Comput Struct Biotechnol J. 2021 Jan 26;19:1127-1144. doi: 10.1016/j.csbj.2021.01.004. eCollection 2021.

ABSTRACT

Despite the scientific and economic importance of maize, little is known about its specialized metabolism. Here, five maize organs were profiled using different reversed-phase liquid chromatography-mass spectrometry methods. The resulting spectral metadata, combined with candidate substrate-product pair (CSPP) networks, allowed the structural characterization of 427 of the 5,420 profiled compounds, including phenylpropanoids, flavonoids, benzoxazinoids, and auxin-related compounds, among others. Only 75 of the 427 compounds were already described in maize. Analysis of the CSPP networks showed that phenylpropanoids are present in all organs, whereas other metabolic classes are rather organ-enriched. Frequently occurring CSPP mass differences often corresponded with glycosyl- and acyltransferase reactions. The interplay of glycosylations and acylations yields a wide variety of mixed glycosides, bearing substructures corresponding to the different biochemical classes. For example, in the tassel, many phenylpropanoid and flavonoid-bearing glycosides also contain auxin-derived moieties. The characterized compounds and mass differences are an important step forward in metabolic pathway discovery and systems biology research. The spectral metadata of the 5,420 compounds is publicly available (DynLib spectral database, https://bioit3.irc.ugent.be/dynlib/).

PMID:33680356 | PMC:PMC7890092 | DOI:10.1016/j.csbj.2021.01.004

Iran J Pharm Res. 2020 Summer;19(3):329-348. doi: 10.22037/ijpr.2020.112959.14040.

ABSTRACT

CTLA4-Ig (Abatacept) has been produced to suppress immune response by inhibition of T cells functions in autoimmune disease. A new drug, which is called belatacept, has recently been recently developed that is more efficient. The development has been occurred by two substitutions (A29Y, L104E) in the extracellular domain of CTLA4. In the present study, the bioinformatics analysis was used in order to make a new structure that has a better function in comparison with belatacept. Firstly, eight different structures were designed. Thereafter, the secondary and 3D structures, mRNA structure, docking of chimeric proteins with CD80/CD86, antigenicity and affinity of designed chimeric molecules were predicted. Based on the criteria, a new candidate molecule was selected and its gene synthesized. The gene was cloned and expressed in E. coli BL21 (DE3) successfully. The purified rCTLA4-Ig was analyzed by SDS-PAGE, western blotting, and ELISA. Circular dichroism analysis (CD analysis) was used for characterization of the rCTLA4-Ig. Affinity of rCTLA4-Ig was also evaluated by the flow cytometry method. Finally, its biological activity was determined by T cell inhibition test. The results showed rCTLA4-Ig and the belatacept protein have some similarities in structure and function. In addition, rCTLA4-Ig was able to bind CD80/CD86 and inhibit T cell function. Although flow cytomery results showed that the standard protein (CTLA4-Ig), represented better affinity than rCTLA4-Ig, the recombinant protein was able to inhibit T cell proliferation as well as CTLA4-Ig.

PMID:33680034 | PMC:PMC7757981 | DOI:10.22037/ijpr.2020.112959.14040

Iran J Pharm Res. 2020 Summer;19(3):321-328. doi: 10.22037/ijpr.2020.112966.14042.

ABSTRACT

The aim of the study was to evaluate the drug-resistance patterns of Staphylococcus aureus infections in Baqiyatallah hospital within 2010-2019 and to present a novel monitoring and detection system making use of molecular laboratory methods teamed with molecular delimitation analyses. This in turn is a primary step to establishment of a digital health system within Baqiyatallah hospital as a perfect pilot instance for other hospitals to follow upon. Totally, 100 patients of Baqiyatallah hospital suspicious of Staphylococcus aureus infections were sampled. Bacterial identity confirmations were done using routine biochemical test. Antibiograms were made for all the patients in this study. Consequently, bacterial total DNA was extracted and 16S rDNA gene amplified and sequenced for all patients. To uncover any cryptic strain grouping within the samples, a molecular delimitation method, i.e. automated barcode gap discovery (ABGD), was done. Our results showed Ceftaroline to be the most and Erythromycin and Oxacillin the least effective drugs. Delimitation uncovered 19 groups out of which group 19 seemed to have location-specific genetic signals in regards to susceptibility of Erythromycin and Oxacillin. Our results indicate the importance of genetic identification of bacteria with respect to their genetic patterns before antibiotic administration in order to both reduce unnecessary medicine use and to biomonitor the bacterial patterns in respect to their behavior towards general antibiotics.

PMID:33680033 | PMC:PMC7758007 | DOI:10.22037/ijpr.2020.112966.14042

Iran J Pharm Res. 2020 Summer;19(3):282-287. doi: 10.22037/ijpr.2020.1101148.

ABSTRACT

Resistance to antimicrobial compounds in E. coli strains is increasing. Integrons are mobile genetic elements that lead to the spread and transfer of antibiotic resistance genes in bacteria. The aim of the present study was to determine the frequency of class 1 and 2 integrons as well as the antimicrobial resistance in E.coli strains isolated from urinary tract infections (UTIs). A total of 100 clinical isolates of uropathogenic E. coli (UPEC) were collected from patients having UTIs. These strains were identified using biochemical tests. The antibiotic susceptibility patterns of the isolated bacteria were determined in accordance with the standard method recommended by the clinical and laboratory standards institute (CLSI). The presence of class 1 and 2 integrons was determined by PCR method. The most frequent antibiotic resistance was observed to ampicillin (72%), co-trimoxazole (66%), and nalidixic acid (62%). The highest sensitivity was seen to amikacine (11%) and gentamicin (20%). The multi-drug resistance (MDR) was observed in 80% of E. coli isolates. 70% and 3% of E. coli isolate possessed class 1 and 2 integrons, respectively. Our data suggest that the antimicrobial resistance to some antibiotics as well as the frequency of class 1 and 2 integrons is very high in E. coli strains. Moreover, class 1 integrons are correlated with resistance to ampicillin, gentamicin, ciprofloxacin, co-trimoxazole, and nalidixic acid. Therefore, it is very important to monitor integron-induced drug resistance, especially class 1 integron, in order to control the urinary tract infections causing by MDR E.coli strains.

PMID:33680029 | PMC:PMC7758018 | DOI:10.22037/ijpr.2020.1101148

Front Genet. 2021 Feb 18;12:624259. doi: 10.3389/fgene.2021.624259. eCollection 2021.

ABSTRACT

One aspect of personalized medicine is aiming at identifying specific targets for therapy considering the gene expression profile of each patient individually. The real-world implementation of this approach is better achieved by user-friendly bioinformatics systems for healthcare professionals. In this report, we present an online platform that endows users with an interface designed using MEAN stack supported by a Galaxy pipeline. This pipeline targets connection hubs in the subnetworks formed by the interactions between the proteins of genes that are up-regulated in tumors. This strategy has been proved to be suitable for the inhibition of tumor growth and metastasis in vitro. Therefore, Perl and Python scripts were enclosed in Galaxy for translating RNA-seq data into protein targets suitable for the chemotherapy of solid tumors. Consequently, we validated the process of target diagnosis by (i) reference to subnetwork entropy, (ii) the critical value of density probability of differential gene expression, and (iii) the inhibition of the most relevant targets according to TCGA and GDC data. Finally, the most relevant targets identified by the pipeline are stored in MongoDB and can be accessed through the aforementioned internet portal designed to be compatible with mobile or small devices through Angular libraries.

PMID:33679888 | PMC:PMC7935533 | DOI:10.3389/fgene.2021.624259

Front Plant Sci. 2021 Feb 10;12:629013. doi: 10.3389/fpls.2021.629013. eCollection 2021.

ABSTRACT

Network analysis is a systems biology-oriented approach based on graph theory that has been recently adopted in various fields of life sciences. Starting from mitochondrial proteomes purified from roots of Cucumis sativus plants grown under single or combined iron (Fe) and molybdenum (Mo) starvation, we reconstructed and analyzed at the topological level the protein-protein interaction (PPI) and co-expression networks. Besides formate dehydrogenase (FDH), already known to be involved in Fe and Mo nutrition, other potential mitochondrial hubs of Fe and Mo homeostasis could be identified, such as the voltage-dependent anion channel VDAC4, the beta-cyanoalanine synthase/cysteine synthase CYSC1, the aldehyde dehydrogenase ALDH2B7, and the fumaryl acetoacetate hydrolase. Network topological analysis, applied to plant proteomes profiled in different single or combined nutritional conditions, can therefore assist in identifying novel players involved in multiple homeostatic interactions.

PMID:33679842 | PMC:PMC7928335 | DOI:10.3389/fpls.2021.629013

Front Immunol. 2021 Feb 19;12:590532. doi: 10.3389/fimmu.2021.590532. eCollection 2021.

ABSTRACT

The liver is the central hub for processing and maintaining homeostatic levels of dietary nutrients especially essential amino acids such as tryptophan (Trp). Trp is required not only to sustain protein synthesis but also as a precursor for the production of NAD, neurotransmitters and immunosuppressive metabolites. In light of these roles of Trp and its metabolic products, maintaining homeostatic levels of Trp is essential for health and well-being. The liver regulates global Trp supply by the immunosuppressive enzyme tryptophan-2,3-dioxygenase (TDO2), which degrades Trp down the kynurenine pathway (KP). In the current study, we show that isolated primary hepatocytes when exposed to hypoxic environments, extensively rewire their Trp metabolism by reducing constitutive Tdo2 expression and differentially regulating other Trp pathway enzymes and transporters. Mathematical modelling of Trp metabolism in liver cells under hypoxia predicted decreased flux through the KP while metabolic flux through the tryptamine branch significantly increased. In line, the model also revealed an increased accumulation of tryptamines under hypoxia, at the expense of kynurenines. Metabolic measurements in hypoxic hepatocytes confirmed the predicted reduction in KP metabolites as well as accumulation of tryptamine. Tdo2 expression in cultured primary hepatocytes was reduced upon hypoxia inducible factor (HIF) stabilisation by dimethyloxalylglycine (DMOG), demonstrating that HIFs are involved in the hypoxic downregulation of hepatic Tdo2. DMOG abrogated hepatic luciferase signals in Tdo2 reporter mice, indicating that HIF stability also recapitulates hypoxic rewiring of Trp metabolism in vivo. Also in WT mice HIF stabilization drove homeostatic Trp metabolism away from the KP towards enhanced tryptamine production, leading to enhanced levels of tryptamine in liver, serum and brain. As tryptamines are the most potent hallucinogens known, the observed upregulation of tryptamine in response to hypoxic exposure of hepatocytes may be involved in the generation of hallucinations occurring at high altitude. KP metabolites are known to activate the aryl hydrocarbon receptor (AHR). The AHR-activating properties of tryptamines may explain why immunosuppressive AHR activity is maintained under hypoxia despite downregulation of the KP. In summary our results identify hypoxia as an important factor controlling Trp metabolism in the liver with possible implications for immunosuppressive AHR activation and mental disturbances.

PMID:33679737 | PMC:PMC7933006 | DOI:10.3389/fimmu.2021.590532

Semin Nephrol. 2020 Nov;40(6):586-599. doi: 10.1016/j.semnephrol.2020.12.002.

ABSTRACT

Increased urate levels and gout correlate with chronic kidney disease with consensus that the primary driver of this relationship is reduced kidney function. However, a comparison of results of genome-wide association studies in serum urate levels and kidney function indicate a more complex situation. Approximately 20% of loci are shared-comprised of those in which the urate-raising allele associates with reduced kidney function, the vice versa situation, and those in which the signals/alleles are different. Although there is very little known regarding the molecular basis of the shared genetic relationship, it is clear that there is no major role for urate transporters and associated transportasome machinery. Some loci, however, do provide clues. The ATXN2 locus, with a shared signal, is one of only a small number of master regulators of expression by chromatin interaction, regulating expression of genes relevant for cholesterol and blood pressure. This suggests a role for systemic metabolic alteration. At HNF4A there is genetic heterogeneity with different genetic variants conferring risk to hyperuricemia and chronic kidney disease, suggesting different pathways. Interestingly, the shared loci congregate in the olfactory receptor pathway. The genome-wide association studies have generated a range of experimentally testable hypotheses that should provide insights into the shared pathogenesis of hyperuricemia/gout and chronic kidney disease.

PMID:33678313 | DOI:10.1016/j.semnephrol.2020.12.002

J Allergy Clin Immunol. 2021 Mar;147(3):781-793. doi: 10.1016/j.jaci.2020.08.026.

ABSTRACT

In asthma, a significant portion of the interaction between genetics and environment occurs through microbiota. The proposed mechanisms behind this interaction are complex and at times contradictory. This review covers recent developments in our understanding of this interaction: the "microbial hypothesis" and the "farm effect"; the role of endotoxin and genetic variation in pattern recognition systems; the interaction with allergen exposure; the additional involvement of host gut and airway microbiota; the role of viral respiratory infections in interaction with the 17q21 and CDHR3 genetic loci; and the importance of in utero and early-life timing of exposures. We propose a unified framework for understanding how all these phenomena interact to drive asthma pathogenesis. Finally, we point out some future challenges for continued research in this field, in particular the need for multiomic integration, as well as the potential utility of asthma endotyping.

PMID:33678251 | DOI:10.1016/j.jaci.2020.08.026

Mol Biol Evol. 2021 Mar 2:msab061. doi: 10.1093/molbev/msab061. Online ahead of print.

ABSTRACT

Periods of nutrient shortage impose strong selection on animal populations. Experimental studies of genetic adaptation to nutrient shortage largely focus on resistance to acute starvation at adult stage; it is not clear how conclusions drawn from these studies extrapolate to other forms of nutritional stress. We studied the genomic signature of adaptation to chronic juvenile malnutrition in six populations of Drosophila melanogaster evolved for 150 generations on an extremely nutrient-poor larval diet. Comparison with control populations evolved on standard food revealed repeatable genomic differentiation between the two set of population, involving >3,000 candidate SNPs forming >100 independently evolving clusters. The candidate genomic regions were enriched in genes implicated in hormone, carbohydrate, and lipid metabolism, including some with known effects on fitness-related life-history traits. Rather than being close to fixation, a substantial fraction of candidate SNPs segregated at intermediate allele frequencies in all malnutrition-adapted populations. This, together with patterns of among-population variation in allele frequencies and estimates of Tajima's D, suggests that the poor diet results in balancing selection on some genomic regions. Our candidate genes for tolerance to larval malnutrition showed a high overlap with genes previously implicated in acute starvation resistance. However, adaptation to larval malnutrition in our study was associated with reduced tolerance to acute adult starvation. Thus, rather than reflecting synergy, the shared genomic architecture appears to mediate an evolutionary trade-off between tolerances to these two forms of nutritional stress.

PMID:33677563 | DOI:10.1093/molbev/msab061

Curr Opin Plant Biol. 2021 Mar 3;62:102011. doi: 10.1016/j.pbi.2021.102011. Online ahead of print.

ABSTRACT

The natural diversity of pathogen effectors and host immune components represents a snapshot of the underlying evolutionary processes driving the host-pathogen arms race. In plants, this arms race is manifested by an ongoing cycle of disease and resistance driven by pathogenic effectors that promote disease (effector-triggered susceptibility; ETS) and plant resistance proteins that recognize effector activity to trigger immunity (effector-triggered immunity; ETI). Here we discuss how this ongoing ETS-ETI cycle has shaped the natural diversity of both plant resistance proteins and pathogen effectors. We focus on the evolutionary forces that drive the diversification of the molecules that determine the outcome of plant-pathogen interactions and introduce the concept of metapopulation dynamics (i.e., the introduction of genetic variation from conspecific organisms in different populations) as an alternative mechanism that can introduce and maintain diversity in both host and pathogen populations.

PMID:33677388 | DOI:10.1016/j.pbi.2021.102011

Exp Hematol. 2021 Mar 4:S0301-472X(21)00093-X. doi: 10.1016/j.exphem.2021.02.011. Online ahead of print.

ABSTRACT

Polycythemia vera (PV) is a myeloproliferative neoplasm marked by hyperproliferation of the myeloid lineages and the presence of an activating JAK2 mutation. Hydroxyurea (HU) is a standard treatment for high-risk PV patients. Since disease-driving mechanisms are thought to arise in PV stem cells, effective treatments should primarily target the stem cell compartment. We tested for the anti-proliferative effect of patient treatment with HU in FACS-isolated hematopoietic stem/multipotent progenitor cells (HSC/MPPs) and more committed erythroid progenitors (CMP/MEPs) in PV using RNA-sequencing and gene set enrichment analysis. HU treatment led to significant downregulation of gene sets associated with cell proliferation in PV HSC/MPPs, but not in PV CMP/MEPs. To explore the mechanism underlying this finding, we assessed for expression of solute carrier membrane transporters, which mediate transmembrane movement of drugs like HU into target cells. The active HU uptake transporter OCTN1 was upregulated in HSC/MPPs compared to CMP/MEPs of untreated PV patients, and the HU diffusion facilitator UTB was downregulated in HSC/MPPs compared to CMP/MEPs in all tested patient and control groups. These findings indicate a higher accumulation of HU within PV HSC/MPPs compared to PV CMP/MEPs and provide an explanation for the differential effects of HU in HSC/MPPs and CMP/MEPs of PV patients. In general, the findings highlight the importance of transporter expression in linking therapeutics with human disease.

PMID:33677043 | DOI:10.1016/j.exphem.2021.02.011

Peptides. 2021 Mar 4:170526. doi: 10.1016/j.peptides.2021.170526. Online ahead of print.

ABSTRACT

The Coronaviridae family comprises large enveloped single-stranded RNA viruses. The known human-infecting coronaviruses; severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV), novel SARS-CoV-2, human coronavirus (HCoV)-NL63, HCoV-229E, HCoV-OC43 and HKU1 cause mild to severe respiratory infections. The viral diseases induced by mammalian and avian viruses from Coronaviridae family pose significant economic and public health burdens. Due to increasing reports of viral resistance, co-infections and the emergence of viral epidemics such as COVID-19, available antiviral drugs show low or no efficacy, and the production of new treatments or vaccines are also challenging. Therefore, demand for the development of novel antivirals has considerably increased. In recent years, antiviral peptides have generated increasing interest as they are from natural and computational sources, are highly specific and effective, and possess the broad-spectrum activity with minimum side effects. Here, we have made an effort to compile and review the antiviral peptides with activity against Coronaviridae family viruses. They were divided into different categories according to their action mechanisms, including binding/attachment inhibitors, fusion and entry inhibitors, viral enzyme inhibitors, replication inhibitors and the peptides with direct and indirect effects on the viruses. Reported studies suggest optimism with regard to the design and production of therapeutically promising antiviral drugs. This review aims to summarize data relating to antiviral peptides particularly with respect to their applicability for development as novel treatments.

PMID:33676968 | DOI:10.1016/j.peptides.2021.170526

Curr Opin Chem Biol. 2021 Feb;60:A1-A3. doi: 10.1016/j.cbpa.2021.02.006.

NO ABSTRACT

PMID:33676636 | DOI:10.1016/j.cbpa.2021.02.006

BMC Vet Res. 2021 Mar 6;17(1):112. doi: 10.1186/s12917-021-02815-y.

ABSTRACT

BACKGROUND: Dogs are domesticated wolves. Change of living environment, such as diet and veterinary care may affect the gut bacterial flora of dogs. The aim of this study was to assess the gut bacterial diversity and function in dogs compared with captive wolves. We surveyed the gut bacterial diversity of 27 domestic dogs, which were fed commercial dog food, and 31 wolves, which were fed uncooked meat, by 16S rRNA sequencing. In addition, we collected fecal samples from 5 dogs and 5 wolves for shotgun metagenomic sequencing to explore changes in the functions of their gut microbiome.

RESULTS: Differences in the abundance of core bacterial genera were observed between dogs and wolves. Together with shotgun metagenomics, the gut microbiome of dogs was found to be enriched in bacteria resistant to clinical drugs (P < 0.001), while wolves were enriched in bacteria resistant to antibiotics used in livestock (P < 0.001). In addition, a higher abundance of putative α-amylase genes (P < 0.05; P < 0.01) was observed in the dog samples.

CONCLUSIONS: Living environment of dogs and domestic wolves has led to increased numbers of bacteria with antibiotic resistance genes, with exposure to antibiotics through direct and indirect methods. In addition, the living environment of dogs has allowed the adaptation of their microbiota to a starch-rich diet. These observations align with a domestic lifestyle for domestic dogs and captive wolves, which might have consequences for public health.

PMID:33676490 | DOI:10.1186/s12917-021-02815-y

J Relig Health. 2021 Mar 6. doi: 10.1007/s10943-021-01192-y. Online ahead of print.

ABSTRACT

Today, the field of health is not limited to physical and mental health, but is related to all aspects of life, including spirituality. Spiritual health is so important that it is suggested as the fourth dimension of health, and in the near future, it will form part of the definition of health by the WHO. According to research in clinical psychology, in addition to spiritual health, another important issue in most psychotherapy theories is the issue of thinking. Given the importance of health and thinking, so far, no model has been presented in the field of the relationship between "thinking and health". So, the purpose of the present study is introducing a new model of healthy thinking based on human soul faculties. In this study, qualitative content analysis method has been used. Indicators of sensory and intellectual thinking have been noted within research results, which are the main components of the new model of thinking. In this type of thinking model, it is argued that all human beings have powers within them that can grow, which are referred to as the faculties of the soul. The level of thinking of individuals is determined by the level of each person's soul faculties. The lowest level is sensory perception and the highest level is intellectual perception. The more a person grows from the level of sensory thinking to the level of intellectual thinking, the sources of thought error decrease and the better the health of the thinking. Also, those who have a level of intellectual thinking have a higher level of spiritual health and the lifestyle of these people is health-oriented. This is a philosophical-psychological model in which indicators of sensory thinking and intellectual deviation have been extracted from theories and texts of psychology and philosophy. The results of this study can be used in psychotherapy because research has shown that thinking, especially healthy thinking, has a very effective role in mental health and a healthy lifestyle as well as treatment of disorders.

PMID:33675459 | DOI:10.1007/s10943-021-01192-y

Aging Cell. 2021 Mar 5:e13335. doi: 10.1111/acel.13335. Online ahead of print.

ABSTRACT

Brain ageing is characterised by a decline in neuronal function and associated cognitive deficits. There is increasing evidence that myelin disruption is an important factor that contributes to the age-related loss of brain plasticity and repair responses. In the brain, myelin is produced by oligodendrocytes, which are generated throughout life by oligodendrocyte progenitor cells (OPCs). Currently, a leading hypothesis points to ageing as a major reason for the ultimate breakdown of remyelination in Multiple Sclerosis (MS). However, an incomplete understanding of the cellular and molecular processes underlying brain ageing hinders the development of regenerative strategies. Here, our combined systems biology and neurobiological approach demonstrate that oligodendroglial and myelin genes are amongst the most altered in the ageing mouse cerebrum. This was underscored by the identification of causal links between signalling pathways and their downstream transcriptional networks that define oligodendroglial disruption in ageing. The results highlighted that the G-protein coupled receptor Gpr17 is central to the disruption of OPCs in ageing and this was confirmed by genetic fate-mapping and cellular analyses. Finally, we used systems biology strategies to identify therapeutic agents that rejuvenate OPCs and restore myelination in age-related neuropathological contexts.

PMID:33675110 | DOI:10.1111/acel.13335

Plant Cell Environ. 2021 Mar 5. doi: 10.1111/pce.14039. Online ahead of print.

ABSTRACT

Plants rely on their microbiota for improving the nutritional status and environmental stress tolerance. Previous studies mainly focused on bipartite interactions (a plant challenged by a single microbe), while plant responses to multiple microbes have received limited attention. Here, we investigated local and systemic changes induced in wheat by two plant growth-promoting bacteria (PGPB), Azospirillum brasilense and Paraburkholderia graminis, either alone or together with an arbuscular mycorrhizal fungus (AMF). We conducted phenotypic, proteomic, and biochemical analyses to investigate bipartite (wheat-PGPB) and tripartite (wheat-PGPB-AMF) interactions, also upon a leaf pathogen infection. Results revealed that only AMF and A. brasilense promoted plant growth by activating photosynthesis and N assimilation which led to increased glucose and amino acid content. The bioprotective effect of the PGPB-AMF interactions on infected wheat plants depended on the PGPB-AMF combinations, which caused specific phenotypic and proteomic responses (elicitation of defense related proteins, immune response, and jasmonic acid biosynthesis). In the whole, wheat responses strongly depended on the inoculum composition (single vs. multiple microbes) and the investigated organs (roots vs. leaf). Our findings showed that AMF is the best-performing microbe, suggesting its presence as the crucial one for synthetic microbial community development. This article is protected by copyright. All rights reserved.

PMID:33675052 | DOI:10.1111/pce.14039

Mol Biol Evol. 2021 Mar 1:msab060. doi: 10.1093/molbev/msab060. Online ahead of print.

ABSTRACT

SARS-CoV-2 infects humans through the binding of viral S-protein (spike protein) to human ACE2 (angiotensin I converting enzyme 2). The structure of the ACE2-S-protein complex has been deciphered and we focused on the 27 ACE2 residues that bind to S-protein. From human sequence databases, we identified 9 ACE2 variants at ACE2-S-protein binding sites. We used both experimental assays and protein structure analysis to evaluate the effect of each variant on the binding affinity of ACE2 to S-protein. We found one variant causing complete binding disruption, two and three variants, respectively, strongly and mildly reducing the binding affinity, and two variants strongly enhancing the binding affinity. We then collected the ACE2 gene sequences from 57 non-human primates. Among the six apes and 20 Old World monkeys (OWMs) studied we found no new variants. In contrast, all 11 New World monkeys (NWMs) studied share four variants each causing a strong reduction in binding affinity, the Philippine tarsier also possesses three such variants, and 18 of the 19 prosimian species studied share one variant causing a strong reduction in binding affinity. Moreover, one OWM and three prosimian variants increased binding affinity by > 50%. Based on these findings we proposed that the common ancestor of primates was strongly resistant to and that of NWMs was completely resistant to SARS-CoV-2 and so is the Philippine tarsier, whereas apes and OWMs, like most humans, are susceptible. This study increases our understanding of the differences in susceptibility to SARS-CoV-2 infection among primates.

PMID:33674876 | DOI:10.1093/molbev/msab060

Cell Res. 2021 Mar 5. doi: 10.1038/s41422-021-00472-2. Online ahead of print.

ABSTRACT

RNA polymerase III (Pol III) transcribes essential structured small RNAs, such as tRNAs, 5S rRNA and U6 snRNA. The transcriptional activity of Pol III is tightly controlled and its dysregulation is associated with human diseases, such as cancer. Human Pol III has two isoforms with difference only in one of its subunits RPC7 (α and β). Despite structural studies of yeast Pol III, structure of human Pol III remains unsolved. Here, we determined the structures of 17-subunit human Pol IIIα complex in the backtracked and post-translocation states, respectively. Human Pol III contains a generally conserved catalytic core, similar to that of yeast counterpart, and structurally unique RPC3-RPC6-RPC7 heterotrimer and RPC10. The N-ribbon of TFIIS-like RPC10 docks on the RPC4-RPC5 heterodimer and the C-ribbon inserts into the funnel of Pol III in the backtracked state but is more flexible in the post-translocation state. RPC7 threads through the heterotrimer and bridges the stalk and Pol III core module. The winged helix 1 domain of RPC6 and the N-terminal region of RPC7α stabilize each other and may prevent Maf1-mediated repression of Pol III activity. The C-terminal FeS cluster of RPC6 coordinates a network of interactions that mediate core-heterotrimer contacts and stabilize Pol III. Our structural analysis sheds new light on the molecular mechanism of human Pol IIIα-specific transcriptional regulation and provides explanations for upregulated Pol III activity in RPC7α-dominant cancer cells.

PMID:33674783 | DOI:10.1038/s41422-021-00472-2