Systems Biology
Role of the histone variant H2A.Z.1 in memory, transcription, and alternative splicing is mediated by lysine modification
Neuropsychopharmacology. 2024 Feb 16. doi: 10.1038/s41386-024-01817-2. Online ahead of print.
ABSTRACT
Creating long-lasting memories requires learning-induced changes in gene expression, which are impacted by epigenetic modifications of DNA and associated histone proteins. Post-translational modifications (PTMs) of histones are key regulators of transcription, with different PTMs producing unique effects on gene activity and behavior. Although recent studies implicate histone variants as novel regulators of memory, effects of PTMs on the function of histone variants are rarely considered. We previously showed that the histone variant H2A.Z suppresses memory, but it is unclear if this role is impacted by H2A.Z acetylation, a PTM that is typically associated with positive effects on transcription and memory. To answer this question, we used a mutation approach to manipulate acetylation on H2A.Z without impacting acetylation of other histone types. Specifically, we used adeno-associated virus (AAV) constructs to overexpress mutated H2A.Z.1 isoforms that either mimic acetylation (acetyl-mimic) by replacing lysines 4, 7 and 11 with glutamine (KQ), or H2A.Z.1 with impaired acetylation (acetyl-defective) by replacing the same lysines with alanine (KA). Expressing the H2A.Z.1 acetyl-mimic (H2A.Z.1KQ) improved memory under weak learning conditions, whereas expressing the acetyl-defective H2A.Z.1KA generally impaired memory, indicating that the effect of H2A.Z.1 on memory depends on its acetylation status. RNA sequencing showed that H2A.Z.1KQ and H2A.Z.1KA uniquely impact the expression of different classes of genes in both females and males. Specifically, H2A.Z.1KA preferentially impacts genes involved in synaptic function, suggesting that acetyl-defective H2A.Z.1 impairs memory by altering synaptic regulation. Finally, we describe, for the first time, that H2A.Z is also involved in alternative splicing of neuronal genes, whereby H2A.Z depletion, as well as expression of H2A.Z.1 lysine mutants influence transcription and splicing of different gene targets, suggesting that H2A.Z.1 can impact behavior through effects on both splicing and gene expression. This is the first study to demonstrate that direct manipulation of H2A.Z post-translational modifications regulates memory, whereby acetylation adds another regulatory layer by which histone variants can fine tune higher brain functions through effects on gene expression and splicing.
PMID:38366138 | DOI:10.1038/s41386-024-01817-2
Nitrogen sensing and regulatory networks: It's about time and space
Plant Cell. 2024 Feb 14:koae038. doi: 10.1093/plcell/koae038. Online ahead of print.
ABSTRACT
A plant's response to external and internal nitrogen signals/status relies on sensing and signaling mechanisms that operate across spatial and temporal dimensions. From a comprehensive systems biology perspective, this involves integrating nitrogen responses in different cell types and over long distances to ensure organ coordination in real time and yield practical applications. In this prospective review, we focus on novel aspects of nitrogen (N) sensing/signaling uncovered using temporal and spatial systems biology approaches, largely in the model Arabidopsis. The temporal aspects span: transcriptional responses to N-dose mediated by Michaelis-Menten kinetics; the role of the master NLP7 transcription factor as a nitrate sensor, its nitrate-dependent TF nuclear retention, its "hit-and-run" mode of target gene regulation and temporal transcriptional cascade identified by "Network Walking". Spatial aspects of N-sensing/signaling have been uncovered in cell type-specific studies in roots and in root-to-shoot communication. We explore new approaches using single cell sequencing data, trajectory inference and pseudotime analysis as well as machine learning and artificial intelligence approaches. Finally, unveiling the mechanisms underlying the spatial dynamics of nitrogen sensing/signaling networks across species from model-to-crop could pave the way for translational studies to improve nitrogen-use efficiency in crops. Such outcomes could potentially reduce the detrimental effects of excessive fertilizer usage on groundwater pollution and greenhouse gas emissions.
PMID:38366121 | DOI:10.1093/plcell/koae038
Dissecting the spatiotemporal diversity of adult neural stem cells
Mol Syst Biol. 2024 Feb 16. doi: 10.1038/s44320-024-00022-z. Online ahead of print.
ABSTRACT
Adult stem cells are important for tissue turnover and regeneration. However, in most adult systems it remains elusive how stem cells assume different functional states and support spatially patterned tissue architecture. Here, we dissected the diversity of neural stem cells in the adult zebrafish brain, an organ that is characterized by pronounced zonation and high regenerative capacity. We combined single-cell transcriptomics of dissected brain regions with massively parallel lineage tracing and in vivo RNA metabolic labeling to analyze the regulation of neural stem cells in space and time. We detected a large diversity of neural stem cells, with some subtypes being restricted to a single brain region, while others were found globally across the brain. Global stem cell states are linked to neurogenic differentiation, with different states being involved in proliferative and non-proliferative differentiation. Our work reveals principles of adult stem cell organization and establishes a resource for the functional manipulation of neural stem cell subtypes.
PMID:38365956 | DOI:10.1038/s44320-024-00022-z
Forum on immune digital twins: a meeting report
NPJ Syst Biol Appl. 2024 Feb 16;10(1):19. doi: 10.1038/s41540-024-00345-5.
ABSTRACT
Medical digital twins are computational models of human biology relevant to a given medical condition, which are tailored to an individual patient, thereby predicting the course of disease and individualized treatments, an important goal of personalized medicine. The immune system, which has a central role in many diseases, is highly heterogeneous between individuals, and thus poses a major challenge for this technology. In February 2023, an international group of experts convened for two days to discuss these challenges related to immune digital twins. The group consisted of clinicians, immunologists, biologists, and mathematical modelers, representative of the interdisciplinary nature of medical digital twin development. A video recording of the entire event is available. This paper presents a synopsis of the discussions, brief descriptions of ongoing digital twin projects at different stages of progress. It also proposes a 5-year action plan for further developing this technology. The main recommendations are to identify and pursue a small number of promising use cases, to develop stimulation-specific assays of immune function in a clinical setting, and to develop a database of existing computational immune models, as well as advanced modeling technology and infrastructure.
PMID:38365857 | DOI:10.1038/s41540-024-00345-5
Role of Hemigraphis alternata in wound healing: metabolomic profiling and molecular insights into mechanisms
Sci Rep. 2024 Feb 16;14(1):3872. doi: 10.1038/s41598-024-54352-x.
ABSTRACT
Hemigraphis alternata (H. alternata), commonly known as Red Flame Ivy, is widely recognized for its wound healing capabilities. However, the pharmacologically active plant components and their mechanisms of action in wound healing are yet to be determined. This study presents the mass spectrometry-based global metabolite profiling of aqueous and ethanolic extract of H. alternata leaves. The analysis identified 2285 metabolites from 24,203 spectra obtained in both positive and negative polarities. The identified metabolites were classified under ketones, carboxylic acids, primary aliphatic amines, steroids and steroid derivatives. We performed network pharmacology analysis to explore metabolite-protein interactions and identified 124 human proteins as targets for H. alternata metabolites. Among these, several of them were implicated in wound healing including prothrombin (F2), alpha-2A adrenergic receptor (ADRA2A) and fibroblast growth factor receptor 1 (FGFR1). Gene ontology analysis of target proteins enriched cellular functions related to glucose metabolic process, platelet activation, membrane organization and response to wounding. Additionally, pathway enrichment analysis revealed potential molecular network involved in wound healing. Moreover, in-silico docking analysis showed strong binding energy between H. alternata metabolites with identified protein targets (F2 and PTPN11). Furthermore, the key metabolites involved in wound healing were further validated by multiple reaction monitoring-based targeted analysis.
PMID:38365839 | DOI:10.1038/s41598-024-54352-x
A genome and gene catalog of the aquatic microbiomes of the Tibetan Plateau
Nat Commun. 2024 Feb 16;15(1):1438. doi: 10.1038/s41467-024-45895-8.
ABSTRACT
The Tibetan Plateau supplies water to nearly 2 billion people in Asia, but climate change poses threats to its aquatic microbial resources. Here, we construct the Tibetan Plateau Microbial Catalog by sequencing 498 metagenomes from six water ecosystems (saline lakes, freshwater lakes, rivers, hot springs, wetlands and glaciers). Our catalog expands knowledge of regional genomic diversity by presenting 32,355 metagenome-assembled genomes that de-replicated into 10,723 representative genome-based species, of which 88% were unannotated. The catalog contains nearly 300 million non-redundant gene clusters, of which 15% novel, and 73,864 biosynthetic gene clusters, of which 50% novel, thus expanding known functional diversity. Using these data, we investigate the Tibetan Plateau aquatic microbiome's biogeography along a distance of 2,500 km and >5 km in altitude. Microbial compositional similarity and the shared gene count with the Tibetan Plateau microbiome decline along with distance and altitude difference, suggesting a dispersal pattern. The Tibetan Plateau Microbial Catalog stands as a substantial repository for high-altitude aquatic microbiome resources, providing potential for discovering novel lineages and functions, and bridging knowledge gaps in microbiome biogeography.
PMID:38365793 | DOI:10.1038/s41467-024-45895-8
High compositional and functional similarity in the microbiome of deep-sea sponges
ISME J. 2024 Jan 8;18(1):wrad030. doi: 10.1093/ismejo/wrad030.
ABSTRACT
Sponges largely depend on their symbiotic microbes for their nutrition, health, and survival. This is especially true in high microbial abundance (HMA) sponges, where filtration is usually deprecated in favor of a larger association with prokaryotic symbionts. Sponge-microbiome association is substantially less understood for deep-sea sponges than for shallow water species. This is most unfortunate, since HMA sponges can form massive sponge grounds in the deep sea, where they dominate the ecosystems, driving their biogeochemical cycles. Here, we assess the microbial transcriptional profile of three different deep-sea HMA sponges in four locations of the Cantabrian Sea and compared them to shallow water HMA and LMA (low microbial abundance) sponge species. Our results reveal that the sponge microbiome has converged in a fundamental metabolic role for deep-sea sponges, independent of taxonomic relationships or geographic location, which is shared in broad terms with shallow HMA species. We also observed a large number of redundant microbial members performing the same functions, likely providing stability to the sponge inner ecosystem. A comparison between the community composition of our deep-sea sponges and another 39 species of HMA sponges from deep-sea and shallow habitats, belonging to the same taxonomic orders, suggested strong homogeneity in microbial composition (i.e. weak species-specificity) in deep sea species, which contrasts with that observed in shallow water counterparts. This convergence in microbiome composition and functionality underscores the adaptation to an extremely restrictive environment with the aim of exploiting the available resources.
PMID:38365260 | DOI:10.1093/ismejo/wrad030
Immune Response following FLASH and Conventional Radiation in Diffuse Midline Glioma (DMG)
Int J Radiat Oncol Biol Phys. 2024 Feb 14:S0360-3016(24)00300-6. doi: 10.1016/j.ijrobp.2024.01.219. Online ahead of print.
ABSTRACT
PURPOSE: Diffuse Midline Glioma (DMG) is a fatal tumor traditionally treated with radiotherapy (RT) and previously characterized as having a non-inflammatory tumor immune microenvironment (TIME). FLASH is a novel RT technique using ultra-high dose rate, which is associated with decreased toxicity and effective tumor control. However, the effect of FLASH and conventional (CONV) RT on the DMG TIME have not yet been explored.
METHODS: Here, we perform single-cell RNA sequencing and flow cytometry on immune cells isolated from an orthotopic syngeneic murine model of brainstem DMG following the use of FLASH (90Gy/sec) or CONV (2Gy/min) dose-rate RT, and compare to unirradiated tumor (SHAM).
RESULTS: At day 4 post-RT, FLASH exerts similar effects as CONV in the predominant microglial (MG) population, including the presence of two activated subtypes. However, at day 10 post-RT, we observe a significant increase in type 1 interferon alpha receptor (IFNAR+) in MG in CONV and SHAM compared to FLASH. In the non-resident myeloid clusters of macrophages (MACs) and dendritic cells (DCs), we find increased type 1 interferon (IFN1) pathway enrichment for CONV compared to FLASH and SHAM by scRNA-seq. We observe this trend by flow cytometry at day 4 post-RT in IFNAR+ MACs and DCs, which equalizes by day 10 post-RT. DMG control and murine survival are equivalent between RT dose rates.
CONCLUSION: Our work is the first to map CONV and FLASH immune alterations of the DMG TIME with single-cell resolution. While DMG tumor control and survival are similar between CONV and FLASH, we find that changes in immune compartments differ over time. Importantly, while both RT modalities increase IFN1, we find that the timing of this response is cell-type and dose-rate dependent. These temporal differences, particularly in the context of tumor control, warrant further study.
PMID:38364947 | DOI:10.1016/j.ijrobp.2024.01.219
Prediction of protein-RNA interactions from single-cell transcriptomic data
Nucleic Acids Res. 2024 Feb 14:gkae076. doi: 10.1093/nar/gkae076. Online ahead of print.
ABSTRACT
Proteins are crucial in regulating every aspect of RNA life, yet understanding their interactions with coding and noncoding RNAs remains limited. Experimental studies are typically restricted to a small number of cell lines and a limited set of RNA-binding proteins (RBPs). Although computational methods based on physico-chemical principles can predict protein-RNA interactions accurately, they often lack the ability to consider cell-type-specific gene expression and the broader context of gene regulatory networks (GRNs). Here, we assess the performance of several GRN inference algorithms in predicting protein-RNA interactions from single-cell transcriptomic data, and propose a pipeline, called scRAPID (single-cell transcriptomic-based RnA Protein Interaction Detection), that integrates these methods with the catRAPID algorithm, which can identify direct physical interactions between RBPs and RNA molecules. Our approach demonstrates that RBP-RNA interactions can be predicted from single-cell transcriptomic data, with performances comparable or superior to those achieved for the well-established task of inferring transcription factor-target interactions. The incorporation of catRAPID significantly enhances the accuracy of identifying interactions, particularly with long noncoding RNAs, and enables the identification of hub RBPs and RNAs. Additionally, we show that interactions between RBPs can be detected based on their inferred RNA targets. The software is freely available at https://github.com/tartaglialabIIT/scRAPID.
PMID:38364867 | DOI:10.1093/nar/gkae076
The chromatin accessibility dynamics during cell fate specifications in zebrafish early embryogenesis
Nucleic Acids Res. 2024 Feb 14:gkae095. doi: 10.1093/nar/gkae095. Online ahead of print.
ABSTRACT
Chromatin accessibility plays a critical role in the regulation of cell fate decisions. Although gene expression changes have been extensively profiled at the single-cell level during early embryogenesis, the dynamics of chromatin accessibility at cis-regulatory elements remain poorly studied. Here, we used a plate-based single-cell ATAC-seq method to profile the chromatin accessibility dynamics of over 10 000 nuclei from zebrafish embryos. We investigated several important time points immediately after zygotic genome activation (ZGA), covering key developmental stages up to dome. The results revealed key chromatin signatures in the first cell fate specifications when cells start to differentiate into enveloping layer (EVL) and yolk syncytial layer (YSL) cells. Finally, we uncovered many potential cell-type specific enhancers and transcription factor motifs that are important for the cell fate specifications.
PMID:38364856 | DOI:10.1093/nar/gkae095
Endosperm cell death: roles and regulation in angiosperms
J Exp Bot. 2024 Feb 14:erae052. doi: 10.1093/jxb/erae052. Online ahead of print.
ABSTRACT
Double fertilization in angiosperms results in the formation of a second zygote, the fertilized endosperm. Unlike its embryo sibling, the endosperm is a transient structure that eventually undergoes developmentally controlled programmed cell death (PCD) at specific time points of seed development or germination. The nature of endosperm PCD exhibits a considerable diversity, both across different angiosperm taxa and within distinct endosperm tissues. In endosperm-less species, PCD might cause central cell degeneration as a mechanism preventing the formation of a fertilized endosperm. In most other angiosperms, embryo growth necessitates the elimination of surrounding endosperm cells. Nevertheless, complete elimination of the endosperm is rare, and in most cases, specific endosperm tissues persist. In mature seeds, these persisting cells may be dead, such as the starchy endosperm in cereals, or remain alive to die only during germination, like the cereal aleurone or the endosperm of castor beans. In this review, we explore the current knowledge surrounding the cellular, molecular, and genetic aspects of endosperm PCD, and the influence environmental stresses have on PCD processes. Overall, this review provides an exhaustive overview of endosperm PCD processes in angiosperms, shedding light on its diverse mechanisms and its significance in seed development and seedling establishment.
PMID:38364847 | DOI:10.1093/jxb/erae052
Chromatograms and Mass Spectra of High-Mannose and Paucimannose <em>N</em>-Glycans for Rapid Isomeric Identifications
J Proteome Res. 2024 Feb 16. doi: 10.1021/acs.jproteome.3c00640. Online ahead of print.
ABSTRACT
N-Linked glycosylation is one of the most essential post-translational modifications of proteins. However, N-glycan structural determination remains challenging because of the small differences in structures between isomers. In this study, we constructed a database containing collision-induced dissociation MSn mass spectra and chromatograms of high-performance liquid chromatography for the rapid identification of high-mannose and paucimannose N-glycan isomers. These N-glycans include isomers by breaking of arbitrary numbers of glycosidic bonds at arbitrary positions of canonical Man9GlcNAc2 N-glycans. In addition, some GlcMannGlcNAc2 N-glycan isomers were included in the database. This database is particularly useful for the identification of the N-glycans not in conventional N-glycan standards. This study demonstrated the application of the database to structural assignment for high-mannose N-glycans extracted from bovine whey proteins, soybean proteins, human mammary epithelial cells, and human breast carcinoma cells. We found many N-glycans that are not expected to be generated by conventional biosynthetic pathways of multicellular eukaryotes.
PMID:38364797 | DOI:10.1021/acs.jproteome.3c00640
<em>Staphylococcus aureus</em> AbcA transporter enhances persister formation under β-lactam exposure
Antimicrob Agents Chemother. 2024 Feb 16:e0134023. doi: 10.1128/aac.01340-23. Online ahead of print.
ABSTRACT
We evaluated the role of Staphylococcus aureus AbcA transporter in bacterial persistence and survival following exposure to the bactericidal agents nafcillin and oxacillin at both the population and single-cell levels. We show that AbcA overexpression resulted in resistance to nafcillin but not oxacillin. Using distinct fluorescent reporters of cell viability and AbcA expression, we found that over 6-14 hours of persistence formation, the proportion of AbcA reporter-expressing cells assessed by confocal microscopy increased sixfold as cell viability reporters decreased. Similarly, single-cell analysis in a high-throughput microfluidic system found a strong correspondence between antibiotic exposure and AbcA reporter expression. Persister cells grown in the absence of antibiotics showed neither an increase in nafcillin MIC nor in abcA transcript levels, indicating that survival was not associated with stable mutational resistance or abcA overexpression. Furthermore, persister cell levels on exposure to 1×MIC and 25×MIC of nafcillin decreased in an abcA knockout mutant. Survivors of nafcillin and oxacillin treatment overexpressed transporter AbcA, contributing to an enrichment of the number of persisters during treatment with pump-substrate nafcillin but not with pump-non-substrate oxacillin, indicating that efflux pump expression can contribute selectively to the survival of a persister population.
PMID:38364015 | DOI:10.1128/aac.01340-23
Cetylpyridinium chloride and chlorhexidine show antiviral activity against Influenza A virus and Respiratory Syncytial virus in vitro
PLoS One. 2024 Feb 16;19(2):e0297291. doi: 10.1371/journal.pone.0297291. eCollection 2024.
ABSTRACT
BACKGROUND: The oral cavity is the site of entry and replication for many respiratory viruses. Furthermore, it is the source of droplets and aerosols that facilitate viral transmission. It is thought that appropriate oral hygiene that alters viral infectivity might reduce the spread of respiratory viruses and contribute to infection control.
MATERIALS AND METHODS: Here, we analyzed the antiviral activity of cetylpyridinium chloride (CPC), chlorhexidine (CHX), and three commercial CPC and CHX-containing mouthwash preparations against the Influenza A virus and the Respiratory syncytial virus. To do so the aforementioned compounds and preparations were incubated with the Influenza A virus or with the Respiratory syncytial virus. Next, we analyzed the viability of the treated viral particles.
RESULTS: Our results indicate that CPC and CHX decrease the infectivity of both the Influenza A virus and the Respiratory Syncytial virus in vitro between 90 and 99.9% depending on the concentration. Likewise, CPC and CHX-containing mouthwash preparations were up to 99.99% effective in decreasing the viral viability of both the Influenza A virus and the Respiratory syncytial virus in vitro.
CONCLUSION: The use of a mouthwash containing CPC or CHX alone or in combination might represent a cost-effective measure to limit infection and spread of enveloped respiratory viruses infecting the oral cavity, aiding in reducing viral transmission. Our findings may stimulate future clinical studies to evaluate the effects of CPC and CHX in reducing viral respiratory transmissions.
PMID:38363760 | DOI:10.1371/journal.pone.0297291
Repurposing the mammalian RNA-binding protein Musashi-1 as an allosteric translation repressor in bacteria
Elife. 2024 Feb 16;12:RP91777. doi: 10.7554/eLife.91777.
ABSTRACT
The RNA recognition motif (RRM) is the most common RNA-binding protein domain identified in nature. However, RRM-containing proteins are only prevalent in eukaryotic phyla, in which they play central regulatory roles. Here, we engineered an orthogonal post-transcriptional control system of gene expression in the bacterium Escherichia coli with the mammalian RNA-binding protein Musashi-1, which is a stem cell marker with neurodevelopmental role that contains two canonical RRMs. In the circuit, Musashi-1 is regulated transcriptionally and works as an allosteric translation repressor thanks to a specific interaction with the N-terminal coding region of a messenger RNA and its structural plasticity to respond to fatty acids. We fully characterized the genetic system at the population and single-cell levels showing a significant fold change in reporter expression, and the underlying molecular mechanism by assessing the in vitro binding kinetics and in vivo functionality of a series of RNA mutants. The dynamic response of the system was well recapitulated by a bottom-up mathematical model. Moreover, we applied the post-transcriptional mechanism engineered with Musashi-1 to specifically regulate a gene within an operon, implement combinatorial regulation, and reduce protein expression noise. This work illustrates how RRM-based regulation can be adapted to simple organisms, thereby adding a new regulatory layer in prokaryotes for translation control.
PMID:38363283 | DOI:10.7554/eLife.91777
Fusion-fission-mitophagy cycling and metabolic reprogramming coordinate nerve growth factor (NGF)-dependent neuronal differentiation
FEBS J. 2024 Feb 16. doi: 10.1111/febs.17083. Online ahead of print.
ABSTRACT
Neuronal differentiation is regulated by nerve growth factor (NGF) and other neurotrophins. We explored the impact of NGF on mitochondrial dynamics and metabolism through time-lapse imaging, metabolomics profiling, and computer modeling studies. We show that NGF may direct differentiation by stimulating fission, thereby causing selective mitochondrial network fragmentation and mitophagy, ultimately leading to increased mitochondrial quality and respiration. Then, we reconstructed the dynamic fusion-fission-mitophagy cycling of mitochondria in a computer model, integrating these processes into a single network mechanism. Both the computational model and the simulations are able to reproduce the proposed mechanism in terms of mitochondrial dynamics, levels of reactive oxygen species (ROS), mitophagy, and mitochondrial quality, thus providing a computational tool for the interpretation of the experimental data and for future studies aiming to detail further the action of NGF on mitochondrial processes. We also show that changes in these mitochondrial processes are intertwined with a metabolic function of NGF in differentiation: NGF directs a profound metabolic rearrangement involving glycolysis, TCA cycle, and the pentose phosphate pathway, altering the redox balance. This metabolic rewiring may ensure: (a) supply of both energy and building blocks for the anabolic processes needed for morphological reorganization, as well as (b) redox homeostasis.
PMID:38362803 | DOI:10.1111/febs.17083
Challenging old microbiological treasures for natural compound biosynthesis capacity
Front Bioeng Biotechnol. 2024 Feb 1;12:1255151. doi: 10.3389/fbioe.2024.1255151. eCollection 2024.
ABSTRACT
Strain collections are a treasure chest of numerous valuable and taxonomically validated bioresources. The Leibniz Institute DSMZ is one of the largest and most diverse microbial strain collections worldwide, with a long tradition of actinomycetes research. Actinomycetes, especially the genus Streptomyces, are renowned as prolific producers of antibiotics and many other bioactive natural products. In light of this, five Streptomyces strains, DSM 40971T, DSM 40484T, DSM 40713T, DSM 40976T, and DSM 40907T, which had been deposited a long time ago without comprehensive characterization, were the subject of polyphasic taxonomic studies and genome mining for natural compounds based on in vitro and in silico analyses. Phenotypic, genetic, and phylogenomic studies distinguished the strains from their closely related neighbors. The digital DNA-DNA hybridization and average nucleotide identity values between the five strains and their close, validly named species were below the threshold of 70% and 95%-96%, respectively, determined for prokaryotic species demarcation. Therefore, the five strains merit being considered as novel Streptomyces species, for which the names Streptomyces kutzneri sp. nov., Streptomyces stackebrandtii sp. nov., Streptomyces zähneri sp. nov., Streptomyces winkii sp. nov., and Streptomyces kroppenstedtii sp. nov. are proposed. Bioinformatics analysis of the genome sequences of the five strains revealed their genetic potential for the production of secondary metabolites, which helped identify the natural compounds cinerubin B from strain DSM 40484T and the phosphonate antibiotic phosphonoalamide from strain DSM 40907T and highlighted strain DSM 40976T as a candidate for regulator-guided gene cluster activation due to the abundance of numerous "Streptomyces antibiotic regulatory protein" (SARP) genes.
PMID:38361790 | PMC:PMC10867783 | DOI:10.3389/fbioe.2024.1255151
Machine learning for functional protein design
Nat Biotechnol. 2024 Feb;42(2):216-228. doi: 10.1038/s41587-024-02127-0. Epub 2024 Feb 15.
ABSTRACT
Recent breakthroughs in AI coupled with the rapid accumulation of protein sequence and structure data have radically transformed computational protein design. New methods promise to escape the constraints of natural and laboratory evolution, accelerating the generation of proteins for applications in biotechnology and medicine. To make sense of the exploding diversity of machine learning approaches, we introduce a unifying framework that classifies models on the basis of their use of three core data modalities: sequences, structures and functional labels. We discuss the new capabilities and outstanding challenges for the practical design of enzymes, antibodies, vaccines, nanomachines and more. We then highlight trends shaping the future of this field, from large-scale assays to more robust benchmarks, multimodal foundation models, enhanced sampling strategies and laboratory automation.
PMID:38361074 | DOI:10.1038/s41587-024-02127-0
SPARKing academic technologies across the valley of death
Nat Biotechnol. 2024 Feb;42(2):339-342. doi: 10.1038/s41587-024-02130-5.
NO ABSTRACT
PMID:38361072 | DOI:10.1038/s41587-024-02130-5
Structural insights into the ubiquitylation strategy of the oligomeric CRL2<sup>FEM1B</sup> E3 ubiquitin ligase
EMBO J. 2024 Feb 15. doi: 10.1038/s44318-024-00047-y. Online ahead of print.
ABSTRACT
Cullin-RING E3 ubiquitin ligase (CRL) family members play critical roles in numerous biological processes and diseases including cancer and Alzheimer's disease. Oligomerization of CRLs has been reported to be crucial for the regulation of their activities. However, the structural basis for its regulation and mechanism of its oligomerization are not fully known. Here, we present cryo-EM structures of oligomeric CRL2FEM1B in its unneddylated state, neddylated state in complex with BEX2 as well as neddylated state in complex with FNIP1/FLCN. These structures reveal that asymmetric dimerization of N8-CRL2FEM1B is critical for the ubiquitylation of BEX2 while FNIP1/FLCN is ubiquitylated by monomeric CRL2FEM1B. Our data present an example of the asymmetric homo-dimerization of CRL. Taken together, this study sheds light on the ubiquitylation strategy of oligomeric CRL2FEM1B according to substrates with different scales.
PMID:38360992 | DOI:10.1038/s44318-024-00047-y