RESUMEN
OBJECTIVES: The causes for persistently high and increasing maternal mortality rates in the United States have been elusive. METHODS: We use the shift in the ideological direction of the Republican and the Democratic parties in the 1960s, to test the hypothesis that fluctuations in overall and race-specific maternal mortality rates (MMR) follow the power shifts between the parties before and after the Political Realignment (PR) of the 1960s. RESULTS: Using time-series data analysis methods, we find that, net of trend, overall and race-specific MMRs were higher under Democratic administrations than Republican ones before the PR (1915-1965)-i.e., when the Democratic Party was a protector of the Jim Crow system. This pattern, however, changed after the PR (1966-2007), with Republican administrations underperforming Democratic ones-i.e., during the period when the Republican Party shifted toward a more economically and socially conservative agenda. The pre-post PR partisan shifts in MMRs were larger for Black (9.5%, p < . 01 ) relative to White mothers (7.4%, p < . 05 ) during the study period. CONCLUSIONS FOR PRACTICE: These findings imply that parties and the ideological direction of their agendas substantively affect the social determinants of maternal health and produce politized health outcomes.
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Mortalidad Materna , Políticas , Estados Unidos/epidemiología , Humanos , PolíticaRESUMEN
Rotavirus double-layered particles (DLPs) are studied in the gas phase with a high-resolution differential mobility analyzer (DMA). DLPs were transferred to 10 mM aqueous ammonium acetate, electrosprayed into the gas phase, converted into primarily singly charged particles, and DMA-analyzed. Up to seven slightly different conformations were resolved, whose apparently random, fast (minutes), and reversible interconversions were followed in real time. They sometimes evolved into just two distinct structures, with periods of one dominating over the other and vice versa. Differences between the DLP structures in solution and in the gas phase are clearly revealed by the smaller DLP diameter found here (60 versus 70 nm). Nevertheless, we argue that the multiple gas-phase conformers observed originate in as many conformations pre-existing in solution. We further hypothesize that these conformers correspond to incomplete DLPs having lost some of the VP6 trimer quintets surrounding each of the 12 5-fold axes. Instances of this peculiar loss have been previously documented by cryoelectron microscopy for the rotavirus Wa strain, as well as via charge detection mass spectrometry for five other rotavirus strains included in the RotaTec vaccine. Evidence of this loss systematically found for all 7 rotavirus types so far studied in aqueous ammonium acetate may be a special feature of this electrolyte.
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Rotavirus , Microscopía por Crioelectrón , Rotavirus/química , Proteínas de la CápsideRESUMEN
There is growing evidence on the negative effects of perceived discrimination on health outcomes and their interactions with indicators of socioeconomic status. However, less has been studied on whether income and education lead individuals of a different race to encounter different discriminatory experiences in their lifetime. Using data from the national survey of the Midlife Development in the United States-MIDUS 1 (1995-1996) and MIDUS Refresher (2011-2014)-on eight measures of perceived lifetime discrimination, this study compares discriminatory experiences of Black and White persons in two time periods. We applied generalized structural equation models and generalized linear models to test multiplicative effects of income and education by race on lifetime discrimination. In both periods, we find substantive disparities between White and Black people in all types of lifetime discrimination, with Black people reporting much higher levels of discrimination. Such disparities exacerbated in the top cohorts of society, yet these associations have changed in time, with White individuals reporting increasing levels of discrimination. Results show that, for Black people in the mid-1990s, perceived discrimination increased as education and income increased. This finding persisted for education by the early 2010s; income effects changed as now both, low- and high-income Black people, reported the highest levels of discrimination. These findings highlight a policy conundrum, given that increasing income and education represent a desirable course of action to improve overall discrimination and health outcomes. Yet, we show that they may unintendingly exacerbate racial disparities in discrimination. We also show that the U.S. is moving toward a stagnation period in health outcomes improvement, with racial disparities in discrimination shrinking at the expense of a deterioration of whites' lifetime discriminatory experiences. Our results highlight the need for a multi-systems policy approach to prevent all forms of discrimination including those due to historical, institutional, legal, and sociopolitical structures.
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Negro o Afroamericano , Discriminación Percibida , Blanco , Humanos , Escolaridad , Renta , Estados UnidosRESUMEN
The US two-party system was transformed in the 1960s when the Democratic Party abandoned its Jim Crow protectionism to incorporate the policy agenda fostered by the civil rights movement, and the Republican Party redirected its platform toward socioeconomic and racial conservatism. The authors argue that the policy agendas promoted by the two parties through presidents and state legislatures codify a racially patterned access to resources and power detrimental to the health of all. To test the hypothesis that fluctuations in overall and race-specific infant mortality rates (IMRs) shift between the parties in power before and after the political realignment (PR), the authors apply panel data analysis methods to state-level data from the National Center for Health Statistics for the period 1915 through 2017. Net of trend, overall, and race-specific IMRs were not statistically different between presidential parties before the PR. This pattern, however, changed after the PR, with Republican administrations consistently underperforming Democratic ones. Net of trend, non-Southern state legislatures controlled by Republicans underperform Democratic ones in overall and racial IMRs in both periods.
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Salud del Lactante , Política , Agencias Gubernamentales , Humanos , Lactante , Reuniones Masivas , Políticas , Estados UnidosRESUMEN
Despite their diversity, most double-stranded-RNA (dsRNA) viruses share a specialized T=1 capsid built from dimers of a single protein that provides a platform for genome transcription and replication. This ubiquitous capsid remains structurally undisturbed throughout the viral cycle, isolating the genome to avoid triggering host defense mechanisms. Human picobirnavirus (hPBV) is a dsRNA virus frequently associated with gastroenteritis, although its pathogenicity is yet undefined. Here, we report the cryo-electron microscopy (cryo-EM) structure of hPBV at 2.6-Å resolution. The capsid protein (CP) is arranged in a single-shelled, â¼380-Å-diameter T=1 capsid with a rough outer surface similar to that of dsRNA mycoviruses. The hPBV capsid is built of 60 quasisymmetric CP dimers (A and B) stabilized by domain swapping, and only the CP-A N-terminal basic region interacts with the packaged nucleic acids. hPBV CP has an α-helical domain with a fold similar to that of fungal partitivirus CP, with many domain insertions in its C-terminal half. In contrast to dsRNA mycoviruses, hPBV has an extracellular life cycle phase like complex reoviruses, which indicates that its own CP probably participates in cell entry. Using an in vitro reversible assembly/disassembly system of hPBV, we isolated tetramers as possible assembly intermediates. We used atomic force microscopy to characterize the biophysical properties of hPBV capsids with different cargos (host nucleic acids or proteins) and found that the CP N-terminal segment not only is involved in nucleic acid interaction/packaging but also modulates the mechanical behavior of the capsid in conjunction with the cargo.IMPORTANCE Despite intensive study, human virus sampling is still sparse, especially for viruses that cause mild or asymptomatic disease. Human picobirnavirus (hPBV) is a double-stranded-RNA virus, broadly dispersed in the human population, but its pathogenicity is uncertain. Here, we report the hPBV structure derived from cryo-electron microscopy (cryo-EM) and reconstruction methods using three capsid protein variants (of different lengths and N-terminal amino acid compositions) that assemble as virus-like particles with distinct properties. The hPBV near-atomic structure reveals a quasisymmetric dimer as the structural subunit and tetramers as possible assembly intermediates that coassemble with nucleic acids. Our structural studies and atomic force microscopy analyses indicate that hPBV capsids are potentially excellent nanocages for gene therapy and targeted drug delivery in humans.
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Proteínas de la Cápside/química , Cápside/ultraestructura , Microscopía por Crioelectrón/métodos , Picobirnavirus/genética , Picobirnavirus/metabolismo , Cápside/metabolismo , Proteínas de la Cápside/genética , Genoma Viral , Humanos , Modelos Moleculares , Conformación Proteica , Conformación Proteica en Hélice alfa , Dominios Proteicos , ARN Bicatenario , Virión/ultraestructura , Ensamble de VirusRESUMEN
Unlike their counterparts in bacterial and higher eukaryotic hosts, most fungal viruses are transmitted intracellularly and lack an extracellular phase. Here we determined the cryo-EM structure at 3.7 Å resolution of Rosellinia necatrix quadrivirus 1 (RnQV1), a fungal double-stranded (ds)RNA virus. RnQV1, the type species of the family Quadriviridae, has a multipartite genome consisting of four monocistronic segments. Whereas most dsRNA virus capsids are based on dimers of a single protein, the ~450-Å-diameter, T = 1 RnQV1 capsid is built of P2 and P4 protein heterodimers, each with more than 1000 residues. Despite a lack of sequence similarity between the two proteins, they have a similar α-helical domain, the structural signature shared with the lineage of the dsRNA bluetongue virus-like viruses. Domain insertions in P2 and P4 preferential sites provide additional functions at the capsid outer surface, probably related to enzyme activity. The P2 insertion has a fold similar to that of gelsolin and profilin, two actin-binding proteins with a function in cytoskeleton metabolism, whereas the P4 insertion suggests protease activity involved in cleavage of the P2 383-residue C-terminal region, absent in the mature viral particle. Our results indicate that the intimate virus-fungus partnership has altered the capsid genome-protective and/or receptor-binding functions. Fungal virus evolution has tended to allocate enzyme activities to the virus capsid outer surface.
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Proteínas de la Cápside/metabolismo , Cápside/metabolismo , Modelos Moleculares , Virus ARN/metabolismo , Secuencia de Aminoácidos , Cápside/enzimología , Cápside/ultraestructura , Proteínas de la Cápside/química , Proteínas de la Cápside/genética , Secuencia Conservada , Microscopía por Crioelectrón , Evolución Molecular , Imagenología Tridimensional , Mutagénesis Insercional , Conformación Proteica en Hélice alfa , Conformación Proteica en Lámina beta , Dominios y Motivos de Interacción de Proteínas , Multimerización de Proteína , Estabilidad Proteica , Virus ARN/enzimología , Virus ARN/genética , Virus ARN/ultraestructura , Alineación de Secuencia , Homología Estructural de Proteína , Propiedades de Superficie , Virión/enzimología , Virión/genética , Virión/metabolismo , Virión/ultraestructura , Xylariales/virologíaRESUMEN
To initiate infection, non-enveloped viruses must recognize a target cell and penetrate the cell membrane by pore formation or membrane lysis. Rotaviruses are non-enveloped dsRNA viruses that infect the mature intestinal epithelium. They are major etiologic agents of diarrheal disease in human infants, as well as in young individuals of various avian and mammalian species. Rotavirus entry into the cell is a complex multistep process initiated by the interaction of the tip of the viral spike with glycan ligands at the cell surface, and driven by conformational changes of the proteins present in the outer protein capsid, the viral machinery for entry. This review feeds on the abundant structural information produced for rotavirus during the past 30 years and focuses on the structure and the dynamics of the rotavirus entry machinery. We survey the current models for rotavirus entry into cells.
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Infecciones por Rotavirus , Rotavirus , Internalización del Virus , Animales , Membrana Celular/virología , Humanos , Modelos Biológicos , Rotavirus/fisiología , Infecciones por Rotavirus/patología , Infecciones por Rotavirus/virologíaRESUMEN
Social stratification is an important mechanism of human organization that helps to explain health differences between demographic groups commonly associated with socioeconomic gradients. Individuals, or group of individuals, with similar health profiles may have had different stratification experiences. This is particularly true as social stratification is a significant non-measurable source of systematic unobservable differences in both SES indicators and health statuses of disadvantage. The goal of the present study was to expand the bulk of research that has traditionally treated socioeconomic and demographic characteristics as independent, additive influences on health by examining data from the United States. It is hypothesized that variation in an index of multi-system physiological dysregulation - allostatic load - is associated with social differentiation factors, sorting individuals with similar demographic and socioeconomic characteristics into mutually exclusive econo-demographic classes. The data were from the Longitudinal and Biomarker samples of the national Study of Midlife Development in the US (MIDUS) conducted in 1995 and 2004/2006. Latent class analyses and regression analyses revealed that physiological dysregulation linked to socioeconomic variation among black people, females and older adults are associated with forces of stratification that confound socioeconomic and demographic indicators. In the United States, racial stratification of health is intrinsically related to the degree to which black people in general, and black females in particular, as a group, share an isolated status in society. Findings present evidence that disparities in health emerge from group-differentiation processes to the degree that individuals are distinctly exposed to the ecological, political, social, economic and historical contexts in which social stratification is ingrained. Given that health policies and programmes emanate from said legal and political environments, interventions should target the structural conditions that expose different subgroups to different stress risks in the first place.
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Disparidades en el Estado de Salud , Clase Social , Adulto , Negro o Afroamericano , Anciano , Anciano de 80 o más Años , Alostasis/fisiología , Biomarcadores/sangre , Femenino , Estado de Salud , Encuestas Epidemiológicas , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Análisis de Regresión , Factores Socioeconómicos , Estados UnidosRESUMEN
African swine fever is a highly contagious viral disease of mandatory declaration to the World Organization for Animal Health (OIE). The lack of available vaccines makes its control difficult; thus, African swine fever virus (ASFV) represents a major threat to the swine industry. Inactivated vaccines do not confer solid protection against ASFV. Conversely, live attenuated viruses (LAV), either naturally isolated or obtained by genetic manipulation, have demonstrated reliable protection against homologous ASFV strains, although little or no protection has been demonstrated against heterologous viruses. Safety concerns are a major issue for the use of ASFV attenuated vaccine candidates and have hampered their implementation in the field so far. While trying to develop safer and efficient ASFV vaccines, we found that the deletion of the viral CD2v (EP402R) gene highly attenuated the virulent BA71 strain in vivo Inoculation of pigs with the deletion mutant virus BA71ΔCD2 conferred protection not only against lethal challenge with the parental BA71 but also against the heterologous E75 (both genotype I strains). The protection induced was dose dependent, and the cross-protection observed in vivo correlated with the ability of BA71ΔCD2 to induce specific CD8+ T cells capable of recognizing both BA71 and E75 viruses in vitro Interestingly, 100% of the pigs immunized with BA71ΔCD2 also survived lethal challenge with Georgia 2007/1, the genotype II strain of ASFV currently circulating in continental Europe. These results open new avenues to design ASFV cross-protective vaccines, essential to fight ASFV in areas where the virus is endemic and where multiple viruses are circulating.IMPORTANCE African swine fever virus (ASFV) remains enzootic in most countries of Sub-Saharan Africa, today representing a major threat for the development of their swine industry. The uncontrolled presence of ASFV has favored its periodic exportation to other countries, the last event being in Georgia in 2007. Since then, ASFV has spread toward neighboring countries, reaching the European Union's east border in 2014. The lack of available vaccines against ASFV makes its control difficult; so far, only live attenuated viruses have demonstrated solid protection against homologous experimental challenges, but they have failed at inducing solid cross-protective immunity against heterologous viruses. Here we describe a new LAV candidate with unique cross-protective abilities: BA71ΔCD2. Inoculation of BA71ΔCD2 protected pigs not only against experimental challenge with BA71, the virulent parental strain, but also against heterologous viruses, including Georgia 2007/1, the genotype II strain of ASFV currently circulating in Eastern Europe.
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Virus de la Fiebre Porcina Africana/genética , Fiebre Porcina Africana/prevención & control , Vacunas Atenuadas/administración & dosificación , Vacunas Virales/administración & dosificación , Fiebre Porcina Africana/inmunología , Fiebre Porcina Africana/virología , Virus de la Fiebre Porcina Africana/patogenicidad , Animales , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , Células Cultivadas , Inmunización , Macrófagos/efectos de los fármacos , Macrófagos/inmunología , Macrófagos/virología , Porcinos , Proteínas Virales/genéticaRESUMEN
The infectivity of rotavirus, the main causative agent of childhood diarrhea, is dependent on activation of the extracellular viral particles by trypsin-like proteases in the host intestinal lumen. This step entails proteolytic cleavage of the VP4 spike protein into its mature products, VP8* and VP5*. Previous cryo-electron microscopy (cryo-EM) analysis of trypsin-activated particles showed well-resolved spikes, although no density was identified for the spikes in uncleaved particles; these data suggested that trypsin activation triggers important conformational changes that give rise to the rigid, entry-competent spike. The nature of these structural changes is not well understood, due to lack of data relative to the uncleaved spike structure. Here we used cryo-EM and cryo-electron tomography (cryo-ET) to characterize the structure of the uncleaved virion in two model rotavirus strains. Cryo-EM three-dimensional reconstruction of uncleaved virions showed spikes with a structure compatible with the atomic model of the cleaved spike, and indistinguishable from that of digested particles. Cryo-ET and subvolume average, combined with classification methods, resolved the presence of non-icosahedral structures, providing a model for the complete structure of the uncleaved spike. Despite the similar rigid structure observed for uncleaved and cleaved particles, trypsin activation is necessary for successful infection. These observations suggest that the spike precursor protein must be proteolytically processed, not to achieve a rigid conformation, but to allow the conformational changes that drive virus entry.
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Rotavirus/metabolismo , Virión/aislamiento & purificación , Internalización del Virus , Animales , Cápside/metabolismo , Células Cultivadas , Diarrea/microbiología , Haplorrinos , Tripsina/metabolismo , Acoplamiento ViralRESUMEN
UNLABELLED: African swine fever is one of the most devastating pig diseases, against which there is no vaccine available. Recent work from our laboratory has demonstrated the protective potential of DNA vaccines encoding three African swine fever viral antigens (p54, p30, and the hemagglutinin extracellular domain) fused to ubiquitin. Partial protection was afforded in the absence of detectable antibodies prior to virus challenge, and survival correlated with the presence of a large number of hemagglutinin-specific CD8(+) T cells in blood. Aiming to demonstrate the presence of additional CD8(+) T-cell determinants with protective potential, an expression library containing more than 4,000 individual plasmid clones was constructed, each one randomly containing a Sau3AI restriction fragment of the viral genome (p54, p30, and hemagglutinin open reading frames [ORFs] excluded) fused to ubiquitin. Immunization of farm pigs with the expression library yielded 60% protection against lethal challenge with the virulent E75 strain. These results were further confirmed by using specific-pathogen-free pigs after challenging them with 10(4) hemadsorbing units (HAU) of the cell culture-adapted strain E75CV1. On this occasion, 50% of the vaccinated pigs survived the lethal challenge, and 2 out of the 8 immunized pigs showed no viremia or viral excretion at any time postinfection. In all cases, protection was afforded in the absence of detectable specific antibodies prior to challenge and correlated with the detection of specific T-cell responses at the time of sacrifice. In summary, our results clearly demonstrate the presence of additional protective determinants within the African swine fever virus (ASFV) genome and open up the possibility for their future identification. IMPORTANCE: African swine fever is a highly contagious disease of domestic and wild pigs that is endemic in many sub-Saharan countries, where it causes important economic losses and is currently in continuous expansion across Europe. Unfortunately, there is no treatment nor an available vaccine. Early attempts using attenuated vaccines demonstrated their potential to protect pigs against experimental infection. However, their use in the field remains controversial due to safety issues. Although inactive and subunit vaccines did not confer solid protection against experimental ASFV infection, our DNA vaccination results have generated new expectations, confirming the key role of T-cell responses in protection and the existence of multiple ASFV antigens with protective potential, more of which are currently being identified. Thus, the future might bring complex and safe formulations containing more than a single viral determinant to obtain broadly protective vaccines. We believe that obtaining the optimal vaccine formulation it is just a matter of time, investment, and willingness.
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Virus de la Fiebre Porcina Africana/inmunología , Fiebre Porcina Africana/prevención & control , Inmunización/métodos , Vacunas de ADN/inmunología , Vacunas Virales/inmunología , Virus de la Fiebre Porcina Africana/genética , Animales , Expresión Génica , Biblioteca de Genes , Masculino , Plásmidos/administración & dosificación , Análisis de Supervivencia , Porcinos , Vacunas de ADN/administración & dosificación , Vacunas de ADN/genética , Vacunas Virales/administración & dosificación , Vacunas Virales/genéticaRESUMEN
Infection of cells with African swine fever virus (ASFV) can lead to the formation of zipper-like stacks of structural proteins attached to collapsed endoplasmic reticulum (ER) cisternae. We show that the collapse of ER cisternae observed during ASFV infection is dependent on the viral envelope protein, J13Lp. Expression of J13Lp alone in cells is sufficient to induce collapsed ER cisternae. Collapse was dependent on a cysteine residue in the N-terminal domain of J13Lp exposed to the ER lumen. Luminal collapse was also dependent on the expression of J13Lp within stacks of ER where antiparallel interactions between the cytoplasmic domains of J13Lp orientated N-terminal domains across ER cisternae. Cisternal collapse was then driven by disulphide bonds between N-terminal domains arranged in antiparallel arrays across the ER lumen. This provides a novel mechanism for biogenesis of modified stacks of ER present in cells infected with ASFV, and may also be relevant to cellular processes.
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Virus de la Fiebre Porcina Africana/fisiología , Retículo Endoplásmico/ultraestructura , Proteínas Virales/biosíntesis , Virus de la Fiebre Porcina Africana/ultraestructura , Animales , Técnicas de Cultivo de Célula , Chlorocebus aethiops , Técnica del Anticuerpo Fluorescente , Membranas Intracelulares/ultraestructura , Microscopía Electrónica de Transmisión , Plásmidos , Estructura Terciaria de Proteína , Transfección , Células Vero , Proteínas del Envoltorio Viral/biosíntesis , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/ultraestructura , Proteínas Virales/química , Proteínas Virales/ultraestructura , Ensamble de VirusRESUMEN
The function of the African swine fever virus (ASFV) reparative DNA polymerase, Pol X, was investigated in the context of virus infection. Pol X is a late structural protein that localizes at cytoplasmic viral factories during DNA replication. Using an ASFV deletion mutant lacking the Pol X gene, we have shown that Pol X is not required for virus growth in Vero cells or swine macrophages under one-step growth conditions. However, at a low multiplicity of infection, when multiple rounds of replication occur, the growth of the mutant virus is impaired in swine macrophages but not in Vero cells, suggesting that Pol X is needed to repair the accumulated DNA damage. The replication of the mutant virus in Vero cells presents sensitivity to oxidative damage, and mutational analysis of viral DNA shows that deletion of Pol X results in an increase in the mutation frequency in macrophages. Therefore, our data reveal a biological role for ASFV Pol X in the context of the infected cell in the preservation of viral genetic information.
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Virus de la Fiebre Porcina Africana/enzimología , Virus de la Fiebre Porcina Africana/genética , ADN Polimerasa Dirigida por ADN/metabolismo , Genoma Viral , Virus de la Fiebre Porcina Africana/fisiología , Animales , Chlorocebus aethiops , Reparación del ADN , ADN Polimerasa Dirigida por ADN/genética , Eliminación de Gen , Inestabilidad Genómica , Macrófagos/virología , Mutación , Porcinos , Células Vero , Replicación ViralRESUMEN
Rotavirus (RV) replication takes place in the viroplasms, cytosolic inclusions that allow the synthesis of virus genome segments and their encapsidation in the core shell, followed by the addition of the second layer of the virion. The viroplasms are composed of several viral proteins, including NSP5, which serves as the main building block. Microtubules, lipid droplets, and miRNA-7 are among the host components recruited in viroplasms. We investigated the interaction between RV proteins and host components of the viroplasms by performing a pull-down assay of lysates from RV-infected cells expressing NSP5-BiolD2. Subsequent tandem mass spectrometry identified all eight subunits of the tailless complex polypeptide I ring complex (TRiC), a cellular chaperonin responsible for folding at least 10% of the cytosolic proteins. Our confirmed findings reveal that TRiC is brought into viroplasms and wraps around newly formed double-layered particles. Chemical inhibition of TRiC and silencing of its subunits drastically reduced virus progeny production. Through direct RNA sequencing, we show that TRiC is critical for RV replication by controlling dsRNA genome segment synthesis, particularly negative-sense single-stranded RNA. Importantly, cryo-electron microscopy analysis shows that TRiC inhibition results in defective virus particles lacking genome segments and polymerase complex (VP1/VP3). Moreover, TRiC associates with VP2 and NSP5 but not with VP1. Also, VP2 is shown to be essential for recruiting TRiC in viroplasms and preserving their globular morphology. This study highlights the essential role of TRiC in viroplasm formation and in facilitating virion assembly during the RV life cycle. IMPORTANCE: The replication of rotavirus takes place in cytosolic inclusions termed viroplasms. In these inclusions, the distinct 11 double-stranded RNA genome segments are co-packaged to complete a genome in newly generated virus particles. In this study, we show for the first time that the tailless complex polypeptide I ring complex (TRiC), a cellular chaperonin responsible for the folding of at least 10% of the cytosolic proteins, is a component of viroplasms and is required for the synthesis of the viral negative-sense single-stranded RNA. Specifically, TRiC associates with NSP5 and VP2, the cofactor involved in RNA replication. Our study adds a new component to the current model of rotavirus replication, where TRiC is recruited to viroplasms to assist replication.
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Rotavirus , Rotavirus/genética , Compartimentos de Replicación Viral/metabolismo , Proteínas no Estructurales Virales/metabolismo , Microscopía por Crioelectrón , Replicación Viral/fisiología , ARN , PéptidosRESUMEN
Rotaviruses (RVs) are non-enveloped multilayered dsRNA viruses that are major etiologic agents of diarrheal disease in humans and in the young in a large number of animal species. The viral particle is composed of three different protein layers that enclose the segmented dsRNA genome and the transcriptional complexes. Each layer defines a unique subparticle that is associated with a different phase of the replication cycle. Thus, while single- and double-layered particles are associated with the intracellular processes of selective packaging, genome replication, and transcription, the viral machinery necessary for entry is located in the third layer. This modular nature of its particle allows rotaviruses to control its replication cycle by the disassembly and assembly of its structural proteins. In this review, we examine the significant advances in structural, molecular, and cellular RV biology that have contributed during the last few years to illuminating the intricate details of the RV particle disassembly and assembly processes.
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Rotavirus , Animales , Humanos , Rotavirus/genética , ARN Bicatenario , Virión/genéticaRESUMEN
Here we investigate the cargo retention of individual human picobirnavirus (hPBV) virus-like particles (VLPs) which differ in the N-terminal of their capsid protein (CP): (i) hPBV CP contains the full-length CP sequence; (ii) hPBV Δ45-CP lacks the first 45 N-terminal residues; and (iii) hPBV Ht-CP is the full-length CP with a N-terminal 36-residue tag that includes a 6-His segment. Consequently, each VLP variant holds a different interaction with the ssRNA cargo. We used atomic force microscopy (AFM) to induce and monitor the mechanical disassembly of individual hPBV particles. First, while Δ45-CP particles that lack ssRNA allowed a fast tip indentation after breakage, CP and Ht-CP particles that pack heterologous ssRNA showed a slower tip penetration after being fractured. Second, mechanical fatigue experiments revealed that the increased length in 8% of the N-terminal (Ht-CP) makes the virus particles to crumble â¼10 times slower than the wild type N-terminal CP, indicating enhanced RNA cargo retention. Our results show that the three differentiated N-terminal topologies of the capsid result in distinct cargo release dynamics during mechanical disassembly experiments because of the different interaction with RNA.
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Picobirnavirus , Humanos , Proteínas de la Cápside , Cápside , Secuencia de Aminoácidos , ARNRESUMEN
African swine fever virus (ASFV), the causative agent of one of the most devastating swine diseases, has been considered exclusively cytoplasmic, even though some authors have shown evidence of an early stage of nuclear replication. In the present study, an increment of lamin A/C phosphorylation was observed in ASFV-infected cells as early as 4 h postinfection, followed by the disassembling of the lamina network close to the sites where the viral genome starts its replication. At later time points, this and other nuclear envelope markers were found in the cytoplasm of the infected cells. The effect of the infection on the cell nucleus was much more severe than previously expected, since a redistribution of other nuclear proteins, such as RNA polymerase II, the splicing speckle SC-35 marker, and the B-23 nucleolar marker, was observed from 4 h postinfection. All this evidence, together with the redistribution, dephosphorylation, and subsequent degradation of RNA polymerase II after ASFV infection, suggests the existence of sophisticated mechanisms to regulate the nuclear machinery during viral infection.
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Virus de la Fiebre Porcina Africana/fisiología , Núcleo Celular/metabolismo , Lamina Tipo A/metabolismo , Virus de la Fiebre Porcina Africana/genética , Virus de la Fiebre Porcina Africana/metabolismo , Animales , Núcleo Celular/ultraestructura , Núcleo Celular/virología , Chlorocebus aethiops , Citoplasma/virología , Técnica del Anticuerpo Fluorescente , Hibridación in Situ , Microscopía Confocal , Membrana Nuclear/metabolismo , Membrana Nuclear/ultraestructura , Membrana Nuclear/virología , Lámina Nuclear/metabolismo , Lámina Nuclear/ultraestructura , Lámina Nuclear/virología , Proteínas Nucleares/metabolismo , Fosforilación , ARN Polimerasa II/metabolismo , Células Vero , Replicación ViralRESUMEN
INTRODUCTION: State policies and programs affect population health; yet, little is known about the connections between health and the political institutions and actors that prescribe and execute those policies and programs. METHODS: The 2-way fixed-effects regression models were fitted to data from the National Center for Health Statistics, 1969-2014, to estimate logged infant mortality rate differentials between Republican- and non-Republicanâcontrolled state legislatures. These data were used in 2020 to hypothesize that net of trend, fluctuations in infant mortality rates-overall and by race-correlate with the party that controls state legislatures (the Lower House, the Upper House, and Congress). RESULTS: Findings show that state infant and postneonatal mortality rates are substantively higher under Republican-controlled state legislatures than under non-Republicanâcontrolled ones. The effect size is larger for postneonatal than for neonatal mortality. Findings suggest that effects may be greater for Black than for White infants, although the race-specific results are estimated imprecisely. The governor's party shows no substantive impacts on infant mortality rates net of party control of the Lower House. CONCLUSIONS: Findings support the proposition that the social determinants of health are constructed, at least in part, by the power vested in governments.
Asunto(s)
Salud del Lactante , Determinantes Sociales de la Salud , Humanos , Lactante , Mortalidad Infantil , Recién Nacido , Política , Gobierno Estatal , Estados UnidosRESUMEN
One of the most characteristic features of African swine fever virus gene expression is its use of two polyproteins, pp220 and pp62, to produce several structural proteins that account for approximately 32% of the total protein virion mass. Equimolecular amounts of these proteins are the major components of the core shell, a thick protein layer that lies beneath the inner envelope, surrounding the viral nucleoid. Polyprotein pp220, which is located immediately underneath the internal envelope, is essential for the encapsidation of the core of the viral particle. In its absence, the infection produces essentially coreless particles. In this study we analyzed, by means of an IPTG (isopropyl-beta-d-thiogalactopyranoside)-inducible virus, the role of polyprotein pp62 in virus assembly. Polyprotein pp62 is indispensable for viral replication. The repression of polyprotein pp62 expression does not alter late gene expression or the proteolytic processing of the polyprotein pp220. However, it has a profound impact on the subcellular localization of polyprotein pp220. Electron microscopy studies revealed that polyprotein pp62 is necessary for the correct assembly and maturation of the core of the viral particle. Its repression leads to the appearance of a significant fraction of empty particles, to an increase in the number of immature-like particles, and to the accumulation of defective particles. Immunoelectron microscopy analysis showed a clear correlation between the amount of polyprotein pp62, the quantity of polyprotein pp220, and the state of development of the core, suggesting that the complete absence of polyprotein pp62 during morphogenesis would produce a homogenous population of empty particles.
Asunto(s)
Virus de la Fiebre Porcina Africana/fisiología , Poliproteínas/fisiología , Proteínas Virales/fisiología , Ensamble de Virus , Virus de la Fiebre Porcina Africana/química , Regulación Viral de la Expresión Génica , Proteínas Estructurales Virales , Virión , Replicación ViralRESUMEN
The first morphological evidence of African swine fever virus (ASFV) assembly is the appearance of precursor viral membranes, thought to derive from the endoplasmic reticulum, within the assembly sites. We have shown previously that protein p54, a viral structural integral membrane protein, is essential for the generation of the viral precursor membranes. In this report, we study the role of protein p17, an abundant transmembrane protein localized at the viral internal envelope, in these processes. Using an inducible virus for this protein, we show that p17 is essential for virus viability and that its repression blocks the proteolytic processing of polyproteins pp220 and pp62. Electron microscopy analyses demonstrate that when the infection occurs under restrictive conditions, viral morphogenesis is blocked at an early stage, immediately posterior to the formation of the viral precursor membranes, indicating that protein p17 is required to allow their progression toward icosahedral particles. Thus, the absence of this protein leads to an accumulation of these precursors and to the delocalization of the major components of the capsid and core shell domains. The study of ultrathin serial sections from cells infected with BA71V or the inducible virus under permissive conditions revealed the presence of large helicoidal structures from which immature particles are produced, suggesting that these helicoidal structures represent a previously undetected viral intermediate.