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Human cytomegalovirus (HCMV) represents the viral leading cause of congenital birth defects and uses the gH/gL/UL128-130-131A complex (Pentamer) to enter different cell types, including epithelial and endothelial cells. Upon infection, Pentamer elicits the most potent neutralizing response against HCMV, representing a key vaccine candidate. Despite its relevance, the structural basis for Pentamer receptor recognition and antibody neutralization is largely unknown. Here, we determine the structures of Pentamer bound to neuropilin 2 (NRP2) and a set of potent neutralizing antibodies against HCMV. Moreover, we identify thrombomodulin (THBD) as a functional HCMV receptor and determine the structures of the Pentamer-THBD complex. Unexpectedly, both NRP2 and THBD also promote dimerization of Pentamer. Our results provide a framework for understanding HCMV receptor engagement, cell entry, antibody neutralization, and outline strategies for antiviral therapies against HCMV.

Clustering for the kill Cluster of differentiation 20 (CD20) is a membrane protein that defines most B cell populations and is the target of therapeutic antibodies to treat malignancies and autoimmune disorders. Rougé et al. present the structure of CD20 bound to the antibody rituximab that activates the complement system to kill B cells. CD20 forms a dimer and each monomer binds one rituximab antigen-binding fragment (Fab) to give 2:2 stoichiometry. The compact packing between Fab arms and CD20 gives rise to circular assemblies with a diameter similar to that of antibody hexamers known to recruit the first component of the complement cascade. Science , this issue p. 1224

The expression analysis of recombinant proteins is a challenging step in any high-throughput protein production pipeline. Often multiple expression systems and a variety of expression construct designs are considered for the production of a protein of interest. There is a strong need to triage constructs rapidly and systematically. This chapter describes a semiautomated method for the simultaneous purification and characterization of proteins expressed from multiple samples of expression cultures from the E. coli, baculovirus expression vector system, and mammalian transient expression systems. This method assists in the selection of the most promising expression construct(s) or the most favorable expression condition(s) to move forward into large-scale protein production.

There is increased concern with the development of resistance to insecticidal proteins currently expressed in crop plants, especially against high-resistance-risk pests such as fall armyworm (FAW), Spodoptera frugiperda, a maize pest that already has developed resistance to Bacillus thuringiensis (Bt) proteins such as Cry1F. Lepidopteran-specific proteins that bind new insect receptors will be critical in managing current Cry1F-resistant FAW and delaying future resistance development. Results from resistant insect assays, disabled insecticidal protein (DIP) bioassays, and cell-based assays using insect cells expressing individual receptors demonstrate that target receptors of the Cry1Da_7 and Cry1B.868 proteins are different from each other and from those of commercially available Bt proteins such as Cry1F, Cry1A.105, Cry2Ab, and Vip3A. Therefore, pyramiding these two new proteins in maize will provide durable control of this economically important pest in production agriculture., Two new modified Bacillus thuringiensis (Bt) proteins, Cry1Da_7 and Cry1B.868, with activity against fall armyworms (FAW), Spodoptera frugiperda (J.E. Smith), were evaluated for their potential to bind new insect receptors compared to proteins currently deployed as plant-incorporated protectants (PIPs) in row crops. Results from resistant insect bioassays, disabled insecticidal protein (DIP) bioassays, and cell-based assays using insect cells expressing individual receptors demonstrate that receptor utilizations of the newly modified Cry1Da_7 and Cry1B.868 proteins are distinct from each other and from those of commercially available Bt proteins such as Cry1F, Cry1A.105, Cry2Ab, and Vip3A. Accordingly, these two proteins target different insect proteins in FAW midgut cells and when pyramided together should provide durability in the field against this economically important pest. IMPORTANCE There is increased concern with the development of resistance to insecticidal proteins currently expressed in crop plants, especially against high-resistance-risk pests such as fall armyworm (FAW), Spodoptera frugiperda, a maize pest that already has developed resistance to Bacillus thuringiensis (Bt) proteins such as Cry1F. Lepidopteran-specific proteins that bind new insect receptors will be critical in managing current Cry1F-resistant FAW and delaying future resistance development. Results from resistant insect assays, disabled insecticidal protein (DIP) bioassays, and cell-based assays using insect cells expressing individual receptors demonstrate that target receptors of the Cry1Da_7 and Cry1B.868 proteins are different from each other and from those of commercially available Bt proteins such as Cry1F, Cry1A.105, Cry2Ab, and Vip3A. Therefore, pyramiding these two new proteins in maize will provide durable control of this economically important pest in production agriculture.

Human cytomegalovirus (HCMV) infects the majority of the human population and represents the leading viral cause of congenital birth defects. HCMV utilizes the glycoproteins gHgLgO (Trimer) to bind to platelet-derived growth factor receptor alpha (PDGFRα) and transforming growth factor beta receptor 3 (TGFβR3) to gain entry into multiple cell types. This complex is targeted by potent neutralizing antibodies and represents an important candidate for therapeutics against HCMV. Here, we determine three cryogenic electron microscopy (cryo-EM) structures of the trimer and the details of its interactions with four binding partners: the receptor proteins PDGFRα and TGFβR3 as well as two broadly neutralizing antibodies. Trimer binding to PDGFRα and TGFβR3 is mutually exclusive, suggesting that they function as independent entry receptors. In addition, Trimer-PDGFRα interaction has an inhibitory effect on PDGFRα signaling. Our results provide a framework for understanding HCMV receptor engagement, neutralization, and the development of anti-viral strategies against HCMV.

The expression analysis of recombinant proteins is a challenging step in any high-throughput protein production pipeline. Often multiple expression systems and a variety of expression construct designs are considered for the production of a protein of interest. There is a strong need to triage constructs rapidly and systematically. This chapter describes a semiautomated method for the simultaneous purification and characterization of proteins expressed from multiple samples of expression cultures from the E. coli, baculovirus expression vector system, and mammalian transient expression systems. This method assists in the selection of the most promising expression construct(s) or the most favorable expression condition(s) to move forward into large-scale protein production.

Plant LOSS OF GDU 2 (LOG2) and Mammalian Mahogunin Ring Finger 1 (MGRN1) proteins are RING-type E3 ligases sharing similarity N-terminal to the RING domain. Deletion of this region disrupts the interaction of LOG2 with the plant membrane protein GLUTAMINE DUMPER1 (GDU1). Phylogenetic analysis identified two clades of LOG2/MGRN1-like proteins in vertebrates and plants. The ability of MGRN1 to functionally replace LOG2 was tested. MGRN1 ubiquitylates GDU1 in vitro and can partially substitute for LOG2 in the plant, partially restoring amino acid resistance to a GDU1-myc over-expression, log2-2 background. Altogether, these results suggest a conserved function for the N-terminal domain in evolution.

Amino acids serve as transport forms for organic nitrogen in the plant, and multiple transport steps are involved in cellular import and export. While the nature of the export mechanism is unknown, overexpression of GLUTAMINE DUMPER1 (GDU1) in Arabidopsis (Arabidopsis thaliana) led to increased amino acid export. To gain insight into GDU1’s role, we searched for ethyl-methanesulfonate suppressor mutants and performed yeast-two-hybrid screens. Both methods uncovered the same gene, LOSS OF GDU2 (LOG2), which encodes a RING-type E3 ubiquitin ligase. The interaction between LOG2 and GDU1 was confirmed by glutathione S-transferase pull-down, in vitro ubiquitination, and in planta coimmunoprecipitation experiments. Confocal microscopy and subcellular fractionation indicated that LOG2 and GDU1 both localized to membranes and were enriched at the plasma membrane. LOG2 expression overlapped with GDU1 in the xylem and phloem tissues of Arabidopsis. The GDU1 protein encoded by the previously characterized intragenic suppressor mutant log1-1, with an arginine in place of a conserved glycine, failed to interact in the multiple assays, suggesting that the Gdu1D phenotype requires the interaction of GDU1 with LOG2. This hypothesis was supported by suppression of the Gdu1D phenotype after reduction of LOG2 expression using either artificial microRNAs or a LOG2 T-DNA insertion. Altogether, in accordance with the emerging bulk of data showing membrane protein regulation via ubiquitination, these data suggest that the interaction of GDU1 and the ubiquitin ligase LOG2 plays a significant role in the regulation of amino acid export from plant cells.

Attachment of ubiquitin to substrate proteins is catalyzed by the three enzymes E1, E2 (ubiquitin conjugating [UBC]), and E3 (ubiquitin ligase). Forty-one functional proteins with a UBC domain and active-site cysteine are predicted in the Arabidopsis (Arabidopsis thaliana) genome, which includes four that are predicted or shown to function with ubiquitin-like proteins. Only nine were previously characterized biochemically as ubiquitin E2s. We obtained soluble protein for 22 of the 28 uncharacterized UBCs after expression in Escherichia coli and demonstrated that 16 function as ubiquitin E2s. Twelve, plus three previously characterized ubiquitin E2s, were also tested for the ability to catalyze ubiquitination in vitro in the presence of one of 65 really interesting new gene (RING) E3 ligases. UBC22, UBC19-20, and UBC1-6 had variable levels of E3-independent activity. Six UBCs were inactive with all RINGs tested. Closely related UBC8, 10, 11, and 28 were active with the largest number of RING E3s and with all RING types. Expression analysis was performed to determine whether E2s or E3s were expressed in specific organs or under specific environmental conditions. Closely related E2s show unique patterns of expression and most express ubiquitously. Some RING E3s are also ubiquitously expressed; however, others show organ-specific expression. Of all the organs tested, RING mRNAs are most abundant in floral organs. This study demonstrates that E2 diversity includes examples with broad and narrow specificity toward RINGs, and that most ubiquitin E2s are broadly expressed with each having a unique spatial and developmental pattern of expression.

Approximately 5% of the Arabidopsis (Arabidopsis thaliana) proteome is predicted to be involved in the ubiquitination/26S proteasome pathway. The majority of these predicted proteins have identity to conserved domains found in E3 ligases, of which there are multiple types. The RING-type E3 is characterized by the presence of a cysteine-rich domain that coordinates two zinc atoms. Database searches followed by extensive manual curation identified 469 predicted Arabidopsis RING domain-containing proteins. In addition to the two canonical RING types (C3H2C3 or C3HC4), additional types of modified RING domains, named RING-v, RING-D, RING-S/T, RING-G, and RING-C2, were identified. The modified RINGs differ in either the spacing between metal ligands or have substitutions at one or more of the metal ligand positions. The majority of the canonical and modified RING domain-containing proteins analyzed were active in in vitro ubiquitination assays, catalyzing polyubiquitination with the E2 AtUBC8. To help identity regions of the proteins that may interact with substrates, domain analyses of the amino acids outside the RING domain classified RING proteins into 30 different groups. Several characterized protein-protein interaction domains were identified, as well as additional conserved domains not described previously. The two largest classes of RING proteins contain either no identifiable domain or a transmembrane domain. The presence of such a large and diverse number of RING domain-containing proteins that function as ubiquitin E3 ligases suggests that target-specific proteolysis by these E3 ligases is a complex and important part of cellular regulation in Arabidopsis.

Present address: Department of Trait and Technology Development, Pioneer Hi-Bred International, Inc., 7250 NW 62nd Avenue, Johnston, IA 50131, USA. Present address: Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121, USA. INNER NO OUTER (INO) expression is limited to the abaxial cell layer of the incipient and developing outer integument in Arabidopsis ovules. Using deletion analysis of the previously defined INO promoter (P-INO), at least three distinct regions that contribute to the endogenous INO expression pattern were identified. One such positive element, designated POS9, which comprises at least three distinct subelements, was found to include sufficient information to duplicate the INO expression pattern when four or more copies were used in conjunction with a heterologous minimal promoter. While known regulators of INO, including INO, SUPERMAN, BELL1, and AINTEGUMENTA, did not detectably interact with POS9 in yeast one-hybrid assays, two groups of proteins that interact specifically with POS9 were identified in one-hybrid library screens. Members of one group include C2H2 zinc finger motifs. Members of the second group contain a novel, conserved DNA-binding region and were designated the BASIC PENTACYSTEINE (BPC) proteins on the basis of conserved features of this region. The BPC proteins are nuclear localized and specifically bind in vitro to GA dinucleotide repeats located within POS9. The widespread expression patterns of the BPCs and the large number of GA repeat potential target sequences in the Arabidopsis genome indicate that BPC proteins may affect expression of genes involved in a variety of plant processes.

Appropriate methylation of genomes is essential for gene regulation. Here, we describe the six-member ORTHRUS (ORTH) gene family of Arabidopsis thaliana that plays a role in DNA methylation in vivo. ORTH1- ORTH5 are predicted to encode proteins that contain one plant homeodomain (PHD), two really interesting new gene (RING) domains, and one set ring associated (SRA) domain, whereas ORTHlike-1 encodes a protein with only one RING and SRA domain. cDNAs for ORTH1, ORTH2, ORTH5 and ORTHlike-1 were isolated, and when expressed as glutathione-S-transferase (GST) fusion proteins, were capable of promoting ubiquitylation in vitro with the E2 AtUBC11. ORTH1 promotes ubiquitylation when paired with additional AtUBC8 family members. ORTH1 proteins with substitutions in metal-ligand binding residues in each ORTH1 RING domain individually, and ORTH1 truncation derivatives lacking one or both RING domains, were tested for their ability to catalyze ubiquitylation in vitro. In these assays, either ORTH1 RING domain is capable of promoting ubiquitylation. The PHD alone is not active as an E3 ligase, nor is it required for ligase activity. GFP-ORTH1 and GFP-ORTH2 are nuclear-localized in transgenic Arabidopsis plants. Overexpression of ORTH1 or ORTH2 in Arabidopsis leads to an altered flowering time. Inspection of DNA methylation at FWA and Cen180 repeats revealed hypomethylation when ORTH proteins were overexpressed. Once initiated, a late-flowering phenotype persisted in the absence of the ORTH transgene, consistent with epigenetic effects at FWA. We conclude that ORTH proteins are E3 ligases mediating DNA methylation status in vivo.

Yuchen Lee et al., We have developed a simple method for isolating and purifying plasma membrane proteins from various cell types. This one-step affinity-chromatography method uses the property of the lectin concanavalin A (ConA) and the technique of magnetic bead separation to obtain highly purified plasma membrane proteins from crude membrane preparations or cell lines. ConA is immobilized onto magnetic beads by binding biotinylated ConA to streptavidin magnetic beads. When these ConA magnetic beads were used to enrich plasma membranes from a crude membrane preparation, this procedure resulted in 3.7-fold enrichment of plasma membrane marker 5′-nucleotidase activity with 70% recovery of the activity in the crude membrane fraction of rat liver. In agreement with the results of 5′-nucleotidase activity, immunoblotting with antibodies specific for a rat liver plasma membrane protein, CEACAM1, indicated that CEACAM1 was enriched about threefold relative to that of the original membranes. In similar experiments, this method produced 13-fold enrichment of 5′-nucleotidase activity with 45% recovery of the activity from a total cell lysate of PC-3 cells and 7.1-fold enrichment of 5′-nucleotidase activity with 33% recovery of the activity from a total cell lysate of HeLa cells. These results suggest that this one-step purification method can be used to isolate total plasma membrane proteins from tissue or cells for the identification of membrane biomarkers. © 2008 Elsevier Inc., The work was supported by National Institutes of Health Grant 2 R25 CA09481

N effort to revitalize the technical excellence of the workforce at Arnold Engineering Development Center (AEDC) to include military, civilian, and contractor personnel has been initiated. Since its inception the center has provided world-class subject matter experts on the collection, validation, and analysis of ground-test data in support of most major military weapon system development programs. Over a period of years reductions in budget, changes in funding policies, and acquisition reforms have had an unintended consequence of restricting the engineers and scientists at AEDC from developing and applying their analytical skills. In addition, the accumulation of well-meaning processes and controls has further stifled development of ground-testing technical expertise. More emphasis has been placed on having test engineers manage cost and schedule of test projects eroding the time available to evaluate the test environments and systems under test (SUT). In response to these trends, we argue the Department of Defense (DoD) has put too much emphasis on improving the efficiency of testing (faster and cheaper tests, fewer facilities, fewer personnel) and not enough emphasis on good systems engineering and enhancing the effectiveness of testing (catching system defects early). This misplaced emphasis fails to address the root causes for excessive cost and schedule delays in major acquisition programs. AEDC believes having experienced scientists and engineers with appropriate testing domain knowledge is critical to increasing the effectiveness of test and evaluation (T&E) in acquisition programs, hence, the renewed emphasis on building technical expertise. This paper describes the issues, the plan developed at AEDC to address the issues, and the broader context in which the desired changes are taking place.

Summary Epigenetic gene silencing suppresses transposon activity and is critical for normal development [1, 2]. Two common epigenetic gene-silencing marks are DNA methylation and histone H3 lysine 9 dimethylation (H3K9me2) [1]. In Arabidopsis thaliana , H3K9me2, catalyzed by the methyltransferase KRYPTONITE (KYP/SUVH4), is required for maintenance of DNA methylation outside of the standard CG sequence context [3, 4]. Additionally, loss of DNA methylation in the met1 mutant correlates with a loss of H3K9me2 [5, 6]. Here we show that KYP-dependent H3K9me2 is found at non-CG methylation sites in addition to those rich in CG methylation. Furthermore, we show that the SRA domain of KYP binds directly to methylated DNA, and SRA domains with missense mutations found in loss-of-function kyp mutants have reduced binding to methylated DNA in vitro. These data suggest that DNA methylation is required for the recruitment or activity of KYP and suggest a self-reinforcing loop between histone and DNA methylation. Lastly, we found that SRA domains from two Arabidopsis SRA-RING proteins also bind methylated DNA and that the SRA domains from KYP and SRA-RING proteins prefer methylcytosines in different sequence contexts. Hence, unlike the methyl-binding domain (MBD), which binds only methylated-CpG sequences, the SRA domain is a versatile new methyl-DNA-binding motif.

The United States Department of Defense (DoD) has designated Hypersonics a transformational technology. This study is focused on the systems development test and evaluation (T&E) of air-breathing high-speed and hypersonic (HS/H) war fighting capabilities. The study includes consideration of T&E capability requirements for modeling and simulation (M&S), ground test, and flight test and addresses potential T&E science and technologies required to support future T&E requirements. The study also focuses on defining the HS/H weapon systems development capability requirements, where airbreathing propulsion is employed, necessary over the next 15 years to successfully develop and sustain weapon system and access to space capabilities currently emerging from HS/H technologies. In 2004 the National Aerospace Initiative (NAI) refocused Service and DARPA HS/H Science and Technology (S&T) spending to mature HS/H expendable and reusable weapons and space technologies at targeted “off-ramps” in 2010, 2015, and 2020. There is enough confidence in the potential of HS/H technology that mission applications ascribed to the NAI HS/H technologies clearly indicate HS/H weapon systems are emerging as viable and attractive solutions to a number of DoD capability requirements. The U. S. Office of the Secretary of Defense, Director of Operational Test and Evaluation (OSD, DOT&E), directed that a study be performed (1) to reexamine the ability of existing DoD and NASA infrastructure to support required engineering and systems development of HS/H technologies into weapon systems and (2) to produce an HS/H T&E capability requirements roadmap to guide investments in M&S, ground-test, and flight-test capabilities and related facilities studies/research needed. Not surprisingly, this study has reaffirmed the conclusions of scientists and engineers in numerous previous studies. The current U. S. national Research Development Test and Evaluation (RDT&E) infrastructure is inadequate to effectively and efficiently transform most emerging HS/H technologies into military flight systems capabilities. The modeling and simulation, ground, and flight evaluation infrastructure must be upgraded so that the products of S&T can be applied to the development of advanced weapon systems.

The need to streamline the acquisition process of aerospace systems requires new approaches to improve the associated test and evaluation. A holistic approach to development, called Integrated Test and Evaluation (IT&E), has been under development the past few years and has shown great promise in reducing the time and cost for system development. IT&E is the synergistic combination of modeling, ground testing, and flight testing to reduce the test assets required for development of a system. Recognizing that the purpose of T&E is to create knowledge for decision making and risk reduction, an extension of the IT&E process is proposed which emphasizes modeling and simulation as a structure for a T&E knowledge base. The utility of modeling and simulation as a unifying 'backbone' that connects the T&E community into a virtual organization is outlined. The potential of a knowledge based systems approach to T&E for streamling the development process is identified. The streamlining process should result in a better operational product at less cost and time. "L/

Contractions were elicited by field stimulation and norepinephrine in canine cutaneous arteries in Krebs-bicarbonate and Krebs-Tris media and the effect of angiotensin II, 1 × 10–7 m, on these responses was determined. The absolute magnitude of the field stimulation responses was much greater in the bicarbonate buffer. Angiotensin caused potentiation in both media of the responses to field stimulation and norepinephrine. In Tris buffer with 5 mM calcium the responses to field stimulation and norepinephrine were greater than in 2.5 mM calcium, however; the degree of potentiation caused by angiotensin was similar at both calcium concentrations. The angiotensin potentiating effect in vitro appears to involve a postsynaptic action of the polypeptide which is not affected by alteration of calcium concentration or the medium.

Blood pressure and renal blood flow were monitored in conscious normotensive and two-kidney one-clip Goldblatt hypertensive dogs. Captopril administered IV in a single dose of 0.1 mg/kg to normotensives increased renal blood flow by 26.8 ± 7.6% and decreased renal vascular resistance, but did not significantly change blood pressure. Cumulative doses of 0.1 and 0.2 mg/kg increased renal blood flow by 29.9± 6.5%, and decreased renal vascular resistance and blood pressure significantly. Qualitatively similar changes in blood flow and vascular resistance of the contralateral kidney were obtained in the hypertensives. Blood pressure was reduced by a mean of 11.8 ± 4.5 mm Hg, renal blood flow increased by 36.2 ± 7.9% by the low dose, blood pressure decreased by 18.4 ± 2.7 mm Hg, and renal blood flow increased by 42.3 ± 11.4% by cumulative doses of the inhibitor. Plasma renin activity was increased by captopril in the normotensives and a greater increase in plasma renin activity was obtained in the hyper...

I F, as many scholars suggest, 1 our current rhetorical climate is characterized by increasing irrationalism, it would seem advisable for speech educators to take a closer look at the phenomenon of propaganda and the methods available for teaching students to resist its impact. Although many scholars have examined propaganda from a descriptive point-ofview, experimentalists in speech have shown comparatively little interest in the topic.