Biology subjects

Zhang, F.

Publications and source records attributed to Zhang, F..

At least 235 records · Page 13Linked to original sources

bioRxiv2023

Harmonized diffusion MRI data and white matter measures from the baseline Adolescent Brain Cognitive Development (ABCD) study

The Adolescent Brain Cognitive Development (ABCD) study has collected data from over 10,000 children across 21 sites, providing valuable insights into adolescent brain development. However, site-specific scanner variability has made it challenging to use diffusion MRI (dMRI) data from this study. To address this, a database of harmonized and processed ABCD dMRI data has been created, comprising quality-controlled imaging data from 9345 subjects. This resource required significant computational effort, taking [~]50,000 CPU hours to harmonize the data, perform white matter parcellation, and run whole brain tractography. The database includes harmonized dMRI data, 800 white matter clusters, 73 anatomically labeled white matter tracts both in full-resolution (for analysis) and low-resolution (for visualization), and 804 different dMRI-derived measures per subject. It is available via the NIMH Data Archive and offers tremendous potential for scientific discoveries in structural connectivity studies of neurodevelopment in children and adolescents. Additionally, several post-harmonization experiments were conducted to demonstrate the success of the harmonization process on the ABCD dataset.

neuroscience↗

bioRxiv2023

Duckweed evolution: from land back to water

Terrestialization is supposedly an important evolutionary process plant experience. However, directions of land back to water acquired little attention. Here we integrate multiproxy evidence to elucidate the evolution of duckweed. Three genera of duckweed show chronologically gradient degeneration in roots structure and stomatal function and decrease in lignocellulose content, accompanied by gradual contraction in relevant gene numbers and/or decline in transcription. The gene numbers in the main phytohormonal pathway are also gradually decreased. The co-action of auxin and rhizoid development gene causes a gradual decrease in adventitious roots. The significant expansion of the flavonoid pathway is also related to the adaptation of duckweed to floating growth. This study reconstructs the evolution history of duckweeds from land back to water, reverse to that of early land plants. SummaryWith terrestrialization being the popularly acknowledged plant evolutionary process, little is known about the evolution of higher plant from land back to water. Here we integrate multiproxy evidence to elucidate the gradual reverse evolution of duckweed. Three genera of duckweed show chronologically gradient degeneration in the structure of roots, the function of stomata, and decrease in lignocellulose content, accompanied by gradient contraction in relevant gene numbers and/or decline in transcript expression. The gene numbers in the main phytohormonal pathway are also gradually decreased. The co-action of auxin and rhizoid development gene causes a gradual decrease in adventitious roots. The significant expansion of the flavonoid pathway is also highly related to the adaptation of duckweed to floating growth. Our study combined with the fossil evidence reconstruct the evolution history of duckweeds from land back to water, reverse to that of early land plants. This study reconstructed the process of how a land plant returns to water, a reverse evolutionary approach which is different from what we studied in textbook about plant terrestrialization. This finding could be helpful for us to deeply and widely understand the adaptation of plant to the environment, and to expand and deepen the knowledge of evolution theory.

evolutionary biology↗

bioRxiv2023

Artificially cultivated duckweed: a high-efficiency starch producer

The increasing demand for starch has been a social struggle. We report a new technology that efficiently produces starch from duckweed. Although Landoltia punctata has a dramatic contraction of gene families, its starch content and productivity reached 72.2% (dry basis) and 10.4 g m-2 d-1 in 10 days, equivalent to a yield of 38.0 t ha-1 y-1 under nutrient limitation and CO2 elevation treatment. Meanwhile, we also examined the mechanism of duckweeds high starch accumulation. This is exhibited in the regulation of DNA methylation and transcription factors as well as the significantly up-regulated transcription levels and the increased enzyme activities of key genes in starch biosynthesis. Meantime, while nitrogen redistribution was enhanced, sucrose biosynthesis and transportation, and lignocellulose biosynthesis were all reduced. These alterations led to a reduction in lignocellulose and protein content and ultimately an increase in an accumulation of starch in the chloroplast. This work demonstrates duckweeds potential of being a highly efficient starch producer.

plant biology↗

bioRxiv2023

PGAR-Zernike: an ultra-fast, accurate and fully open-sourcestructure retrieval toolkit for convenient structural database construction

With the release of AlphaFold2, protein model databases are growing at an unprecedented rate. Efficient structure retrieval schemes are becoming more and more important to quickly analyze structure models. The core problem in structural retrieval is how to measure the similarity between structures. Some structure alignment algorithms can solve this problem but at a substantial time cost. At present, the state-of-the-art method is to convert protein structures into 3D Zernike descriptors and evaluate the similarity between structures by Euclidean distance. However, methods for computing 3D Zernike descriptors of protein structures are almost always based on structural surfaces and most are web servers, which is not conducive for users to analyze customized datasets. To overcome this limitation, we propose PGAR-Zernike, a convenient toolkit for computing different types of Zernike descriptors of structures: the user simply needs to enter one line of command to calculate the Zernike descriptors of all structures in a customized datasets. Compared with the state-of-the-art method based on 3D Zernike descriptors and an efficient structural comparison tool, PGAR-Zernike achieves higher retrieval accuracy and binary classification accuracy on benchmark datasets with different attributes. In addition, we show how PGA-Zernike completes the construction of the descriptor database and the protocol used for the PDB dataset so as to facilitate the local deployment of this tool for interested readers. We construct a demonstration containing 590685 structures; at this scale, our retrieval system takes only 4 ~ 9 seconds to complete a retrieval, and experiments show that it reaches the state-of-the-art level in terms of accuracy. PGAR-Zernike is an open-source toolkit, whose source code and related data are accessible at https://github.com/junhaiqi/PGAR-Zernike/.

bioinformatics↗

bioRxiv2023

Clonal associations of lymphocyte subsets and functional states revealed by single cell antigen receptor profiling of T and B cells in rheumatoid arthritis synovium

Rheumatoid arthritis (RA) is an autoimmune disease initiated by antigen-specific T cells and B cells, which promote synovial inflammation through a complex set of interactions with innate immune and stromal cells. To better understand the phenotypes and clonal relationships of synovial T and B cells, we performed single-cell RNA and repertoire sequencing on paired synovial tissue and peripheral blood samples from 12 donors with seropositive RA ranging from early to chronic disease. Paired transcriptomic-repertoire analyses highlighted 3 clonally distinct CD4 T cells populations that were enriched in RA synovium: T peripheral helper (Tph) and T follicular helper (Tfh) cells, CCL5+ T cells, and T regulatory cells (Tregs). Among these cells, Tph cells showed a unique transcriptomic signature of recent T cell receptor (TCR) activation, and clonally expanded Tph cells expressed an elevated transcriptomic effector signature compared to non-expanded Tph cells. CD8 T cells showed higher oligoclonality than CD4 T cells, and the largest CD8 T cell clones in synovium were highly enriched in GZMK+ cells. TCR analyses revealed CD8 T cells with likely viral-reactive TCRs distributed across transcriptomic clusters and definitively identified MAIT cells in synovium, which showed transcriptomic features of TCR activation. Among B cells, non-naive B cells including age-associated B cells (ABC), NR4A1+ activated B cells, and plasma cells, were enriched in synovium and had higher somatic hypermutation rates compared to blood B cells. Synovial B cells demonstrated substantial clonal expansion, with ABC, memory, and activated B cells clonally linked to synovial plasma cells. Together, these results reveal clonal relationships between functionally distinct lymphocyte populations that infiltrate RA synovium.

immunology↗

bioRxiv2023

Taxonomic distribution of metabolic functions underpin nutrient cycling in Trichodesmium consortia

The photosynthetic and diazotrophic cyanobacterium Trichodesmium is a key contributor to marine biogeochemical cycles in the subtropical-oligotrophic oceans. Trichodesmium forms colonies that harbor a distinct microbial community, which expands their functional potential and is predicted to influence the cycling of carbon, nitrogen, phosphorus and iron (C, N, P, and Fe). To link key traits to taxa and elucidate how community structure influences nutrient cycling, we assessed Red Sea Trichodesmium colonies using metagenomics and metaproteomics. This diverse consortium comprises bacteria that typically associate with algae and particles, such as the ubiquitous Alteromonas macleodii, but also lineages specific to Trichodesmium, such as members from the order Balneolales. These bacteria carry functional traits that would influence resource cycling in the consortium, including siderophore biosynthesis, reduced phosphorus metabolism, vitamins, denitrification, and dissimilatory-nitrate-reduction-to-ammonium (DNRA) pathways. Denitrification and DNRA appeared to be modular as bacteria collectively completed the steps for these pathways. The vast majority of associated bacteria were auxotrophic for vitamins, indicating the interdependency of consortium members. Trichodesmium in turn may rely on associated bacteria to meet its high Fe demand as several lineages can synthesize the photolabile siderophores vibrioferrin, rhizoferrin, and petrobactin, enhancing the bioavailability of particulate-Fe to the entire consortium. Our results highlight that Trichodesmium is a hotspot for C, N, P, Fe, and vitamin exchange. The functional redundancy of nutrient cycling in the consortium likely underpins its resilience within an ever-changing global environment. ImportanceColonies of the cyanobacteria Trichodesmium act as a biological hotspot for the usage and recycling of key resources such as C, N, P and Fe within an otherwise oligotrophic environment. While Trichodesmium colonies are known to interact with a unique community of algae and particle-associated microbes, our understanding of the taxa that populate these colonies and the gene functions they encode is still limited. Characterizing the taxa and adaptive strategies that influence consortium physiology and its concomitant biogeochemistry is critical in a future ocean predicted to have increasing particulate fluxes and resource-depleted regions.

microbiology↗

bioRxiv2023

Rational design of immune gene therapy combinations via in vivo CRISPR activation screen of tumor microenvironment modulators

The hostile tumor microenvironment (TME) is major challenge for cancer immunotherapies. Here, we design and perform TME-targeted in vivo CRISPR activation (CRISPRa) screens to uncover factors that promote anti-tumor immunity, culminating in rationally designed immune gene therapy combinations. Through adeno-associated virus (AAV) delivery, multiplexed activation of pooled immunoregulatory genes encoding antigen presentation, cytokine, and co-stimulation molecules (APCM) leads to enhanced anti-tumor immunity. APCM screen in metastatic tumors identifies Cd80, Tnfsf14, Cxcl10, Tnfsf18, Tnfsf9, and Ifng as the top immunostimulatory candidates. AAV-mediated delivery of these factors individually or in combination shows anti-tumor efficacy across different cancer models. Further optimization pinpoints Ifng+Tnfsf9+Il12b(Il12/Il23) as a potent therapeutic combination, leading to increased IFN-{gamma}+CD8+ and tissue-resident memory T cells. APCM therapy synergizes with CAR-T cell therapy against human solid tumors in vivo. APCM-based CRISPRa screen and gene activation systems can thus be leveraged for the rapid generation of off-the-shelf immune gene therapies against solid tumors.

immunology↗

bioRxiv2023

Multiplexed repression of immunosuppressive genes as combinatorial cancer immunotherapy

Checkpoint blockade immunotherapy is a potent class of cancer treatment, however, the complex immunosuppressive tumor microenvironment (TME) often requires multi-agent combinations to be effective. Current cancer immunotherapy combination approaches are cumbersome, usually involving one-drug-at-a-time scheme. Here, we devise Multiplex Universal Combinatorial Immunotherapy via Gene-silencing (MUCIG), as a versatile approach for combinatorial cancer immunotherapy. We harness CRISPR-Cas13d to efficiently target multiple endogenous immunosuppressive genes on demand, allowing us to silence various combinations of multiple immunosuppressive factors in the TME. Intratumoral AAV-mediated administration of MUCIG (AAV-MUCIG) elicits significant anti-tumor activity with several Cas13d gRNA compositions. TME target expression analysis driven optimization led to a simplified off-the-shelf MUCIG targeting a four gene combination (PGGC: Pdl1, Galectin9, Galectin3 and Cd47). AAV-PGGC shows significant in vivo efficacy in syngeneic tumor models. Single cell and flow profiling revealed that AAV-PGGC remodeled the TME by increasing CD8+ T cell infiltration and reducing myeloid-derived immunosuppressive cells (MDSCs). MUCIG thus serves as a universal method to silence multiple immune genes in vivo, and can be delivered via AAV as a therapeutic approach.

immunology↗

bioRxiv2023

Structural insights into TRPV4-Rho GTPase signaling complex function and disease

Crosstalk between ion channels and small GTPases is critical during homeostasis and disease1, but little is known about the structural underpinnings of these interactions. TRPV4 is a polymodal, calcium-permeable cation channel that has emerged as a potential therapeutic target in multiple conditions2-5. Gain-of-function mutations also cause hereditary neuromuscular disease6-11. Here, we present cryo-EM structures of human TRPV4 in complex with RhoA in the apo, antagonist-bound closed, and agonist-bound open states. These structures reveal the mechanism of ligand-dependent TRPV4 gating. Channel activation is associated with rigid-body rotation of the intracellular ankyrin repeat domain, but state-dependent interaction with membrane-anchored RhoA constrains this movement. Notably, many residues at the TRPV4-RhoA interface are mutated in disease and perturbing this interface by introducing mutations into either TRPV4 or RhoA increases TRPV4 channel activity. Together, these results suggest that the interaction strength between TRPV4 and RhoA tunes TRPV4-mediated calcium homeostasis and actin remodeling, and that disruption of TRPV4-RhoA interactions leads to TRPV4-related neuromuscular disease, findings that will guide TRPV4 therapeutics development.

biophysics↗

bioRxiv2023

PIF4 promotes water use efficiency during fluctuating light and drought resistance in rice

Molecular mechanism of intrinsic water use efficiency (iWUE) during fluctuating light (FL) was rarely understood. In this study, we investigated five parameters of iWUE under FL in 200 Minicore rice accessions. Among them, a novel trait, WUEFL (averaged iWUE during FL) has highest SNP heritability in these parameters. GWAS identifies six candidate genes, and PIF4 is highly expressed in high iWUEFL rice subgroup. Nine SNPs were significantly associated with iWUEFL, and v3 SNP located at -1,075 bp of PIF4 promoter shows highest sensitives to light. Deletion of v3 in a rice cultivar, WYG7 (PIF4v3m) leads to [~]20% reduction in iWUEFL, and overexpressing PIF4 causes 25% increase in iWUEFL under DS. There are 85% reduction in adenosine 3,5-diphosphate (PAP) amounts together with 73% increase in SAL1 gene abundance in PIF4v3m than WYG7. PIF4 transcriptionally repress and activate SAL1 and NHX1, respectively, through binding to G-box motifs of the two genes, which leads to 16% reduction and 5% increase in iWUEFL in co-overexpression rice lines of PIF4-SAL1 and PIF4-NHX1, respectively, relative to PIF4-OE under DS. We proposed that PIF4 promotes iWUEFL and stomatal adjustment via targeting the G-box motif of SAL1 and NHX1 genes during FL, eventually facilitating to drought resistance.

plant biology↗

bioRxiv2023

Dominant Role of Stochastic Processes in Soil Fungal Communities in Pioneer Forests at a Regional Scale

Soil fungal community assembly is driven by deterministic and stochastic processes. However, the contribution of these mechanisms to structure the composition of fungal communities of forest soils at the regional scale is poorly known. Here, we investigate the relative importance of deterministic and stochastic processes on fungal community composition by rDNA ITS metabarcoding in a Populus davidiana pioneer forests along spatial-temporal gradients. We also assessed the impact of elevation and seasonality. The soil fungal richness of P. davidiana pioneer forests was significantly affected by elevation and less affected by season. Similarly, the variation in the fungal community composition according to the elevation was greater than the effect of seasonality. The fungal community composition showed a significant distance-decay relationship. Variation partitioning analysis showed that plant variables explained the soil fungal community variation. Through null model analysis, we found that stochastic processes were dominant in the soil fungal community assembly. However, the relative importance of ecological processes, including dispersal, selection, and drift, was not consistent across the four soil fungal community assemblies. In addition, the undominated fraction (including weak selection, weak dispersal, diversification and drift) had a high relative contribution to the soil fungal community assembly process in the P. davidiana pioneer forest. In summary, our results demonstrated that plant variables and the undominated fraction dominate the deterministic and stochastic processes driving soil fungal community assemblies in a P. davidiana pioneer forest at the regional scale, which provides new perspectives for the regional scale studies of soil fungi. IMPORTANCEElevation and seasonality are important factors driving the composition of soil microbiota. Due to the tight interactions of soil fungi with their host trees in forest ecosystems, the spatial variation of soil fungal community is often linked to the variation in the composition of dominant tree species. We compared the responses of soil fungal communities to seasonal and spatial changes at four levels in a temperate poplar forest dominated by a single tree species under elevation changes. Elevation had a higher impact than seasonality on the soil fungal beta diversity. Even when the shift in dominant tree species was limited, vegetation factors still impact soil fungal community variations. The dominant role of homogeneous selection and drift in fungal community assemblies, except for ectomycorrhizal fungi, was further discovered.

microbiology↗

bioRxiv2023

A PARP inhibitor, rucaparib, improves cardiac dysfunction in ADP-ribose-acceptor hydrolase 3 (Arh3) deficiency

AimsPatients with ADP-ribose-acceptor hydrolase 3 (ARH3) deficiency exhibit stress-induced childhood-onset neurodegeneration with ataxia and seizures (CONDSIAS). ARH3 degrades protein-linked poly(ADP- ribose) (PAR) synthesized by poly(ADP-ribose)polymerase (PARP)-1 during oxidative stress, leading to cleavage of the ADP-ribose linked to protein. ARH3 deficiency leads to excess accumulation of PAR, resulting in PAR-dependent cell death or parthanatos. Approximately one-third of patients with homozygous mutant ARH3 die from cardiac arrest, which has been described as neurogenic, suggesting that ARH3 may play an important role in maintaining myocardial function. To address this question, cardiac function was monitored in Arh3-knockout (KO) and - heterozygous (HT) mice. Methods and resultsArh3-KO male mice displayed cardiac hypertrophy by histopathology and decreased cardiac contractility assessed by MRI. In addition, both genders of Arh3-KO and -HT mice showed decreased cardiac contractility by dobutamine stress test assessed by echocardiography. A direct role of ARH3 on myocardial function was seen with a Langendorff-perfused isolated heart model. Arh3-KO male mouse hearts showed decreased post-ischemic rate pressure products, increased size of ischemia-reperfusion (IR) infarcts, and elevated PAR levels. Consistently, in vivo IR injury showed enhanced infarct size in Arh3-KO mice in both genders. In addition, Arh3-HT male mice showed increased size of in vivo IR infarcts. Treatment with an FDA-approved PARP inhibitor, rucaparib, improved cardiac contractility during dobutamine-induced stress and exhibited reduced size of in vivo IR infarcts. To understand better the role of ARH3, CRISPR-Cas9 was used to generate different Arh3 genotypes of myoblasts and myotubes. Incubation with H2O2 decreased viability of Arh3-KO and -HT myoblasts and myotubes, resulting in PAR-dependent cell death that was reduced by PARP inhibitors or by transfection with the Arh3 gene. ConclusionARH3 regulates PAR homeostasis in myocardium to preserve function and protect against oxidative stress; PARP inhibitors reduce the myocardial dysfunction seen with Arh3 mutations. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=159 SRC="FIGDIR/small/527369v1_ufig1.gif" ALT="Figure 1"> View larger version (57K): org.highwire.dtl.DTLVardef@a76514org.highwire.dtl.DTLVardef@1dd3184org.highwire.dtl.DTLVardef@ddfd26org.highwire.dtl.DTLVardef@16e0cd_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2023

Taxonomical and ontological analysis of verified natural and laboratory human coronavirus hosts

To fully understand COVID-19, it is critical to identify and analyze all the possible hosts of SARS-CoV-2 (the pathogen of COVID-19) and compare them with the hosts of other human coronaviruses. In this study, we collected, annotated, and performed taxonomical and ontological analysis of all the reported and verified hosts for all human coronaviruses including SARS-CoV, MERS-CoV, SARS-CoV-2, and four others that cause the common cold. A total of 37 natural hosts and 19 laboratory animal hosts of host human coronaviruses were identified based on experimental or clinical evidence. Our taxonomical ontology-based analysis found that all the verified susceptible natural and laboratory animals belong to therian mammals. Specifically, these 37 natural therian hosts include one wildlife marsupial mammal (i.e., Didelphis virginiana) and 36 Eutheria mammals (a.k.a. placental mammals). The 19 laboratory animal hosts are also classified as placental mammals. While several non-therian animals (including snake, housefly, zebrafish) were reported to be likely SARS-CoV-2 hosts, our analysis excluded them due to the lack of convincing evidence. Genetically modified mouse models with human Angiotensin-converting enzyme 2 (ACE2) or dipeptidyl peptidase-4 (DPP4) protein were more susceptible to virulent human coronaviruses with clear symptoms. Coronaviruses often became more virulent and adaptive in the mouse hosts after a series of viral passages in the mice. To support knowledge standardization and analysis, we have also represented the annotated host knowledge in the Coronavirus Infectious Disease Ontology (CIDO) and provided ways to automatically query the knowledge.

bioinformatics↗

bioRxiv2023

Spin-coupled electron densities of iron-sulfur cluster imaged by in situ serial Laue diffraction

Iron-sulfur clusters are inorganic cofactors found in many proteins involved in fundamental biological processes including DNA processing. The prokaryotic DNA repair enzyme PhrB, a member of the protein family of cryptochromes and photolyases, carries a four-iron-four-sulfur cluster [4Fe4S] in addition to the catalytic cofactor flavin adenine dinucleotide (FAD) and a second pigment 6,7-dimethyl-8-ribityllumazine (DMRL). The light-induced redox reactions of this multi-cofactor protein complex were recently shown as two interdependent photoreductions of FAD and DMRL mediated by the [4Fe4S] cluster functioning as an electron cache to hold a fine balance of electrons. Here, we apply the more traditional temperature-scan cryo-trapping technique in protein crystallography and the newly developed technology of in situ serial Laue diffraction at room temperature. These diffraction methods in dynamic crystallography enable us to capture strong signals of electron density changes in the [4Fe4S] cluster that depict quantized electronic movements. The mixed valence layers of the [4Fe4S] cluster due to spin coupling and their dynamic responses to light illumination are observed directly in our difference maps between its redox states. These direct observations of the quantum effects in a protein bound iron-sulfur cluster have thus opened a window into the mechanistic understanding of metal clusters in biological systems.

biophysics↗

bioRxiv2023

DPHL v2: An updated and comprehensive DIA pan-human assay library for quantifying more than 14,000 proteins.

A comprehensive pan-human spectral library is critical for biomarker discovery using mass spectrometry (MS)-based proteomics. DPHL v1, a previous pan-human library built from 1096 data-dependent acquisition (DDA) MS data of 16 human tissue types, allows quantifying 10,943 proteins. However, a major limitation of DPHL v1 is the lack of semi-tryptic peptides and protein isoforms, which are abundant in clinical specimens. Here, we generated DPHL v2 from 1608 DDA-MS data acquired using Orbitrap mass spectrometers. The data included 586 DDA-MS newly acquired from 17 tissue types, while 1022 files were derived from DPHL v1. DPHL v2 thus comprises data from 24 sample types, including several cancer types (lung, breast, kidney, and prostate cancer, among others). We generated four variants of DPHL v2 to include semi-tryptic peptides and protein isoforms. DPHL v2 was then applied to a publicly available colorectal cancer dataset with 286 DIA-MS files. The numbers of identified and significantly dysregulated proteins increased by at least 21.7% and 14.2%, respectively, compared with DPHL v1. Our findings show that the increased human proteome coverage of DPHL v2 provides larger pools of potential protein biomarkers.

bioinformatics↗

bioRxiv2023

Decapping factor Dcp2 controls mRNA abundance and translation to adjust metabolism and filamentation to nutrient availability

Degradation of most yeast mRNAs involves decapping by Dcp1/Dcp2. DEAD-box protein Dhh1 has been implicated as an activator of decapping, in coupling codon non-optimality to enhanced degradation, and as a translational repressor, but its functions in cells are incompletely understood. RNA-Seq analyses coupled with CAGE sequencing of all capped mRNAs revealed increased abundance of hundreds of mRNAs in dcp2{Delta} cells that appears to result directly from impaired decapping rather than elevated transcription, which was confirmed by ChIP-Seq analysis of RNA Polymerase II occupancies genome-wide. Interestingly, only a subset of mRNAs requires Dhh1 for targeting by Dcp2, and also generally requires the other decapping activators Pat1, Lsm2, Edc3 or Scd6; whereas most of the remaining transcripts utilize NMD factors for Dcp2-mediated turnover. Neither inefficient translation initiation nor stalled elongation appears to be a major driver of Dhh1-enhanced mRNA degradation. Surprisingly, ribosome profiling revealed that dcp2{Delta} confers widespread changes in relative TEs that generally favor well-translated mRNAs. Because ribosome biogenesis is reduced while capped mRNA abundance is increased by dcp2{Delta}, we propose that an increased ratio of mRNA to ribosomes increases competition among mRNAs for limiting ribosomes to favor efficiently translated mRNAs in dcp2{Delta} cells. Interestingly, genes involved in respiration or utilization of alternative carbon or nitrogen sources are derepressed, and both mitochondrial function and cell filamentation (a strategy for nutrient foraging) are elevated by dcp2{Delta}, suggesting that mRNA decapping sculpts gene expression post-transcriptionally to fine-tune metabolic pathways and morphological transitions according to nutrient availability.

molecular biology↗

bioRxiv2023

Dihydroxy-Metabolites of Dihomo-gamma-linolenic Acid Drive Ferroptosis- Mediated Neurodegeneration

Even after decades of research, the mechanism of neurodegeneration remains understudied, hindering the discovery of effective treatments for neurodegenerative diseases. Recent reports suggest that ferroptosis could be a novel therapeutic target for neurodegenerative diseases. While polyunsaturated fatty acid (PUFA) plays an important role in neurodegeneration and ferroptosis, how PUFAs may trigger these processes remains largely unknown. PUFA metabolites from cytochrome P450 and epoxide hydrolase metabolic pathways may modulate neurodegeneration. Here, we test the hypothesis that specific PUFAs regulate neurodegeneration through the action of their downstream metabolites by affecting ferroptosis. We find that the PUFA, dihomo gamma linolenic acid (DGLA), specifically induces ferroptosis-mediated neurodegeneration in dopaminergic neurons. Using synthetic chemical probes, targeted metabolomics, and genetic mutants, we show that DGLA triggers neurodegeneration upon conversion to dihydroxyeicosadienoic acid through the action of CYP-EH, representing a new class of lipid metabolite that induces neurodegeneration via ferroptosis.

neuroscience↗

bioRxiv2022

Mapping splice QTLs reveals distinct transcriptional and post-transcriptional regulatory variation of gene expression in pigs

BackgroundAlternative splicing is an important step in gene expression, generating multiple isoforms for the same genes and greatly expanding the diversity of proteomes. Genetic variation in alternative splicing contributes to phenotypic diversity in natural populations. However, the genetic basis of variation in alternative splicing in livestock animals including pigs remains poorly understood. ResultsIn this study, using a Duroc x Pietrain F2 pig population, we performed genome-wide analysis of alternative splicing estimated from stranded RNA-Seq data in skeletal muscle. We characterized the genetic architecture of alternative splicing and compared its basic features with overall gene expression. We detected a large number of novel alternative splicing events that were not previously annotated. We found heritability of quantitative alternative splicing scores (percent spliced in or PSI) to be lower than that of overall gene expression. In addition, heritabilities showed little correlation between alternative splicing and overall gene expression. Finally, we mapped expression QTLs (eQTLs) and splice QTLs (sQTLs) and found them to be largely non-overlapping. ConclusionsOur results suggest that regulatory variation exists at multiple levels and that their genetic controls are distinct, offering opportunities for genetic improvement.

genomics↗