex (NPC). Using the Auxin-Induced Degron (AID) system to rapidly degrade proteins, we show that among the nucleoporins localized at the nucleoplasmic side of the NPC, TPR is the key nucleoporin required for nuclear export of influenza virus mRNAs. TPR recruits the TRanscription and EXport complex (TREX)-2 to the NPC for exporting a subset of cellular mRNAs.

Medicaid coverage and access to obstetrics and gynecology subspecialists: findings from a national mystery caller study in the United States.

Background: Previous research suggests that access to healthcare may influence the diagnosis and treatment of obstetrical and gynecologic pathologies. Audit studies, a single-blinded and patient-centered design, have been employed to measure access to care for health services. To date, no study has assessed the dimensions of access to obstetrics and gynecologic subspecialty care based on insurance type (Medicaid vs commercial).

Biophysical Analysis of Small Molecule Binding to Viral RNA Structures.

RNA molecules are essential for carrying genetic information and regulating gene expression in most organisms including human pathogenic RNA and relate retro viruses. Targeting viral RNA (vRNA) structures provide broad opportunities to develop chemical tools to probe molecular virology and to discover novel targets for therapeutic intervention. An increasing number of RNA binding small molecules are being identified, stimulating increased interests in small molecule drug discovery for RNA targets.

Alternatively spliced CSF3R isoforms in SRSF2 P95H mutated myeloid neoplasms.

Alternatively spliced colony stimulating factor 3 receptor (CSF3R) isoforms Class III and Class IV are observed in myelodysplastic syndromes (MDS), but their roles in disease remain unclear. We report that the MDS-associated splicing factor SRSF2 affects the expression of Class III and Class IV isoforms and perturbs granulopoiesis. Add-back of the Class IV isoform in Csf3r-null mouse progenitor cells increased granulocyte progenitors with impaired neutrophil differentiation, while add-back of the Class III produced dysmorphic neutrophils in fewer numbers.

Encoded Conformational Dynamics of the HIV Splice Site A3 Regulatory Locus: Implications for Differential Binding of hnRNP Splicing Auxiliary Factors.

Alternative splicing of the HIV transcriptome is controlled through cis regulatory elements functioning as enhancers or silencers depending on their context and the type of host RNA binding proteins they recruit. Splice site acceptor A3 (ssA3) is one of the least used acceptor sites in the HIV transcriptome and its activity determines the levels of tat mRNA. Splice acceptor 3 is regulated by a combination of cis regulatory sequences, auxiliary splicing factors, and presumably RNA structure.

R-BIND 2.0: An Updated Database of Bioactive RNA-Targeting Small Molecules and Associated RNA Secondary Structures.

Discoveries of RNA roles in cellular physiology and pathology are increasing the need for new tools that modulate the structure and function of these biomolecules, and small molecules are proving useful. In 2017, we curated the NA-targeted oactive ligad atabase (R-BIND) and discovered distinguishing physicochemical properties of RNA-targeting ligands, leading us to propose the existence of an "RNA-privileged" chemical space. Biennial updates of the database and the establishment of a website platform (rbind.

Amilorides inhibit SARS-CoV-2 replication in vitro by targeting RNA structures.

The SARS-CoV-2 pandemic, and the likelihood of future coronavirus pandemics, emphasized the urgent need for development of novel antivirals. Small-molecule chemical probes offer both to reveal aspects of virus replication and to serve as leads for antiviral therapeutic development. Here, we report on the identification of amiloride-based small molecules that potently inhibit OC43 and SARS-CoV-2 replication through targeting of conserved structured elements within the viral 5′-end.

A Structurally Conserved RNA Element within SARS-CoV-2 ORF1a RNA and S mRNA Regulates Translation in Response to Viral S Protein-Induced Signaling in Human Lung Cells.

The positive-sense, single-stranded RNA genome SARS-CoV-2 harbors functionally important -acting elements governing critical aspects of viral gene expression. However, insights on how these elements sense various signals from the host cell and regulate viral protein synthesis are lacking. Here, we identified two novel -regulatory elements in SARS-CoV-2 ORF1a and S RNAs and describe their role in translational control of SARS-CoV-2.

HnRNP A1/A2 Proteins Assemble onto 7SK snRNA via Context Dependent Interactions.

7SK small nuclear RNA (snRNA) is an abundant and ubiquitously expressed noncoding RNA that functions to modulate the activity of RNA Polymerase II (RNAPII) in part by stabilizing distinct pools of 7SK-protein complexes. Prevailing models suggest that the secondary structure of 7SK is dynamically remodeled within its alternative RNA-protein pools such that its architecture differentially regulates the exchange of cognate binding partners. The nuclear hnRNP A1/A2 proteins influence the biology of 7SK snRNA via processes that require an intact stem loop (SL) 3 domain; however, the molecular details by which hnRNPs assemble onto 7SK snRNA are yet to be described.

Enterovirus A71 Vaccines.

Enterovirus A71 (EV-A71) is a major causative agent of hand, foot, and mouth disease (HFMD) and herpangina. Moreover, EV-A71 infection can lead to neurological complications and death. Vaccination is the most efficient way to control virus infection.

Thermodynamic stability of hnRNP A1 low complexity domain revealed by high-pressure NMR.

We have investigated the pressure- and temperature-induced conformational changes associated with the low complexity domain of hnRNP A1, an RNA-binding protein able to phase separate in response to cellular stress. Solution NMR spectra of the hnRNP A1 low-complexity domain fused with protein-G B1 domain were collected from 1 to 2500 bar and from 268 to 290 K. While the GB1 domain shows the typical pressure-induced and cold temperature-induced unfolding expected for small globular domains, the low-complexity domain of hnRNP A1 exhibits unusual pressure and temperature dependences.

Amilorides inhibit SARS-CoV-2 replication in vitro by targeting RNA structures.

The SARS-CoV-2 pandemic, and the likelihood of future coronavirus pandemics, has rendered our understanding of coronavirus biology more essential than ever. Small molecule chemical probes offer to both reveal novel aspects of virus replication and to serve as leads for antiviral therapeutic development. The RNA-biased amiloride scaffold was recently tuned to target a viral RNA structure critical for translation in enterovirus 71, ultimately uncovering a novel mechanism to modulate positive-sense RNA viral translation and replication.

Secondary structure determination of conserved SARS-CoV-2 RNA elements by NMR spectroscopy.

The current pandemic situation caused by the Betacoronavirus SARS-CoV-2 (SCoV2) highlights the need for coordinated research to combat COVID-19. A particularly important aspect is the development of medication. In addition to viral proteins, structured RNA elements represent a potent alternative as drug targets.

IRES-targeting small molecule inhibits enterovirus 71 replication via allosteric stabilization of a ternary complex.

Enterovirus 71 (EV71) poses serious threats to human health, particularly in Southeast Asia, and no drugs or vaccines are available. Previous work identified the stem loop II structure of the EV71 internal ribosomal entry site as vital to viral translation and a potential target. After screening an RNA-biased library using a peptide-displacement assay, we identify DMA-135 as a dose-dependent inhibitor of viral translation and replication with no significant toxicity in cell-based studies.

Integrated approaches to reveal mechanisms by which RNA viruses reprogram the cellular environment.

RNA viruses are major threats to global society and mass outbreaks can cause long-lasting damage to international economies. RNA and related retro viruses represent a large and diverse family that contribute to the onset of human diseases such as AIDS; certain cancers like T cell lymphoma; severe acute respiratory illnesses as seen with COVID-19; and others. The hallmark of this viral family is the storage of genetic material in the form of RNA, and upon infecting host cells, their RNA genomes reprogram the cellular environment to favor productive viral replication.