Biology subjects

Das, R.

Publications and source records attributed to Das, R..

At least 109 records · Page 6Linked to original sources

bioRxiv2021

Functional characterization of a DNA-dependent AAA ATPase in SimranZ1, a F cluster mycobacteriophage

Mycobacteriophages are viruses of Mycobacterium spp. with promising diagnostic and therapeutic potential. Phage genome exploration and characterization of their proteomes are essential to gain a better understanding of their role in phage biology. So far, about 2014 mycobacteriophages have been genomically defined and 1563 phage protein families (phamilies) are identified. However, the function of only a fraction (about 15%) is known and a majority of ORFs in phage genomes are hypothetical proteins. In this study, from the annotated genome of a F1 cluster mycobacteriophage SimranZ1, a putative AAA ATPase (Gp65, Pham 9410) is characterized as a DNA-dependent ATPase. Sequence-based functional annotation predicted Gp65 to belong to the P-loop NTPase superfamily, having AAA_24 and RecA/RadA domains which are known to be involved in ATP-dependent DNA repair/maintenance mechanism. On molecular docking, Gly21 and Ser23 of Gp65 showed specific binding with ATP. Using a microtiter plate assay, ATPase activity of Gp65 was experimentally verified which was found to increase in the presence of dsDNA. Gel electrophoresis under non-denaturing condition showed the oligomeric states of Gp65 and Transmission Electron Microscopy revealed it to exist as a hexamer having a prominent central pore with a diameter of 1.9 nm. In summary, functional characterization of Gp65 as a DNA dependent AAA ATPase indicates its role in DNA repair/maintenance mechanism in mycobacteriophages.

biochemistry↗

bioRxiv2021

Effect of Leaf Aqueous Extract of Manilkara hexandra on Digestive and Glucose Metabolic Enzymes, and Serum Glucose Level in Labeo rohita Fingerlings

Manilkara hexandra (Roxb.) Dubard (common name Khirni, family: Sapotaceae) is an evergreen traditionally used medicinal plant. The present study aimed to see the effects of leaf aqueous extract of M. hexandra (LAEMH) on digestive and glucose metabolic enzyme action and serum glucose level in rohu, Labeo rohita, fingerlings. Experimental fish were fed a basal diet (Group I), and diets supplemented with LAEMH at 300 mg (Group II) and 600 mg (Group III) kg-1body weight. A significant reduction in serum glucose was noticed in the treated groups when compared with the control group. The reduced amylase activity was noticed in the treated fingerlings in a dose-dependent manner. However, lipase and protease activities didnt differ significantly among the experimental groups. Reduced serum glucose level might be correlated with the decline in the activity of digestive amylase in fish. Group II (3.35{+/-}0.19 U) and Group III (3.49{+/-}0.13 U) were recorded with reduced glucose-6-phosphatase activities than the control group (4.4{+/-}0.39 U). Moreover, the study revealed a decline in fructose-1,6-phosphatase activities in the treated groups in comparison to the control group. The decline in the activities of the metabolic enzymes might be associated with the non-availability of glucose owing to reduced activity of the digestive amylase in the treated groups. In conclusion, the present study established the hypoglycaemic effect of the leaf aqueous extract of M. hexandra in a fish model.

pharmacology and toxicology↗

bioRxiv2021

Computational identification and characterization of antigenic properties of Rv3899c of Mycobacterium tuberculosis and its interaction with Human leukocyte antigen (HLA)

Tuberculosis (TB) is the second largest infectious disease that kills 1.2 million people annually worldwide. A rise in drug-resistant TB cases demands continued efforts towards the discovery & development of drugs and vaccines. In the recent past, though novel drugs have been added to the current TB regimen [1], research on new vaccine candidates needs a greater thrust. Secretory proteins of H37Rv are frequently studied for their antigenicity and their scope as protein subunit vaccines decrees further analysis. In this study, Rv3899c of H37Rv emerges as a potential vaccine candidate on its evaluation by several bioinformatics tools. It is a non-toxin, secretory protein with an immunoglobulin-like fold which does not show similarity with a human protein. We found Rv3899c homologs in several mycobacterial species and its antigenic score (0.54) to compare well with the known immunogens such as ESAT-6 (0.56) and Rv1860 (0.52). Structural examination of Rv3899c predicted ten antigenic peptides, an accessibility profile of the antigenic determinants constituting B-cell epitope rich regions and a low Abundance of Antigenic Regions (AAR) value. Significantly, our study shows ESX-2 secretion system proteins and antigenic PE/PPE proteins of H37Rv as the interacting partners of Rv3899c. Further, molecular docking predicted Rv3899c to interact with human leukocyte antigen HLA-DRB1*04:01 through its antigenically conserved motif (RAAEQQRLQRIVDAVARQEPRISWAAGLRDDGTT). Interestingly, the binding affinity was observed to increase on citrullation of its Arg1 residue. Taken together, the computational characterization and predictive information suggest Rv3899c to be a promising TB vaccine candidate, which should be examined and validated experimentally.

immunology↗

bioRxiv2021

Molecular analysis of prostate cancer: prostate tissue and urine proteomics based approach

Benign prostatic hyperplasia (BPH) and prostate cancer are the most frequently diagnosed conditions in men above 60 years. BPH manifests as benign enlargement of the prostate gland causing pain and difficulty in micturition, often associated with other lower urinary tract symptoms. On the other hand, prostate cancer might initially set in as a tumor of no clinical significance, but can ultimately develop into an aggressively metastatic cancer at later stages. Due to overlapping symptomatic manifestations with BPH, it might be difficult to diagnose prostate cancer and differentiate it from BPH. Screening for prostate cancer is based on examining the levels of prostate specific antigen (PSA), a clinical biomarker for prostate cancer in blood. However, several reported cases indicate that PSA might lack the sensitivity and specificity required to differentiate between the cancerous and benign conditions of prostate. Therefore, in the absence of non-invasive biomarkers in a diagnostic setup, an intensely invasive surgical removal of a part of the tissue and subsequent histopathologial examination is the only available procedure to confirm the cancer. In this study, we used tissue and urine proteomics platforms to profile respective proteomes in both clinical conditions. We observed that latent transforming growth factor binding protein was significantly under-expressed in the both tissue and urine proteome of prostate cancer. We propose that the down-regulation of the latent transforming growth factor binding protein 4 might be explored in a large set of patients with prostate cancer to develop a non-invasive urine based biomarker for the diagnosis of prostate cancer.

cancer biology↗

bioRxiv2021

Mechanical Stretch Inhibition SensitizesProprioceptors to Compressive Stresses

A repetitive gait cycle is an archetypical component within the behavioural repertoire of many if not all animals including humans. It originates from mechanical feedback within proprioceptors to adjust the motorprogram during locomotion and thus leads to a periodic orbit in a low dimensional space. Here, we investigate the mechanics, molecules and neurons responsible for proprioception in Caenorhabditis (C.) elegans to gain insight into how mechanosensation shapes the orbital trajectory to a well-defined limit cycle. We used genome editing, force spectroscopy and multiscale modeling and found that alternating tension and compression with the spectrin network of a single proprioceptor encodes body posture and informs TRP-4/NOMPC and TWK-16/TREK2 homologs of mechanosensitive ion channels during locomotion. In contrast to a widely accepted model of proprioceptive stretch reception, we found that proprioceptors activated under compressive stresses in vivo and in vitro, and speculate that this property is conserved across function and species.

neuroscience↗

bioRxiv2020

Deciphering colchicine like actions of clerodin in terms of microtubule destabilization based mitotic abnormalities, G2/M-phase arrest, and plant polyploidy

Clerodin (C24H34O7), a clerodane diterpenoid, is a bitter principle of Clerodendrum viscosum. The present study aimed to decipher colchicine-like actions of clerodin in terms of microtubule destabilization based mitotic abnormalities, G2-M arrest, and plant polyploidy. Purified clerodin showed increased metaphase frequency in Human Peripheral Blood Lymphocytes (HPBLs), Human Embryonic Kidney cells (HEK-293), and Allium cepa root apical meristem cells. Both squashed slide of the onion root tip and flow cytometric analysis of radish protoplast revealed a significantly increased frequency of polyploid cells. Flow cytometric analysis showed an increase in frequencies of G2-M in MCF-7 cells from 6.10 to 16.25% after clerodin (200g/mL) treatment for 24 h. Confocal microscopy imaging of tubulin in clerodin-treated MCF-7 cells revealed microtubule destabilization. Molecular docking and LIGPLOT analysis indicate that clerodin interact in the colchicine binding site, including, single hydrogen bond with Asn 101 of -tubulin. In summary, our experimental data revealed that clerodin has metaphase arresting, microtubule destabilization, and polyploidy inducing ability similar to colchicine. Molecular docking analysis revealed for the first time that clerodin and colchicine interact at the common site of tubulin residue indicating a common mechanism of action. The results also indicate similar cytotoxic potentialities of both clerodin and colchicine even though they belong to different chemical groups. Thus, clerodin may be used in place of colchicine as a plant polyploidy inducing agent in plant breeding programs in Agriculture.

cell biology↗

bioRxiv2020

Stem cell basis of a host driven transmission of antigen packed aerosols: a novel mechanism of natural vaccination for tuberculosis

Natural vaccination against pathogens are known to be achieved by herd-immunity i.e. infected human host provide immunity to the community by spreading the pathogen. Whether, infected human hosts transmit vesicle packed aerosols of pathogens antigen for natural vaccination of the community has not yet been considered. We have explored a traditional healing method of aerosol-inoculation against small pox and tuberculosis in the Sualkuchi-Hajo cultural complex of Kamarupa, an ancient Indian region known for tantra-based healing and spirituality. In the aerosol-inoculation method against TB, selected persons with TB (later identified as smear negative TB subject) are encouraged to spread good nigudah in the community by Kirtan chanting; the good Nigudah are thought to be present within bad-nigudah or invisible krimis (tiny flesh eating living being mentioned in ancient Indias medicinal text Caraka Samhita and Atharva Veda). A 15-years of contact TB investigation study, as well as laboratory study of aerosol obtained from smear negative PTB (SN-PTB) subjects led to the identification of good Nigudah as extracellular vesicles (EVs) filled with Mtb-antigen ESAT-6. We then developed a mouse model of aerosol-inoculation using SN-PTB subject derived aerosol EVs, and identified Mtb infected mesenchymal stem cells (MSCs) of the lung as the putative source of the ESAT-6+ EVs. These Mtb infected MSCs reprogram to altruistic stem cell (ASC) phenotype, which then secrete ESAT-6+ EVs to the aerosols; healthy mice receiving the aerosol develop Mtb specific herd immunity. These results expedite our ongoing work on the innate defense mechanism of ASCs against pathogen, and provide a novel mechanism of natural vaccination, where the host extracts appropriate antigens from a pathogen, and then spread it in the community via aerosols.

immunology↗

bioRxiv2020

Lipidomic profiling of clinical prostate cancer reveals targetable alterations in lipid composition

Dysregulated lipid metabolism is a prominent feature of prostate cancer that is driven by androgen receptor (AR) signaling. Herein, we used quantitative mass spectrometry to define the "lipidome" in prostate tumors with matched benign tissues (n=21), independent tissues (n=47), and primary prostate explants cultured with a clinical AR antagonist, enzalutamide (n=43). Significant differences in lipid composition were detected and spatially visualized in tumors compared to matched benign samples. Notably, tumors featured higher proportions of monounsaturated lipids overall and elongated fatty acid chains in phosphatidylinositol and phosphatidylserine lipids. Significant associations between lipid profile and malignancy were validated in unmatched samples, and PL composition was characteristically altered in patient tissues that responded to AR inhibition. Importantly, targeting of altered tumor-related lipid features, via inhibition of acetyl CoA carboxylase 1, significantly reduced cellular proliferation in tissue explants (n=13). This first characterization of the prostate cancer lipidome in clinical tissues revealed enhanced fatty acid synthesis, elongation and desaturation as tumor-defining features, with potential for therapeutic targeting.

cancer biology↗

bioRxiv2020

Impact of clade specific mutations on structural fidelity of SARS-CoV-2 proteins

The SARS-CoV-2 is a positive stranded RNA virus with a genome size of ~29.9 kilobase pairs which spans 29 open reading frames. Studies have revealed that the genome encodes about 16 non-structural proteins (nsp), four structural proteins, and six or seven accessory proteins. Based on prevalent knowledge on SARS-CoV and other coronaviruses, functions have been assigned for majority of the proteins. While, researchers across the globe are engrossed in identifying a potential pharmacological intervention to control the viral outbreak, none of the work has come up with new antiviral drugs or vaccines yet. One possible approach that has shown some positive results is by treating infected patients with the plasma collected from convalescent COVID-19 patients. Several vaccines around the world have entered their final trial phase in humans and we expect that these will in time be available for application to worldwide population to combat the disease. In this work we analyse the effect of prevalent mutations in the major pathogenesis related proteins of SARS-COV2 and attempt to pinpoint the effects of those mutations on the structural stability of the proteins. Our observations and analysis direct us to identify that all the major mutations have a negative impact in context of stability of the viral proteins under study and the mutant proteins suffer both structural and functional alterations as a result of the mutations. Our binary scoring scheme identifies L84S mutation in ORF8 as the most disruptive of the mutations under study. We believe that, the virus is under the influence of an evolutionary phenomenon similar to Mullers ratchet where the continuous accumulation of these mutations is making the virus less virulent which may also explain the reduction in fatality rates worldwide.

bioinformatics↗

bioRxiv2020

Differential expression of proteins in human prostate cancer tissues probed by MALDI imaging mass spectrometry

Histopathology, the gold-standard method for diagnosis of human prostate cancer, is based on the analysis of changes in cellular morphology and tissue architecture in chemically stained tissue sections. Even at the very early stages of cancer with minimal phenotypic changes in cellular morphologies, there might be detectable changes in the expression profiles of proteins. Over the last decade, imaging mass spectrometry has been used to explore the spatial distribution and expression profiles of several molecules with their twodimensional heterogeneity retained across the tissue section. In the present study, using MALDI mass spectrometry based tissue imaging, we report the differential expression of three proteins, vinculin, ribonuclease T2 and 60 kDa heat shock protein across human prostate tissue sections in regions pathologically demarcated as frankly malignant. In an independent analysis, quantitative proteomics revealed that in cancerous prostate tissues, ribonuclease T2 and 60 kDa heat shock protein were significantly overexpressed by 22.26- and 6 folds respectively compared to benign condition. Our results show the utility of this approach to probe differential protein expression in architecturally intact cancer tissues. In addition, we propose that ribonuclease T2 and 60 kDa heat shock protein might be developed as diagnostic biomarkers for prostate cancer in future.

biophysics↗

bioRxiv2020

Ratio of hydrophobic-hydrophilic and positive-negative residues at lipid-water-interface influences surface expression and channel-gating of TRPV1

During evolution, TRPV1 has lost, retained or selected certain residues at Lipid-Water-Interface (LWI) and formed specific patterns there. The ratio of "hydrophobic-hydrophilic" and "positive-negative charged" residues at the inner LWI remains conserved throughout vertebrate evolution and play important role in regulating TRPV1 trafficking, localization and functions. Arg575 is an important residue as Arg575Asp mutant has reduced Capsaicin-sensitivity, surface expression, colocalization with lipid-raft markers, cell area, and increased cell lethality. This lethality is due to the disruption of the ratio between positive-negative charges there. Such lethality can be rescued by either using TRPV1-specfic inhibitor 5-IRTX or by restoring the positive-negative charge ratio at that position, i.e. by introducing Asp576Arg mutation in Arg575Asp backbone. We propose that Arg575Asp mutant confers TRPV1 in a "constitutive-open-like" condition. These findings have broader implication in understanding the molecular basis of thermo-gating and channel-gating and the microenvironments involved in such process that goes erratic in different diseases.

cell biology↗

bioRxiv2020

Global and Local Mutations in Bangladeshi SARS-CoV-2 Genomes

Corona Virus Disease-2019 (COVID-19) warrants comprehensive investigations of publicly available Severe Acute Respiratory Syndrome-CoronaVirus-2 (SARS-CoV-2) genomes to gain new insight about their epidemiology, mutations and pathogenesis. Nearly 0.4 million mutations were identified so far in [~]60,000 SARS-CoV-2 genomic sequences. In this study, we compared 207 of SARS-CoV-2 genomes reported from different parts of Bangladesh and their comparison with 467 globally reported sequences to understand the origin of viruses, possible patterns of mutations, availability of unique mutations, and their apparent impact on pathogenicity of the virus in victims of Bangladeshi population. Phylogenetic analyses indicates that in Bangladesh, SARS-CoV-2 viruses might arrived through infected travelers from European countries, and the GR clade was found as predominant in this region. We found 2602 mutations including 1602 missense mutations, 612 synonymous mutations, 36 insertions and deletions with 352 other mutations types. In line with the global trend, D614G mutation in spike glycoprotein was predominantly high (95.6%) in Bangladeshi isolates. Interestingly, we found the average number of mutations in ORF1ab, S, ORF3a, M and N of genomes, having nucleotide shift at G614 (n=459), were significantly higher (p[≤]0.001) than those having mutation at D614 (n=215). Previously reported frequent mutations such as P4715L, D614G, R203K, G204R and I300F were also prevalent in Bangladeshi isolates. Additionally, 87 unique amino acid changes were revealed and were categorized as originating from different cities of Bangladesh. The analyses would increase our understanding of variations in virus genomes circulating in Bangladesh and elsewhere and help develop novel therapeutic targets against SARS-CoV-2.

genomics↗

bioRxiv2020

Theoretical basis for stabilizing messenger RNA through secondary structure design

RNA hydrolysis presents problems in manufacturing, long-term storage, world-wide delivery, and in vivo stability of messenger RNA (mRNA)-based vaccines and therapeutics. A largely unexplored strategy to reduce mRNA hydrolysis is to redesign RNAs to form double-stranded regions, which are protected from in-line cleavage and enzymatic degradation, while coding for the same proteins. The amount of stabilization that this strategy can deliver and the most effective algorithmic approach to achieve stabilization remain poorly understood. Here, we present simple calculations for estimating RNA stability against hydrolysis, and a model that links the average unpaired probability of an mRNA, or AUP, to its overall hydrolysis rate. To characterize the stabilization achievable through structure design, we compare AUP optimization by conventional mRNA design methods to results from more computationally sophisticated algorithms and crowdsourcing through the OpenVaccine challenge on the Eterna platform. These computational tests were carried out on both model mRNAs and COVID-19 mRNA vaccine candidates. We find that rational design on Eterna and the more sophisticated algorithms lead to constructs with low AUP, which we term superfolder mRNAs. These designs exhibit wide diversity of sequence and structure features that may be desirable for translation, biophysical size, and immunogenicity, and their folding is robust to temperature, choice of flanking untranslated regions, and changes in target protein sequence, as illustrated by rapid redesign of superfolder mRNAs for B.1.351, P.1, and B.1.1.7 variants of the prefusion-stabilized SARS-CoV-2 spike protein. Increases in in vitro mRNA half-life by at least two-fold appear immediately achievable. Significance statementMessenger RNA (mRNA) medicines that encode and promote translation of a target protein have shown promising use as vaccines in the current SARS-CoV-2 pandemic as well as infectious diseases due to their speed of design and manufacturing. However, these molecules are intrinsically prone to hydrolysis, leading to poor stability in aqueous buffer and major challenges in distribution. Here, we present a principled biophysical model for predicting RNA degradation, and demonstrate that the stability of any mRNA can be increased at least two-fold over conventional design techniques. Furthermore, the predicted stabilization is robust to post-design modifications. This conceptual framework and accompanying algorithm can be immediately deployed to guide re-design of mRNA vaccines and therapeutics to increase in vitro stability.

biophysics↗

bioRxiv2020

An in-silico study on SARS-CoV-2: Its compatibility with human tRNA pool, and the polymorphism arising in a single lineage over a month

SARS-CoV-2 has caused a global pandemic that has costed enormous human lives in the recent past. The present study is an investigation of the viral codon adaptation, ORFs stability and tRNA co-adaptation with humans. We observed that for the codon usage bias in viral ssRNA, ORFs have near values of folding free energies and codon adaptation index with mRNAs of the human housekeeping CDS. However, the correlation between the stability of the ORFs in ssRNA and CAI is stronger than the mRNA stability and CAI of HKG, suggesting a greater expression capacity of SARS-CoV-2. Mutational analysis reflects polymorphism in the virus for ORF1ab, surface glycoprotein and nucleocapsid phosphoprotein ORFs. Non-synonymous mutations have shown non-polar substitutions. Out of the twelve mutations nine are for a higher t-RNA copy number. Viruses in general have high mutation rates. To understand the chances of survival for the mutated SARS-CoV-2 we did simulation for synonymous mutations. It resulted in 50% ORFs with higher stability than their native equivalents. Thus, considering only the synonymous mutations the virus can exhibit a lot of polymorphism. Collectively our data provides new insights for SARS-CoV-2 mutations and the human t-RNA compatibility. SignificanceSurvivability of SARS-CoV-2 in humans is essential for its spread. It has overlapping genes exhibiting a high codon optimization with humans even after a higher codon usage bias. They seem to possess cognizance for high copy number t-RNA (cognate or near-cognate) in humans, while mutating. Even though, it has been well established that native transcripts posses the highest stability, our in-silico studies show that SARS-CoV-2 under mutations give rise to ORFs with higher stability. These results significantly present the viruss ability and the credibility of survival for the mutants. Despite its focus on a geographical location it explains the ongoing behavior of SARS-CoV-2 for a steady existence in humans as all the different lineages have a common origin. Wuhan, China.

bioinformatics↗

bioRxiv2020

Cryo-electron Microscopy and Exploratory Antisense Targeting of the 28-kDa Frameshift Stimulation Element from the SARS-CoV-2 RNA Genome

Drug discovery campaigns against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) are beginning to target the viral RNA genome1, 2. The frameshift stimulation element (FSE) of the SARS-CoV-2 genome is required for balanced expression of essential viral proteins and is highly conserved, making it a potential candidate for antiviral targeting by small molecules and oligonucleotides3-6. To aid global efforts focusing on SARS-CoV-2 frameshifting, we report exploratory results from frameshifting and cellular replication experiments with locked nucleic acid (LNA) antisense oligonucleotides (ASOs), which support the FSE as a therapeutic target but highlight difficulties in achieving strong inactivation. To understand current limitations, we applied cryogenic electron microscopy (cryo-EM) and the Ribosolve7 pipeline to determine a three-dimensional structure of the SARS-CoV-2 FSE, validated through an RNA nanostructure tagging method. This is the smallest macromolecule (88 nt; 28 kDa) resolved by single-particle cryo-EM at subnanometer resolution to date. The tertiary structure model, defined to an estimated accuracy of 5.9 [A], presents a topologically complex fold in which the 5' end threads through a ring formed inside a three-stem pseudoknot. Our results suggest an updated model for SARS-CoV-2 frameshifting as well as binding sites that may be targeted by next generation ASOs and small molecules.

biochemistry↗

bioRxiv2020

Functional and structural basis of extreme non-coding conservation in vertebrate mRNA 5' untranslated regions

The lack of knowledge about extreme conservation in genomes remains a major gap in our understanding of the evolution of gene regulation. While previous findings have mainly focused on the role of extreme conservation at the level of DNA in transcriptional regulation, its implications for RNA biology remains largely unexplored. Here, we reveal an unexpected role of extremely conserved 5UTRs in translational regulation that is linked to the emergence of essential developmental features in vertebrate species. Endogenous deletion of conserved elements within these 5UTRs decreased gene expression at the post-transcriptional level. A large-scale reporter library of extremely conserved 5UTRs revealed the widespread presence of cis-regulatory elements that promote cell-type specific regulation of translation. As these elements function as RNA molecules, further understanding of their potential structures was essential. We therefore developed in-cell mutate-and-map (icM2), a novel methodology that maps RNA structure using high-throughput mutational analysis, previously impossible to perform inside cells. Using icM2, we determined that an extremely conserved 5UTR encodes multiple alternative structures whose relative proportions are actively maintained by ATP-dependent RNA helicases. We further show that each single nucleotide within the extremely conserved element maintains the balance of alternative structures important to control the dynamic range of protein expression. These results explain how extreme sequence conservation can lead to RNA-level biological functions encoded in the untranslated regions of vertebrate genomes.

genetics↗

bioRxiv2020

Stability of Begomoviral pathogenicity determinant βC1 is modulated by mutually antagonistic SUMOylation and SIM interactions

To successfully invade new hosts, to break host resistance as well as to move within and between plant cells, viruses and their satellites have evolved a coordinated network of protein interactions. {beta}C1 protein encoded by specific geminiviral satellites acts as a key pathogenicity determinant. {beta}C1 from diverse viruses undergo multiple post-translational modifications (PTMs) such as ubiquitination and phosphorylation. However, the relevance of these and other layers of PTMs in host-geminiviral interactions has not been fully understood. Here we identified the significance of a novel layer of PTMs in Synedrella yellow vein clearing virus (SyYVCV) encoded {beta}C1 protein having well conserved SUMOylation and SUMO-interacting motifs (SIMs). We observed that SyYVCV {beta}C1 undergoes SUMOylation in host plants as a defensive strategy against ubiquitin mediated degradation. On the contrary, SIMs encoded in {beta}C1 mediate degradation of {beta}C1. Both these PTMs are also essential for the function of {beta}C1 protein since SIM and SUMOylation motif mutants failed to promote pathogenicity and viral replication in vivo. In addition, SUMOylation in different motifs of {beta}C1 led to functionally distinct outcomes, regulating the stability and function of the {beta}C1 protein, as well as increased global SUMOylation of host proteins. Our results indicate the presence of a novel mechanism mediating a fine balance between defence and counter-defence in which a SIM site is competitively sought for degradation and as a counter defense, {beta}C1 undergoes SUMOylation to escape from its degradation. Summary Statement{beta}C1 viral protein has evolved counter-defensive strategies to perturb host protein degradation pathways

plant biology↗

bioRxiv2020

RNA secondary structure packages ranked and improved by high-throughput experiments

The computer-aided study and design of RNA molecules is increasingly prevalent across a range of disciplines, yet little is known about the accuracy of commonly used structure modeling packages in tasks sensitive to ensemble properties of RNA. Here, we demonstrate that the EternaBench dataset, a set of over 20,000 synthetic RNA constructs designed in iterative cycles on the RNA design platform Eterna, provides incisive discriminative power in evaluating current packages in ensemble-oriented structure prediction tasks. We find that CONTRAfold and RNAsoft, packages with parameters derived through statistical learning, achieve consistently higher accuracy than more widely used packages in their standard settings, which derive parameters primarily from thermodynamic experiments. Motivated by these results, we develop a multitask-learning-based model, EternaFold, which demonstrates improved performance that generalizes to diverse external datasets, including complete mRNAs and viral genomes probed in human cells and synthetic designs modeling mRNA vaccines.

biophysics↗