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Papers by jyoti rana

Journal of Clinical Investigation, 2021

Chandipura virus (CHPV) has recently emerged as an extremely lethal human pathogen in the family ... more Chandipura virus (CHPV) has recently emerged as an extremely lethal human pathogen in the family Rhabdoviridae and is linked to significant encephalitis outbreaks in different parts of India. The biology of CHPV remains less studied to date and the availability of reagents such as purified proteins can enhance research in this direction. In this study, we have overexpressed four of the CHPV proteins namely Nucleoprotein (N), Phosphoprotein (P), Matrix protein (M) and Glycoprotein (G) using three distinct tags in bacterial system and with changes in inducer concentration, growth and solubilisation conditions successfully purified M and G proteins for the first time along with N and P. Furthermore, the interactions of CHPV M protein with other viral proteins (G, N and P) was investigated using ELISA and GST pull down assays to show the utility of solubilised proteins. The results of both the assays demonstrated that M protein interacts with both G and N proteins, while it does not int...

Cellular Immunology, 2020

Journal of General Virology, 2019

Research in …

Abstract: Chandipura virus (CHPV) has recently emerged as an extremely lethal human pathogen in t... more Abstract: Chandipura virus (CHPV) has recently emerged as an extremely lethal human pathogen in the family Rhabdoviridae and is linked to significant encephalitis outbreaks in different parts of India. The biology of CHPV remains less studied to date and the ...

Archives of Virology, 2012

Acta Tropica, 2014

Chandipura virus (CHPV) is an arthropod borne rhabdovirus associated with acute encephalitis in c... more Chandipura virus (CHPV) is an arthropod borne rhabdovirus associated with acute encephalitis in children below the age of 15 years in the tropical states of India. Although the entry of the virus into the nervous system is among the crucial events in the pathogenesis of CHPV, the exact mechanism allowing CHPV to invade the central nervous system (CNS) is currently poorly understood. In the present review, based on the knowledge of host interactors previously predicted for CHPV, along with the support from experimental data available for other encephalitic viruses, the authors have speculated the various plausible modes by which CHPV could surpass the blood-brain barrier and invade the CNS to cause encephalitis whilst evading the host immune surveillance. Collectively, this review provides a conservative set of potential interactions that can be employed for future experimental validation with a view to better understand the neuropathogenesis of CHPV.

Molecular Therapy - Methods & Clinical Development

Proceedings

The assembly and secretion of flaviviruses are part of an elegantly regulated process. During mat... more The assembly and secretion of flaviviruses are part of an elegantly regulated process. During maturation, the viral polyprotein undergoes several co-and post-translational cleavage events mediated by both viral and host proteases. Among these, sequential cleavage at the N-and C-termini of the hydrophobic capsid anchor (Ca) at the junction of C-PrM has been considered essential for the production of flaviviruses. Here, using a refined dengue pseudovirus production system, we show that Ca plays a key role in the processing efficiency of dengue virus type 2 (DENV2) structural proteins and the assembly of viral particles. The replacement of the relatively short DENV2 Ca with the homologous regions from West Nile or Zika viruses or, alternatively, the increase in its length, improved cleavage, and hence particle assembly. Furthermore, we show that the substitution of the Ca conserved proline residue (Pro-110), as alanine abolishes pseudovirus production, regardless of the Ca sequence length. Using two experimental approaches, we investigated the need for sequential cleavage (first on the cytosolic side, then on the luminal side) and found that, while cleavage at the Ca-Pr boundary is essential for the assembly of infective particles, the same is not true for cleavage at the C-Ca boundary. We show that both the mature (C) and unprocessed capsids (C-Ca) of DENV2 were equally efficient in packaging the viral RNA and in assembling the infective particles. This was further confirmed with mutants, in which cleavage at the luminal side, by the signal peptidase, occurred independently of cleavage at the cytosolic side, by the viral NS2B/NS3 protease. We thus demonstrate that, unlike other flaviviruses, DENV2 capsid does not require a cleavable Ca sequence and that sequential cleavage is not an obligatory requirement for the morphogenesis of infective particles.

Current Bioactive Compounds

Viruses

Proteolytic processing of flavivirus polyprotein is a uniquely controlled process. To date, the s... more Proteolytic processing of flavivirus polyprotein is a uniquely controlled process. To date, the sequential cleavage of the capsid anchor sequence at the junction of C-PrM has been considered essential for the production of flaviviruses. In this study, we used two experimental approaches to show the effect of unprocessed capsid on the production and infectivity of dengue virus 2 (DENV2) pseudoviral particles. The results showed that (1) both mature and unprocessed capsids of DENV2 were equally efficient in the viral RNA packaging and also in the assembly of infective particles; (2) DENV2 variants, in which the viral and host mediated cleavage of Ca peptide were independent, produced significantly higher levels of infective particles. Overall, this study demonstrated that unlike other flaviviruses, DENV2 capsid does not require a cleavable Ca sequence, and the sequential cleavage is not an obligatory requirement for the morphogenesis of infective pseudoviral particles.

Journal of Virology

The flavivirus capsid protein (C) is separated from the downstream premembrane (PrM) protein by a... more The flavivirus capsid protein (C) is separated from the downstream premembrane (PrM) protein by a hydrophobic sequence named capsid anchor (Ca). During polyprotein processing, Ca is sequentially cleaved by the viral NS2B/NS3 protease on the cytosolic side and by signal peptidase on the luminal side of the endoplasmic reticulum (ER). To date, Ca is considered important mostly for directing translocation of PrM into the ER lumen. In this study, the role of Ca in the assembly and secretion of Zika virus was investigated using a pseudovirus-based approach. Our results show that, while Ca-mediated anchoring of C to the ER membrane is not needed for the production of infective particles, Ca expression in cis with respect to PrM is strictly required to allow proper assembly of infectious particles. Finally, we show that the presence of heterologous, but not homologous, Ca induces degradation of E through the autophagy/lysosomal pathway. IMPORTANCE The capsid anchor (Ca) is a single-pass tr...

PLOS ONE

Dengue virus (DENV), the causative agent of dengue disease, is among the most important mosquito-... more Dengue virus (DENV), the causative agent of dengue disease, is among the most important mosquito-borne pathogens worldwide. DENV is composed of four closely related serotypes and belongs to the Flaviviridae family alongside other important arthropod-borne viral pathogens such as Zika virus (ZIKV), West Nile virus (WNV) and Yellow Fever virus (YFV). After infection, the antibody response is mostly directed to the viral E glycoprotein which is composed of three structural domains named DI, DII and DIII that share variable degrees of homology among different viruses. Recent evidence supports a close serological interaction between ZIKV and DENV. The possibility of worse clinical outcomes as a consequence of antibody-dependent enhancement of infection (ADE) due to cross-reactive antibodies with poor neutralisation activity is a matter of concern. We tested polyclonal sera from groups of female Balb/C mice vaccinated with DNA constructs expressing DI/DII, DIII or the whole sE from different DENV serotypes and compared their activity in terms of cross-reactivity, neutralisation of virus infection and ADE. Our results indicate that the polyclonal antibody responses against the whole sE protein are highly cross-reactive with strong ADE and poor neutralisation activities due to DI/DII immunodominance. Conversely, anti-DIII polyclonal antibodies are type-specific, with no ADE towards ZIKV, WNV and YFV, and strong neutralisation activity restricted only to DENV.

Asian Journal of Pharmaceutical and Clinical Research, Nov 1, 2014

Objective: The severity and spread of Chikungunya fever in absence of effective antiviral therapy... more Objective: The severity and spread of Chikungunya fever in absence of effective antiviral therapy presents a serious public health threat. The present investigation aims to generate soluble and purified viral structural proteins that can be utilized to facilitate generation of reagents for development of both diagnostic and therapeutic measures. Methods: Bacterial expression system was used for optimization of expression and solubilization of structural proteins of CHIKV (Capsid, 6K and envelope proteins 1-3 [E1, E2 and E3]) as fusions with large (GST) and small (His and Strep) tags on a single platform. Affinity chromatography was used for small scale purification of viral proteins. Result: The effect of different tags, inducer concentrations, temperatures and duration of induction on solubilization of proteins has been optimized and small scale purification of all the structural proteins has been attempted. Utility of these solubilized proteins has been shown by analyzing the interaction of E2 with all the structural proteins using pull down assay. Conclusion: Small scale purification of all five structural proteins and ectodomains of envelope proteins E1 and E2 has been standardized. The data and reagents generated can be utilized for large scale purification and studying CHIKV biology.

Journal of advanced pharmaceutical technology & research

During a screening program for antimicrobial compounds from underexplored habitats, a Gram-positi... more During a screening program for antimicrobial compounds from underexplored habitats, a Gram-positive bacterium TD-032, was isolated from arid soil, Thar Desert (India), and analyzed for its morphological, physicochemical, and antimicrobial properties. The 16S ribosomal DNA (rDNA) sequence of the isolate was further studied for the novelty of γ-hyper variable region. TD-032 was grown in large-scale culture, and aqueous and organic solvent extracts analyzed for antimicrobial activity. Culture characteristics showed a lack of diffusible and melanoid pigments. The morphological features were pale yellow aerial mycelium colony color with brownish yellow substrate mycelium and leathery texture. The isolate could grow at 1% concentration of sodium chloride, temperature of 40°C, and a wide range of pH (7.0-12.0). An evaluation for extracellular enzymatic activities showed secretion of gelatinase(s), cellulase(s), and lipase(s). The γ-hyper variable region of 16S rDNA sequence of TD-032 showe...

Acta Tropica, 2015

The rhabdovirus matrix (M) protein is a multifunctional virion protein that plays major role in v... more The rhabdovirus matrix (M) protein is a multifunctional virion protein that plays major role in virus assembly and budding, virus-induced inhibition of host gene expression and cytopathic effects observed in infected cells. The myriad roles played by this protein in the virus biology make it a critical player in viral pathogenesis. Therefore, discerning the interactions of this protein with host can greatly facilitate our understanding of virus infections, ultimately leading to both improved therapeutics and insight into cellular processes. Chandipura virus (CHPV; Family Rhabdoviridae, Genus Vesiculovirus) is an emerging rhabdovirus responsible for several outbreaks of fatal encephalitis among children in India. The present study aims to screen the human fetal brain cDNA library for interactors of CHPV M protein using yeast two-hybrid system. Ten host protein interactors were identified, three of which were further validated by affinity pull down and protein interaction ELISA. The study identified novel human host interactors for CHPV which concurred with previously described associations in other human viruses.

Virus Genes, 2015

The envelope proteins of Chikungunya virus (CHIKV) are known to play crucial roles in viral infec... more The envelope proteins of Chikungunya virus (CHIKV) are known to play crucial roles in viral infection and spread. Although the role of envelope proteins in viral infection has been studied, the cellular interactors of these proteins are still elusive. In the present study, the ectodomains of CHIKV envelope proteins (E1 and E2) have been used for a high throughput yeast two-hybrid (Y2H) screening to identify the interacting host protein partners. Following a comparative analysis between the viral-host protein interaction data generated from Y2H and computational approach, five host proteins interacting with E1 and three host proteins interacting with E2 common to both datasets were identified. These associations were further verified independently by pull down and protein interaction ELISA. The identified interactions shed light on the possible cellular machinery that CHIKV might be employing during viral entry, trafficking, and evasion of immune system.