Systems Biology
Toward a universal measure of robustness across model organs and systems
Evol Dev. 2023 Apr 18. doi: 10.1111/ede.12436. Online ahead of print.
ABSTRACT
The development of an individual must be capable of resisting the harmful effects of internal and external perturbations. This capacity, called robustness, can make the difference between normal variation and disease. Some systems and organs are more resilient in their capacity to correct the effects of internal disturbances such as mutations. Similarly, organs and organisms differ in their capacity to be resilient against external disturbances, such as changes in temperature. Furthermore, all developmental systems must be somewhat flexible to permit evolutionary change, and understanding robustness requires a comparative framework. Over the last decades, most research on developmental robustness has been focusing on specific model systems and organs. Hence, we lack tools that would allow cross-species and cross-organ comparisons. Here, we emphasize the need for a uniform framework to experimentally test and quantify robustness across study systems and suggest that the analysis of fluctuating asymmetry might be a powerful proxy to do so. Such a comparative framework will ultimately help to resolve why and how organs of the same and different species differ in their sensitivity to internal (e.g., mutations) and external (e.g., temperature) perturbations and at what level of biological organization buffering capacities exist and therefore create robustness of the developmental system.
PMID:37070415 | DOI:10.1111/ede.12436
RNA-dependent interactome allows network-based assignment of RNA-binding protein function
Nucleic Acids Res. 2023 Apr 18:gkad245. doi: 10.1093/nar/gkad245. Online ahead of print.
ABSTRACT
RNA-binding proteins (RBPs) form highly diverse and dynamic ribonucleoprotein complexes, whose functions determine the molecular fate of the bound RNA. In the model organism Sacchromyces cerevisiae, the number of proteins identified as RBPs has greatly increased over the last decade. However, the cellular function of most of these novel RBPs remains largely unexplored. We used mass spectrometry-based quantitative proteomics to systematically identify protein-protein interactions (PPIs) and RNA-dependent interactions (RDIs) to create a novel dataset for 40 RBPs that are associated with the mRNA life cycle. Domain, functional and pathway enrichment analyses revealed an over-representation of RNA functionalities among the enriched interactors. Using our extensive PPI and RDI networks, we revealed putative new members of RNA-associated pathways, and highlighted potential new roles for several RBPs. Our RBP interactome resource is available through an online interactive platform as a community tool to guide further in-depth functional studies and RBP network analysis (https://www.butterlab.org/RINE).
PMID:37070168 | DOI:10.1093/nar/gkad245
Deciphering molecular mechanisms of SARS-CoV-2 pathogenesis and drug repurposing through GRN motifs: a comprehensive systems biology study
3 Biotech. 2023 Apr;13(4):117. doi: 10.1007/s13205-023-03518-x. Epub 2023 Mar 13.
ABSTRACT
The world has recently been plagued by a new coronavirus infection called SARS-CoV-2. This virus may lead to severe acute respiratory syndrome followed by multiple organ failure. SARS-CoV-2 has approximately 80-90% genetic similarity to SARS-CoV. Given the limited omics data available for host response to the viruses (more limited data for SARS-CoV-2), we attempted to unveil the crucial molecular mechanisms underlying the SARS-CoV-2 pathogenesis by comparing its regulatory network motifs with SARS-CoV. We also attempted to identify the non-shared crucial molecules and their functions to predict the specific mechanisms for each infection and the processes responsible for their different manifestations. Deciphering the crucial shared and non-shared mechanisms at the molecular level and signaling pathways underlying both diseases may help shed light on their pathogenesis and pave the way for other new drug repurposing against COVID-19. We constructed the GRNs for host response to SARS-CoV and SARS-CoV-2 pathogens (in vitro) and identified the significant 3-node regulatory motifs by analyzing them topologically and functionally. We attempted to identify the shared and non-shared regulatory elements and signaling pathways between their host responses. Interestingly, our findings indicated that NFKB1, JUN, STAT1, FOS, KLF4, and EGR1 were the critical shared TFs between motif-related subnetworks in both SARS and COVID-1, which are considered genes with specific functions in the immune response. Enrichment analysis revealed that the NOD-like receptor signaling, TNF signaling, and influenza A pathway were among the first significant pathways shared between SARS and COVID-19 up-regulated DEGs networks, and the term "metabolic pathways" (hsa01100) among the down-regulated DEGs networks. WEE1, PMAIP1, and TSC22D2 were identified as the top three hubs specific to SARS. However, MYPN, SPRY4, and APOL6 were the tops specific to COVID-19 in vitro. The term "Complement and coagulation cascades" pathway was identified as the first top non-shared pathway for COVID-19 and the MAPK signaling pathway for SARS. We used the identified crucial DEGs to construct a drug-gene interaction network to propose some drug candidates. Zinc chloride, Fostamatinib, Copper, Tirofiban, Tretinoin, and Levocarnitine were the six drugs with higher scores in our drug-gene network analysis.
SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-023-03518-x.
PMID:37070032 | PMC:PMC10090260 | DOI:10.1007/s13205-023-03518-x
Three tyrosine kinase inhibitors cause cardiotoxicity by inducing endoplasmic reticulum stress and inflammation in cardiomyocytes
BMC Med. 2023 Apr 17;21(1):147. doi: 10.1186/s12916-023-02838-2.
ABSTRACT
BACKGROUND: Tyrosine kinase inhibitors (TKIs) are anti-cancer therapeutics often prescribed for long-term treatment. Many of these treatments cause cardiotoxicity with limited cure. We aim to clarify molecular mechanisms of TKI-induced cardiotoxicity so as to find potential targets for treating the adverse cardiac complications.
METHODS: Eight TKIs with different levels of cardiotoxicity reported are selected. Phenotypic and transcriptomic responses of human cardiomyocytes to TKIs at varying doses and times are profiled and analyzed. Stress responses and signaling pathways that modulate cardiotoxicity induced by three TKIs are validated in cardiomyocytes and rat hearts.
RESULTS: Toxicity rank of the eight TKIs determined by measuring their effects on cell viability, contractility, and respiration is largely consistent with that derived from database or literature, indicating that human cardiomyocytes are a good cellular model for studying cardiotoxicity. When transcriptomes are measured for selected TKI treatments with different levels of toxicity in human cardiomyocytes, the data are classified into 7 clusters with mainly single-drug clusters. Drug-specific effects on the transcriptome dominate over dose-, time- or toxicity-dependent effects. Two clusters with three TKIs (afatinib, ponatinib, and sorafenib) have the top enriched pathway as the endoplasmic reticulum stress (ERS). All three TKIs induce ERS in rat primary cardiomyocytes and ponatinib activates the IRE1α-XBP1s axis downstream of ERS in the hearts of rats underwent a 7-day course of drug treatment. To look for potential triggers of ERS, we find that the three TKIs induce transient reactive oxygen species followed by lipid peroxidation. Inhibiting either PERK or IRE1α downstream of ERS blocks TKI-induced cardiac damages, represented by the induction of cardiac fetal and pro-inflammatory genes without causing more cell death.
CONCLUSIONS: Our data contain rich information about phenotypic and transcriptional responses of human cardiomyocytes to eight TKIs, uncovering potential molecular mechanisms in modulating cardiotoxicity. ER stress is activated by multiple TKIs and leads to cardiotoxicity through promoting expression of pro-inflammatory factors and cardiac fetal genes. ER stress-induced inflammation is a promising therapeutic target to mitigate ponatinib- and sorafenib-induced cardiotoxicity.
PMID:37069550 | DOI:10.1186/s12916-023-02838-2
Application of sequence semantic and integrated cellular geography approach to study alternative biogenesis of exonic circular RNA
BMC Bioinformatics. 2023 Apr 17;24(1):148. doi: 10.1186/s12859-023-05279-z.
ABSTRACT
BACKGROUND: Concurrent existence of lncRNA and circular RNA at both nucleus and cytosol within a cell at different proportions is well reported. Previous studies showed that circular RNAs are synthesized in nucleus followed by transportation across the nuclear membrane and the export is primarily defined by their length. lncRNAs primarily originated through inefficient splicing and seem to use NXF1 for cytoplasm export. However, it is not clear whether circularization of lncRNA happens only in nucleus or it also occurs in cytoplasm. Studies indicate that circular RNAs arise when the splicing apparatus undergoes a phenomenon of back splicing. Minor spliceosome (U12 type) mediated splicing occurs in cytoplasm and is responsible for the splicing of 0.5% of introns of human cells. Therefore, possibility of cRNA biogenesis mediated by minor spliceosome at cytoplasm cannot be ruled out. Secondly, information on genes transcribing both circular and lncRNAs along with total number of RBP binding sites for both of these RNA types is extractable from databases. This study showed how these apparently unconnected pieces of reports could be put together to build a model for exploring biogenesis of circular RNA.
RESULTS: As a result of this study, a model was built under the premises that, sequences with special semantics were molecular precursors in biogenesis of circular RNA which occurred through catalytic role of some specific RBPs. The model outcome was further strengthened by fulfillment of three logical lemmas which were extracted and assimilated in this work using a novel data analytic approach, Integrated Cellular Geography. Result of the study was found to be in well agreement with proposed model. Furthermore this study also indicated that biogenesis of circular RNA was a post-transcriptional event.
CONCLUSIONS: Overall, this study provides a novel systems biology based model under the paradigm of Integrated Cellular Geography which can assimilate independently performed experimental results and data published by global researchers on RNA biology to provide important information on biogenesis of circular RNAs considering lncRNAs as precursor molecule. This study also suggests the possible RBP-mediated circularization of RNA in the cytoplasm through back-splicing using minor spliceosome.
PMID:37069509 | DOI:10.1186/s12859-023-05279-z
The proteomic landscape of genome-wide genetic perturbations
Cell. 2023 Apr 17:S0092-8674(23)00300-8. doi: 10.1016/j.cell.2023.03.026. Online ahead of print.
ABSTRACT
Functional genomic strategies have become fundamental for annotating gene function and regulatory networks. Here, we combined functional genomics with proteomics by quantifying protein abundances in a genome-scale knockout library in Saccharomyces cerevisiae, using data-independent acquisition mass spectrometry. We find that global protein expression is driven by a complex interplay of (1) general biological properties, including translation rate, protein turnover, the formation of protein complexes, growth rate, and genome architecture, followed by (2) functional properties, such as the connectivity of a protein in genetic, metabolic, and physical interaction networks. Moreover, we show that functional proteomics complements current gene annotation strategies through the assessment of proteome profile similarity, protein covariation, and reverse proteome profiling. Thus, our study reveals principles that govern protein expression and provides a genome-spanning resource for functional annotation.
PMID:37080200 | DOI:10.1016/j.cell.2023.03.026
Leveraging glycoside-targeted metabolomics to gain insight into biological function
Trends Plant Sci. 2023 Apr 17:S1360-1385(23)00130-9. doi: 10.1016/j.tplants.2023.04.004. Online ahead of print.
ABSTRACT
In plants, uridine diphosphate (UDP)-dependent glycosyltransferases (UGTs) catalyze glycosylation of secondary metabolites, but assigning physiological functions to UGTs is still a daunting task. The recent study of Wu et al. presents a useful method to resolve this problem by elegantly combining modification-specific metabolomics with isotope tracing.
PMID:37076401 | DOI:10.1016/j.tplants.2023.04.004
Inflammaging: mechanisms and role in the cardiac and vasculature
Trends Endocrinol Metab. 2023 Apr 17:S1043-2760(23)00057-7. doi: 10.1016/j.tem.2023.03.005. Online ahead of print.
ABSTRACT
Aging triggers a wide range of cellular and molecular aberrations in the body, giving rise to inflammation and associated diseases. In particular, aging is associated with persistent low-grade inflammation even in absence of inflammatory stimuli, a phenomenon commonly referred to as 'inflammaging'. Accumulating evidence has revealed that inflammaging in vascular and cardiac tissues is associated with the emergence of pathological states such as atherosclerosis and hypertension. In this review we survey molecular and pathological mechanisms of inflammaging in vascular and cardiac aging to identify potential targets, natural therapeutic compounds, and other strategies to suppress inflammaging in the heart and vasculature, as well as in associated diseases such as atherosclerosis and hypertension.
PMID:37076375 | DOI:10.1016/j.tem.2023.03.005
Functional genomics and systems biology of Cordyceps species for biotechnological applications
Curr Opin Biotechnol. 2023 Apr 17;81:102939. doi: 10.1016/j.copbio.2023.102939. Online ahead of print.
ABSTRACT
The use of Cordyceps species for the manufacture of natural products has been established; however, the tremendous advances observed in recent years in genetic engineering and molecular biology have revolutionized the optimization of Cordyceps as cell factories and drastically expanded the biotechnological potential of these fungi. Here, we present a review of systems and synthetic biology studies of Cordyceps and their implications for fungal biology and industrial applications. We summarize the current status of synthetic biology for enhancing targeted metabolites in Cordyceps species, such as cordycepin, adenosine, polysaccharide, and pentostatin. Progress in the systems and synthetic biology of Cordyceps provides a strategy for comprehensively comprehensive controlling efficient cell factories of natural bioproducts and novel synthetic biology toolbox for targeted engineering.
PMID:37075529 | DOI:10.1016/j.copbio.2023.102939
Ether phospholipids are required for mitochondrial reactive oxygen species homeostasis
Nat Commun. 2023 Apr 17;14(1):2194. doi: 10.1038/s41467-023-37924-9.
ABSTRACT
Mitochondria are hubs where bioenergetics, redox homeostasis, and anabolic metabolism pathways integrate through a tightly coordinated flux of metabolites. The contributions of mitochondrial metabolism to tumor growth and therapy resistance are evident, but drugs targeting mitochondrial metabolism have repeatedly failed in the clinic. Our study in pancreatic ductal adenocarcinoma (PDAC) finds that cellular and mitochondrial lipid composition influence cancer cell sensitivity to pharmacological inhibition of electron transport chain complex I. Profiling of patient-derived PDAC models revealed that monounsaturated fatty acids (MUFAs) and MUFA-linked ether phospholipids play a critical role in maintaining ROS homeostasis. We show that ether phospholipids support mitochondrial supercomplex assembly and ROS production; accordingly, blocking de novo ether phospholipid biosynthesis sensitized PDAC cells to complex I inhibition by inducing mitochondrial ROS and lipid peroxidation. These data identify ether phospholipids as a regulator of mitochondrial redox control that contributes to the sensitivity of PDAC cells to complex I inhibition.
PMID:37069167 | DOI:10.1038/s41467-023-37924-9
Chromosome-level genome assembly and population genomic resource to accelerate orphan crop lablab breeding
Nat Commun. 2023 Apr 17;14(1):1915. doi: 10.1038/s41467-023-37489-7.
ABSTRACT
Under-utilised orphan crops hold the key to diversified and climate-resilient food systems. Here, we report on orphan crop genomics using the case of Lablab purpureus (L.) Sweet (lablab) - a legume native to Africa and cultivated throughout the tropics for food and forage. Our Africa-led plant genome collaboration produces a high-quality chromosome-scale assembly of the lablab genome. Our assembly highlights the genome organisation of the trypsin inhibitor genes - an important anti-nutritional factor in lablab. We also re-sequence cultivated and wild lablab accessions from Africa confirming two domestication events. Finally, we examine the genetic and phenotypic diversity in a comprehensive lablab germplasm collection and identify genomic loci underlying variation of important agronomic traits in lablab. The genomic data generated here provide a valuable resource for lablab improvement. Our inclusive collaborative approach also presents an example that can be explored by other researchers sequencing indigenous crops, particularly from low and middle-income countries (LMIC).
PMID:37069152 | DOI:10.1038/s41467-023-37489-7
N6-methyladenosine-mediated gene regulation and therapeutic implications
Trends Mol Med. 2023 Apr 15:S1471-4914(23)00065-5. doi: 10.1016/j.molmed.2023.03.005. Online ahead of print.
ABSTRACT
N6-methyladenosine (m6A) RNA methylation is the most abundant form of mRNA modification in eukaryotes and is at the front line of biological and biomedical research. This dynamic and reversible m6A RNA modification determines the fates of modified RNA molecules at the post-transcriptional level, affecting almost all important biological processes. Notably, m6A is also involved in chromatin and transcriptional regulation, while m6A dysregulation is implicated in various diseases. Here, we review current knowledge of post-transcriptional and transcriptional regulatory mechanisms involving m6A modification. We also discuss their involvement in the occurrence and development of diseases, including cancer, as well as potential theranostic targets, in hope of facilitating the translation of preclinical findings to the clinic.
PMID:37068987 | DOI:10.1016/j.molmed.2023.03.005
A deep learning-based system trained for gastrointestinal stromal tumor screening can identify multiple types of soft tissue tumors
Am J Pathol. 2023 Apr 15:S0002-9440(23)00128-1. doi: 10.1016/j.ajpath.2023.03.012. Online ahead of print.
ABSTRACT
The accuracy and timeliness of the pathological diagnosis of soft tissue tumors (STTs) critically affect treatment decision and patient prognosis. Thus, it is crucial to make a preliminary judgement on whether the tumor is benign or malignant with hematoxylin-and-eosin (H&E)-stained images. Here, we present a deep learning-based system, STT-BOX, with only H&E images for malignant STTs identification from benign STTs with histopathological similarity. STT-BOX assumed gastrointestinal stromal tumor (GIST) as a baseline for malignant STT evaluation, and distinguished GIST from leiomyoma and Schwannoma with 100% AUC in patients from three hospitals, which achieved higher accuracy than the interpretation of experienced pathologists. Particularly, this system performed well on six common types of malignant STTs from TCGA dataset, accurately highlighting the malignant mass lesion. Moreover, without any fine-tuning, STT-BOX was capable to distinguish ovarian malignant sex-cord stromal tumors. Our study includes mesenchymal tumors originated from the digestive system, bone and soft tissues, and reproductive system, where the high accuracy of migration verification may reveal the morphological similarity of the nine types of malignant tumors. Further evaluation in a pan-STT setting would be potential and prospective, obviating the overuse of immunohistochemistry and molecular tests, and providing a practical basis for clinical treatment selection in a timely manner.
PMID:37068638 | DOI:10.1016/j.ajpath.2023.03.012
METTL3-Mediated m6A Modification Controls Splicing Factor Abundance and Contributes to Aggressive CLL
Blood Cancer Discov. 2023 Apr 17:OF1-OF18. doi: 10.1158/2643-3230.BCD-22-0156. Online ahead of print.
ABSTRACT
RNA splicing dysregulation underlies the onset and progression of cancers. In chronic lymphocytic leukemia (CLL), spliceosome mutations leading to aberrant splicing occur in ∼20% of patients. However, the mechanism for splicing defects in spliceosome-unmutated CLL cases remains elusive. Through an integrative transcriptomic and proteomic analysis, we discover that proteins involved in RNA splicing are posttranscriptionally upregulated in CLL cells, resulting in splicing dysregulation. The abundance of splicing complexes is an independent risk factor for poor prognosis. Moreover, increased splicing factor expression is highly correlated with the abundance of METTL3, an RNA methyltransferase that deposits N6-methyladenosine (m6A) on mRNA. METTL3 is essential for cell growth in vitro and in vivo and controls splicing factor protein expression in a methyltransferase-dependent manner through m6A modification-mediated ribosome recycling and decoding. Our results uncover METTL3-mediated m6A modification as a novel regulatory axis in driving splicing dysregulation and contributing to aggressive CLL.
SIGNIFICANCE: METTL3 controls widespread splicing factor abundance via translational control of m6A-modified mRNA, contributes to RNA splicing dysregulation and disease progression in CLL, and serves as a potential therapeutic target in aggressive CLL. See related commentary by Janin and Esteller.
PMID:37067905 | DOI:10.1158/2643-3230.BCD-22-0156
Li-Fraumeni Syndrome-Associated Dimer-Forming Mutant p53 Promotes Transactivation-Independent Mitochondrial Cell Death
Cancer Discov. 2023 Apr 17:OF1-OF24. doi: 10.1158/2159-8290.CD-22-0882. Online ahead of print.
ABSTRACT
Cancer-relevant mutations in the oligomerization domain (OD) of the p53 tumor suppressor protein, unlike those in the DNA binding domain, have not been well elucidated. Here, we characterized the germline OD mutant p53(A347D), which occurs in cancer-prone Li-Fraumeni syndrome (LFS) patients. Unlike wild-type p53, mutant p53(A347D) cannot form tetramers and exists as a hyperstable dimeric protein. Further, p53(A347D) cannot bind or transactivate the majority of canonical p53 target genes. Isogenic cell lines harboring either p53(A347D) or no p53 yield comparable tumorigenic properties, yet p53(A347D) displays remarkable neomorphic activities. Cells bearing p53(A347D) possess a distinct transcriptional profile and undergo metabolic reprogramming. Further, p53(A347D) induces striking mitochondrial network aberration and associates with mitochondria to drive apoptotic cell death upon topoisomerase II inhibition in the absence of transcription. Thus, dimer-forming p53 demonstrates both loss-of-function (LOF) and gain-of-function (GOF) properties compared with the wild-type form of the protein.
SIGNIFICANCE: A mutant p53 (A347D), which can only form dimers, is associated with increased cancer susceptibility in LFS individuals. We found that this mutant wields a double-edged sword, driving tumorigenesis through LOF while gaining enhanced apoptogenic activity as a new GOF, thereby yielding a potential vulnerability to select therapeutic approaches.
PMID:37067901 | DOI:10.1158/2159-8290.CD-22-0882
Emergent regulation of ant foraging frequency through a computationally inexpensive forager movement rule
Elife. 2023 Apr 17;12:e77659. doi: 10.7554/eLife.77659.
ABSTRACT
Ant colonies regulate foraging in response to their collective hunger, yet the mechanism behind this distributed regulation remains unclear. Previously, by imaging food flow within ant colonies we showed that the frequency of foraging events declines linearly with colony satiation (Greenwald et al., 2018). Our analysis implied that as a forager distributes food in the nest, two factors affect her decision to exit for another foraging trip: her current food load and its rate of change. Sensing these variables can be attributed to the forager's individual cognitive ability. Here, new analyses of the foragers' trajectories within the nest imply a different way to achieve the observed regulation. Instead of an explicit decision to exit, foragers merely tend toward the depth of the nest when their food load is high and toward the nest exit when it is low. Thus, the colony shapes the forager's trajectory by controlling her unloading rate, while she senses only her current food load. Using an agent-based model and mathematical analysis, we show that this simple mechanism robustly yields emergent regulation of foraging frequency. These findings demonstrate how the embedding of individuals in physical space can reduce their cognitive demands without compromising their computational role in the group.
PMID:37067884 | DOI:10.7554/eLife.77659
A systems biology-based approach to screen key splicing factors in hepatocellular carcinoma
Mol Carcinog. 2023 Apr 17. doi: 10.1002/mc.23549. Online ahead of print.
ABSTRACT
A splicing factor is as an important upstream regulator of the alternative splicing process. Hence, it is considered to be a therapeutic target for hepatocellular carcinoma (HCC) tissues. In this study, a systems biology-based methodology was used to screen the essential splicing factors precisely and efficiently. A more comprehensive set of alternative splicing events, which were linked to patient survival, was constructed by performing the bivariate Cox regression and receiver operating characteristic (ROC) analyses. Then, the expression data was obtained from The Cancer Genome Altas (TCGA) data set and the three Gene Expression Omnibus (GEO) datasets. It was used to obtain the survival-related splicing factors, which showed a significantly differential expression in the tumor and normal tissues. Using the topological properties of the bipartite graph association network of the alternative splicing events and the splicing factors, we identified the five key splicing factors. Among them, four factors were found to play a prominent role in the development of HCC. The remaining factor was Survival Motor Neuron Domain Containing 1(SMNDC1), which showed a positive correlation with the immune cell infiltration, the biomarkers of immune cells, and the immune checkpoint genes. By performing quantitative real-time polymerase chain reaction analyses, we proved that SMNDC1 was overexpressed in tumor cells. Following the knockdown of its expression, the proliferation and the migration of HCC cells could be suppressed. These results confirmed that the screening method of this study was reliable and accurate. It provided new insights into the mechanism through which splicing factors elicit tumor development.
PMID:37067402 | DOI:10.1002/mc.23549
Facilitation of axonal transcriptome analysis with quantitative microfluidic devices
Lab Chip. 2023 Apr 17. doi: 10.1039/d2lc01183b. Online ahead of print.
ABSTRACT
Microfluidic chambers are powerful tools for studying axonal mRNA localization and translation in neurons. In addition to specific manipulation and measurements of axons, microfluidic chambers are used for collecting axonal materials to perform axonal transcriptome analysis. However, traditional bipartite and tripartite chambers have limitations either in purity or quantity of collected axons. Here, we improved the design of traditional chambers. Moreover, we developed two new quantitative chambers, multi-compartmental quantitative bipartite chamber (MQBC) and long quantitative tripartite chamber (LQTC). Compared with the traditional chambers, MQBC and LQTC could dramatically increase the efficiency in collecting axonal RNA. Finally, we applied these chambers to do comparative axon transcriptome analysis of different types of neurons. Thus, our newly designed quantitative chambers significantly improve axon collection efficiency and facilitate axonal transcriptome analysis.
PMID:37067243 | DOI:10.1039/d2lc01183b
Engineering a Carboxyl Methyltransferase for the Formation of a Furan-Based Bioplastic Precursor
ChemSusChem. 2023 Apr 17:e202300516. doi: 10.1002/cssc.202300516. Online ahead of print.
ABSTRACT
FtpM from Aspergillus fumigatus was the first carboxyl methyltransferase reported to catalyse the dimethylation of dicarboxylic acids. Here we report the creation of mutant R166M that can catalyse the quantitative conversion of bio-derived 2,5-furandicarboxylic acid (FDCA) to its dimethyl ester (FDME), a bioplastics precursor. Wild type FtpM gave low conversion due to its reduced catalytic efficiency for the second methylation step. An AlphaFold 2 model revealed a highly electropositive active site, due to the presence of 4 arginine residues, postulated to favour the binding of the dicarboxylic acid over the intermediate monoester. The R166M mutation improved both binding and turnover of the monoester to permit near quantitative conversion to the target dimethyl ester product. The mutant also had improved activity for other diacids and a range of monacids. R166M was incorporated into 2 multienzyme cascades for the synthesis of the bioplastics precursor FDME from bioderived 5-hydroxymethylfurfural (HMF) as well as from poly(ethylene furanoate) (PEF) plastic, demonstrating the potential to recycle waste plastic.
PMID:37067062 | DOI:10.1002/cssc.202300516
The evolution and structure of snake venom phosphodiesterase (svPDE) highlight its importance in venom actions
Elife. 2023 Apr 17;12:e83966. doi: 10.7554/eLife.83966. Online ahead of print.
ABSTRACT
For decades, studies of snake venoms focused on the venom-ome-specific toxins (VSTs). VSTs are dominant soluble proteins believed to contribute to the main venomous effects and emerged into gene clusters for fast adaptation and diversification of snake venoms. However, the conserved minor venom components, such as snake venom phosphodiesterase (svPDE), remain largely unexplored. Here, we focus on svPDE by genomic and transcriptomic analysis across snake clades and demonstrate that soluble svPDE is co-opted from the ancestral membrane-attached ENPP3 (ectonucleotide pyrophosphatase/phosphodiesterase 3) gene by replacing the original 5' exon with the exon encoding a signal peptide. Notably, the exons, promoters and transcription/translation starts have been replaced multiple times during snake evolution, suggesting the evolutionary necessity of svPDE. The structural and biochemical analyses also show that svPDE shares the similar functions with ENPP family, suggesting its perturbation to the purinergic signaling and insulin transduction in venomous effects.
PMID:37067034 | DOI:10.7554/eLife.83966