Biology subjects

Yu, L.

Publications and source records attributed to Yu, L..

At least 145 records · Page 8Linked to original sources

bioRxiv2024

CRISPR screens reveal convergent targeting strategies against evolutionarily distinct chemoresistance in cancer

Resistance to chemotherapy has been a major hurdle that limits therapeutic benefits for many types of cancer. Here we systematically identify genetic drivers underlying chemoresistance by performing 30 genome-scale CRISPR knockout screens for seven chemotherapeutic agents in multiple cancer cells. Chemoresistance genes vary between conditions primarily due to distinct genetic background and mechanism of action of drugs, manifesting heterogeneous and multiplexed routes towards chemoresistance. By focusing on oxaliplatin and irinotecan resistance in colorectal cancer, we unravel that evolutionarily distinct chemoresistance can share consensus vulnerabilities identified by 26 second-round CRISPR screens with druggable gene library. We further pinpoint PLK4 as a therapeutic target to overcome oxaliplatin resistance in various models via genetic ablation or pharmacological inhibition, highlighting a single-agent strategy to antagonize evolutionarily distinct chemoresistance. Our study not only provides resources and insights into the molecular basis of chemoresistance, but also proposes potential biomarkers and therapeutic strategies against such resistance.

cancer biology↗

bioRxiv2024

Humoral immunogenicity comparison of XBB and JN.1 in human infections

The continuous evolution of SARS-CoV-2, particularly the emergence of the BA.2.86/JN.1 lineage replacing XBB lineages, necessitates re-evaluation of current vaccine compositions. Here, we provide a comprehensive analysis of the humoral immune response to XBB and JN.1 human exposures, emphasizing the need for JN.1-lineage-based boosters. We demonstrate the antigenic distinctiveness of XBB and JN.1 lineages in SARS-CoV-2-naive individuals but not in those with prior vaccinations or infections, and JN.1 infection elicits superior plasma neutralization titers against its subvariants. We highlight the strong immune evasion and receptor binding capability of KP.3, supporting its foreseeable prevalence. Extensive analysis of the BCR repertoire, isolating [~]2000 RBD-specific monoclonal antibodies (mAbs) with their targeting epitopes characterized by deep mutational scanning (DMS), underscores the systematic superiority of JN.1-elicited memory B cells (MBCs). Notably, Class 1 IGHV3-53/3-66-derived neutralizing antibodies (NAbs) contribute majorly within wildtype (WT)-reactive NAbs against JN.1. However, KP.2 and KP.3 evade a substantial subset of them, even those induced by JN.1, advocating for booster updates to KP.3 for optimized enrichment. JN.1-induced Omicron-specific antibodies also demonstrate high potency across all Omicron lineages. Escape hotspots of these NAbs have mainly been mutated in Omicron RBD, resulting in higher immune barrier to escape, considering the probable recovery of previously escaped NAbs. Additionally, the prevalence of broadly reactive IGHV3-53/3-66- encoding antibodies and MBCs, and their capability of competing with all Omicron-specific NAbs suggests their inhibitory role on the de novo activation of Omicron-specific naive B cells, potentially explaining the heavy immune imprinting in mRNA-vaccinated individuals. These findings delineate the evolving antibody response to Omicron antigenic shift from XBB to JN.1, and highlight the importance of developing JN.1 lineage, especially KP.3-based vaccine boosters, to enhance humoral immunity against current and future SARS-CoV-2 variants.

immunology↗

bioRxiv2024

A generalized framework to identify SARS-CoV-2 broadly neutralizing antibodies

Monoclonal antibodies (mAbs) targeting the SARS-CoV-2 receptor-binding domain (RBD) are used to treat and prevent COVID-19. However, the rapid evolution of SARS-CoV-2 drives continuous escape from therapeutic mAbs. Therefore, the ability to identify broadly neutralizing antibodies (bnAbs) against future variants is needed. Here, we use deep mutational scanning (DMS) to predict viral RBD evolution and to select for mAbs neutralizing both existing and prospective variants. A retrospective analysis of 1,103 SARS-CoV-2 wildtype-elicited mAbs shows that this method can increase the probability of identifying effective bnAbs against the XBB.1.5 strain from 1% to 40% in an early pandemic setup. Among these bnAbs, BD55-1205 exhibited potent activity against all tested variants. Cryo-EM structural analyses revealed the receptor mimicry of BD55-1205, explaining its broad reactivity. Delivery of mRNA-LNPs encoding BD55-1205-IgG in mice resulted in ~5,000 serum NT50 against XBB.1.5, HK.3.1, and JN.1 variants. Combining bnAb identification using viral evolution prediction with the versatility of mRNA delivery technology can enable rapid development of next-generation antibody-based countermeasures against SARS-CoV-2 and potentially other pathogens with pandemic potential.

immunology↗

bioRxiv2024

Natural variation in salt-induced changes in root:shoot ratio reveals SR3G as a negative regulator of root suberization and salt resilience in Arabidopsis

Soil salinity is one of the major threats to agricultural productivity worldwide. Salt stress exposure alters root and shoot growth rates, thereby affecting overall plant performance. While past studies have extensively documented the effect of salt stress on root elongation and shoot development separately, here we take an innovative approach by examining the coordination of root and shoot growth under salt stress conditions. Utilizing a newly developed tool for quantifying the root:shoot ratio in agar-grown Arabidopsis seedlings, we found that salt stress results in a loss of coordination between root and shoot growth rates. We identify a specific gene cluster encoding domain-of-unknown-function 247 (DUF247), and characterize one of these genes as Salt Root:shoot Ratio Regulator Gene (SR3G). Further analysis elucidates the role of SR3G as a negative regulator of salt stress tolerance, revealing its function in regulating shoot growth, root suberization, and sodium accumulation. We further characterize that SR3G expression is modulated by WRKY75 transcription factor, known as a positive regulator of salt stress tolerance. Finally, we show that the salt stress sensitivity of wrky75 mutant is completely diminished when it is combined with sr3g mutation. Together, our results demonstrate that utilizing root:shoot ratio as an architectural feature leads to the discovery of new stress resilience gene. The studys innovative approach and findings not only contribute to our understanding of plant stress tolerance mechanisms but also open new avenues for genetic and agronomic strategies to enhance crop environmental resilience.

plant biology↗

bioRxiv2024

SMARCA2 and SMARCA4 participate in DNA damage repair

SMARCA2 and SMARCA4 (SMARCA2/4) are paralogs and act as the key enzymatic subunits in the SWI/SNF complex for chromatin remodeling. However, the role of SMARCA2/4 in DNA damage response remains unclear. Here, we show that SMARCA2/4 relocate to DNA lesions in response to DNA damage, which requires their ATPase activities. Moreover, these ATPase activities are also required for the relocation of other subunits in the SWI/SNF complex to DNA lesions. Interestingly, the relocation of SMARCA2/4 is independent of {gamma}H2AX, ATM, ATR, p300/CBP, or PARP1/2, indicating that it may directly recognize DNA lesions as a DNA damage sensor. Lacking SMARCA2/4 prolongs the retention of {gamma}H2AX, RNF8 and BRCA1 at DNA lesions and impairs RAD51-dependent homologous recombination repair. Moreover, the treatment of SMARCA2/4 inhibitor sensitizes tumor cells to PARP inhibitor treatment. Collectively, this study reveals SMARCA2/4 as a DNA damage repair factor for double-strand break repair.

cell biology↗

bioRxiv2024

CPT1A Mediates Radiation Sensitivity in Colorectal Cancer

The prevalence and mortality rates of colorectal cancer (CRC) are increasing worldwide. Radiation resistance hinders radiotherapy, a standard treatment for advanced CRC, leading to local recurrence and metastasis. Elucidating the molecular mechanisms underlying radioresistance in CRC is critical to enhance therapeutic efficacy and patient outcomes. Bioinformatic analysis and tumour tissue examination were conducted to investigate the CPT1A mRNA and protein levels in CRC and their correlation with radiotherapy efficacy. Furthermore, lentiviral overexpression and CRISPR/Cas9 lentiviral vectors, along with in vitro and in vivo radiation experiments, were used to explore the effect of CPT1A on radiosensitivity. Additionally, transcriptomic sequencing, molecular biology experiments, and bioinformatic analyses were employed to elucidate the molecular mechanisms by which CPT1A regulates radiosensitivity. CPT1A was significantly downregulated in CRC and negatively correlated with responsiveness to neoadjuvant radiotherapy. Functional studies suggested that CPT1A mediates radiosensitivity, influencing reactive oxygen species (ROS) scavenging and DNA damage response. Transcriptomic and molecular analyses highlighted the involvement of the peroxisomal pathway. Mechanistic exploration revealed that CPT1A downregulates the FOXM1-SOD1/SOD2/CAT axis, moderating cellular ROS levels after irradiation and enhancing radiosensitivity. CPT1A downregulation contributes to radioresistance in CRC by augmenting the FOXM1-mediated antioxidant response. Thus, CPT1A is a potential biomarker of radiosensitivity and a novel target for overcoming radioresistance, offering a future direction to enhance CRC radiotherapy.

cancer biology↗

bioRxiv2024

CircRNA-Pro: A Novel Toolkit for High-Precision Detection of Differentially Expressed Circular RNAs and Translatable Circular RNAs

With the increasing discovery of circular RNAs (circRNAs) and their critical roles in gene regulation and disease progression, there is a growing need for more accurate and efficient tools for circRNAs research. In response, we have developed an integrated software suite specifically for circRNAs. This all-in-one tool specializes in detecting differentially expressed circRNAs, including those with the potential to be translated into proteins, and allows for comparing against relevant databases, thereby enabling comprehensive circRNA profiling and annotation. To enhance the accuracy in detecting differentially expressed circRNAs, we incorporated three different software algorithms and cross-validated their results through mutual verification. Additionally, this toolkit improves the effectiveness in identifying translatable circRNAs by optimizing Ribo-seq alignment and verifying against public circRNA databases. The performance of circRNA-pro has been evaluated through its application to public RNA-seq and Ribo-seq datasets on breast cancer and SARS-CoV-2 infected cells, and the results obtained have been validated against previous literature and databases. Overall, our integrated toolkit provides a reliable workflow for circRNA research, facilitating insights into their diverse roles across life sciences.

bioinformatics↗

bioRxiv2024

Engineered Migrasomes: A Robust, Thermally Stable Vaccination Platform

The increasing ability of pathogens and tumor cells to evade immune detection underscores the urgent need for novel vaccine platforms leveraging diverse biological mechanisms. Additionally, logistical challenges associated with cold-chain transportation significantly limit vaccine accessibility, especially in resource-limited regions. Recently, we identified migrasomes, specialized organelles generated during cell migration, which are inherently stable and enriched with immune-modulating molecules. To address the low yield of natural migrasomes, we engineered migrasome-like vesicles (eMigrasomes) using hypotonic shock combined with cytoskeletal disruption to enhance vesicle formation. The biogenesis of eMigrasomes relies on the core migrasome machinery, faithfully recapitulating the biophysical attributes of native migrasomes while significantly improving production efficiency. We demonstrate that eMigrasomes loaded with a model antigen elicit potent antibody responses and maintain structural integrity and immunogenic potential at room temperature. Furthermore, eMigrasomes displaying the SARS-CoV-2 Spike protein induce robust humoral immune responses, providing effective protection against viral infection. Our findings highlight the potential of utilizing migrasome biology and hypotonic shock-driven vesicle generation as an innovative, stable, and broadly accessible vaccine platform.

cell biology↗

bioRxiv2024

Multiomics Analysis Reveals Extensive Remodeling of the Extracellular Matrix and Cellular Metabolism Due to Plakophilin-2 Knockdown in Guinea Pigs

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a leading cause of sudden cardiac death (SCD) in young individuals, yet the mechanisms underlying its pathogenesis, particularly the role of plakophilin-2 (PKP2), remain incompletely understood. This study aimed to elucidate the profile of molecular and metabolic consequences of PKP2 knockdown in a guinea pig model of ARVC. We employed adeno-associated virus serotype 9 (AAV9) to deliver PKP2 shRNA, establishing a model that recapitulates key features of human ARVC, including right ventricular (RV) enlargement, sudden death, and cardiac lipid accumulation. Proteomic analysis revealed significant dysregulation of extracellular matrix (ECM) proteins, PI3K-Akt signaling, and energy metabolism in PKP2-deficient RVs. Metabolomic profiling further highlighted alterations in lipid metabolism and inter-metabolites of TCA cycle, with a notable shift towards fatty acid oxidation. These findings suggest that PKP2 deficiency triggers a cascade of molecular events leading to ECM remodeling, metabolic reconfiguration, and potential mitochondrial dysfunction, which may contribute to the development of ARVC. Our study provides novel insights into the early molecular mechanisms of ARVC and identifies potential therapeutic targets for this underexplored disease.

genetics↗

bioRxiv2024

Antigenicity assessment of SARS-CoV-2 saltation variant BA.2.87.1

The recent emergence of a SARS-CoV-2 saltation variant, BA.2.87.1, which features 65 spike mutations relative to BA.2, has attracted worldwide attention. In this study, we elucidate the antigenic characteristics and immune evasion capability of BA.2.87.1. Our findings reveal that BA.2.87.1 is more susceptible to XBB-induced humoral immunity compared to JN.1. Notably, BA.2.87.1 lacks critical escaping mutations in the receptor binding domain (RBD) thus allowing various classes of neutralizing antibodies (NAbs) that were escaped by XBB or BA.2.86 subvariants to neutralize BA.2.87.1, although the deletions in the N-terminal domain (NTD), specifically 15-23del and 136-146del, compensate for the resistance to humoral immunity. Interestingly, several neutralizing antibody drugs have been found to restore their efficacy against BA.2.87.1, including SA58, REGN-10933 and COV2-2196. Hence, our results suggest that BA.2.87.1 may not become widespread until it acquires multiple RBD mutations to achieve sufficient immune evasion comparable to that of JN.1.

immunology↗

bioRxiv2024

HTLV-1 infected T cells cause bone loss via small extracellular vesicles

Adult T cell leukemia (ATL), caused by infection with human T cell leukemia virus type 1 (HTLV-1), is often complicated by hypercalcemia and osteolytic lesions. Therefore, we studied the communication between patient-derived ATL cells (ATL-PDX) and HTLV-1 immortalized CD4+ T cell lines (HTLV/T) with osteoclasts and their effects on bone mass in mice. Intratibial inoculation of some HTLV/T lead to a profound local decrease in bone mass similar to marrow-replacing ATL-PDX, despite the fact that few HTLV/T cells persisted in the bone. To study the direct effect of HTLV/T and ATL-PDX on osteoclasts, supernatants were added to murine and human osteoclast precursors. ATL-PDX supernatants from hypercalcemic patients promoted formation of mature osteoclasts, while those from HTLV/T were variably stimulatory, but had largely consistent effects between human and murine cultures. Interestingly, this osteoclastic activity did not correlate with expression of osteoclastogenic cytokine RANKL, suggesting an alternative mechanism. HTLV/T and ATL-PDX produce small extracellular vesicles (sEV), known to facilitate HTLV-1 infection. We hypothesized that these sEV also mediate bone loss by targeting osteoclasts. We isolated sEV from both HTLV/T and ATL-PDX, and found they carried most of the activity found in supernatants. In contrast, sEV from uninfected activated T cells had little effect. Analysis of sEV (both active and inactive) by mass spectrometry and electron microscopy confirmed absence of RANKL and intact virus. Viral proteins Tax and Env were only present in sEV from the active, osteoclast-stimulatory group, along with increased representation of proteins involved in osteoclastogenesis and bone resorption. sEV injected over mouse calvaria in the presence of low dose RANKL caused more osteolysis than RANKL alone. Thus, HTLV-1 infection of T cells can cause release of sEV with strong osteolytic potential, providing a mechanism beyond RANKL production that modifies the bone microenvironment, even in the absence of overt leukemia.

cancer biology↗

bioRxiv2024

Rapid Identification of Genomic Alterations in Tumors affecting lymphocyte Infiltration (RIGATonI)

Tumor genomic alterations have been associated with altered tumor immune microenvironments and therapeutic outcomes. These studies raise a critical question: are there additional genomic variations altering the immune microenvironment in tumors that can provide insight into mechanisms of immune evasion? This question is the backbone of precision immuno-oncology. Current computational approaches to estimate immunity in bulk RNA sequencing (RNAseq) from tumors include gene set enrichment analysis and cellular deconvolution, but these techniques do not consider the spatial organization of lymphocytes or connect immune phenotypes with gene activity. Our new software package, Rapid Identification of Genomic Alterations in Tumors affecting lymphocyte Infiltration (RIGATonI), addresses these two gaps in separate modules: the Immunity Module and the Function Module. Using pathologist-reviewed histology slides and paired bulk RNAseq expression data, we trained a machine learning algorithm to detect high, medium, and low levels of immune infiltration (Immunity Module). We validated this technique using a subset of pathologist-reviewed slides not included in the training data, multiplex immunohistochemistry, flow cytometry, and digital staining of The Cancer Genome Atlas (TCGA). In addition to immune infiltrate classification, RIGATonI leverages another novel machine learning algorithm for the prediction of gain- and loss-of-function genomic alterations (Function Module). We validated this approach using clinically relevant and function-impacting genomic alterations from the OncoKB database. Combining these two modules, we analyzed all genomic alterations present in solid tumors in TCGA for their resulting protein function and immune phenotype. We visualized these results on a publicly available website. To illustrate RIGATonIs potential to identify novel genomic variants with associated altered immune phenotypes, we describe increased anti-tumor immunity in renal cell carcinoma tumors harboring 14q deletions and confirmed these results with previously published single-cell RNA sequencing. Thus, we present our R package and online database, RIGATonI: an innovative software for precision immuno-oncology research.

bioinformatics↗

bioRxiv2024

Engineering oncogenic hotspot mutations on SF3B1 via CRISPR-directed PRECIS mutagenesis

SF3B1 is the most recurrently mutated RNA splicing factor in cancer; However, its study has been hindered by a lack of disease-relevant cell line models. Here, we compared four genome engineering platforms to establish SF3B1mutant cell lines: CRISPR-Cas9 editing, AAV HDR editing, base editing (ABEmax, ABE8e), and prime editing (PE2, PE3, PE5Max). We showed that prime editing via PE5max achieved the most efficient SF3B1 K700E editing across a wide range of cell lines. We further refined our approach by coupling prime editing with a with a fluorescent reporter that leverages a SF3B1 mutation-responsive synthetic intron to mark prime edited cells. Calling this approach prime editing coupled intron-assisted selection (PRECIS), we then introduced the K700E hotspot mutation into two chronic lymphocytic leukemia (CLL) cell lines, HG-3 and MEC-1, and demonstrated that our PRECIS-engineered cells faithfully recapitulate the altered splicing and copy number variation (CNV) events frequently found in CLL patients with SF3B1 mutation. Our results showcase PRECIS as an efficient and generalizable method for engineering genetically faithful SF3B1 mutant models, shed new light on the role of SF3B1 mutation in cancer biology, and enables generation of novel SF3B1 mutant cell lines in any cellular context.

cancer biology↗

bioRxiv2024

Hist2Cell: Deciphering Fine-grained Cellular Architectures from Histology Images

Histology images, with low cost, are unleashing great power of predicting cellular phenotypes in tissue, thanks to the emerging spatial transcriptomics serving as annotations. Recent efforts aimed to predict individual gene expression, suffering from low accuracy and high variability, while no methods are tailored to predict fine-grained transcriptional cell types -the most critical phenotype. Here, we present Hist2Cell, a Vision Graph-Transformer framework, to accurately resolve fine-grained transcriptional cell types (up to 40 cell types) directly from histology images and further create cellular maps of diverse tissues at a customizable resolution. Specifically, trained on human lung and breast cancer spatial transcriptome datasets, Hist2Cell accurately predicts the abundance of each cell type across space in new patient samples with Pearson Correlation Coefficient of biological informative cell types over 0.80, and effectively capturing their colocalization directly from histology images. Moreover, without re-training, it robustly generalizes to large-scale histology cancer cohorts from TCGA, highlighting recurrent cell co-localization and supporting precise survival prediction by revealing distinct tissue micro-environments and insightful cell type-patient mortality relationship. Therefore, Hist2Cell enables cost-efficient histology analysis for large-scale studies of spatial biology and precise cancer prognosis in real-world clinical diagnostics.

bioengineering↗

bioRxiv2024

In vitro activity of cefiderocol against carbapenemase-producing and meropenem-nonsusceptible gram-negative bacteria collected in the Japan Antimicrobial Resistant Bacterial Surveillance (JARBS-GNR)

The treatment options available for infections caused by multidrug-resistant gram-negative pathogens are often limited. Cefiderocol (CFDC) is a novel siderophore cephalosporin that exhibits activity against multidrug-resistant gram-negative pathogens. Several studies have reported the in vitro activity of CFDC using clinical isolates from Europe, the United States, and China. However, no large-scale studies on the in vitro activities of CFDC have been conducted using all isolates with available genomic backgrounds based on whole-genome sequencing (WGS). We evaluated the antimicrobial activities of CFDC, ceftolozane/tazobactam (CTLZ/TAZ), imipenem-relebactam (IPM/REL), and ceftazidime/avibactam (CAZ/AVI) against carbapenemase-producing Enterobacterales, carbapenemase-non-producing meropenem-nonsusceptible Enterobacterales, and carbapenemase-producing non-fermentative bacteria. We selected 603 isolates (528 Enterobacterales, 18 Pseudomonas aeruginosa, and 57 Acinetobacter spp.) from the recent surveillance of clinical isolates in Japan using WGS data. Among these, 97.7% (300/307 strains) of carbapenemase-producing Enterobacterales, 100% (18/18 strains) of carbapenemase-producing P. aeruginosa, and 91.2% (52/57 strains) of carbapenemase-producing Acinetobacter spp. were susceptible to CFDC, showing better antimicrobial activity than the other antimicrobial agents evaluated in this study. In addition, CFDC was highly effective against class A, B, and D {beta}-lactamase harboring isolates when compared to the other antimicrobial agents in this study. While {beta}-lactam antibiotics were essentially ineffective against CFDC-resistant Enterobacterales, minocycline was the most effective, and gentamicin and amikacin were also effective. This is the first large-scale study to systematically demonstrate the efficacy of CFDC using carbapenemase-producing strains with transparent genomic backgrounds.

microbiology↗

bioRxiv2024

The long noncoding RNA lnc-FANCI-2 restricts RAS signaling and phosphorylation of Akt and Erk in HPV16-infected cervical cancer cells

We recently discovered the expression of a long noncoding RNA, lnc-FANCI-2, coinciding with cervical lesion progression from CIN1, CIN2-3 to cervical cancer. Viral E7 of high-risk HPVs and host transcription factor YY1 are two major factors promoting lnc-FANCI-2 expression. To explore possible roles of lnc-FANCI-2 in HPV-induced cervical carcinogenesis, we ablated the expression of lnc-FANCI-2 in the HPV16-positive cervical cancer cell line, CaSki. Knock-out (KO) single cell clones expressed HPV16 oncogenes normally but displayed altered cell morphology and proliferation when compared with the parental cells. Proteomic profiling of cytosolic and secreted proteins from the parental and KO cells showed that lnc-FANCI-2 regulates expression of a subset of cell soluble receptors responsible for cell signaling, epithelial mesenchymal transition, and IFN responses. RNA-seq analyses revealed that, relative to the parental cells, lnc-FANCI-2 KO cells exhibited significantly increased RAS signaling but decreased IFN pathways. In the KO cells, phosphorylated Akt and Erk1/2, two important RAS pathway effectors, were increased more than 3-fold, accompanied by increase of IGFBP3, MCAM, VIM, and CCND2 (cyclin D2) and decrease of RAC3 expression. High levels of lnc-FANCI-2 and lower levels of MCAM in cervical cancer patients are associated with improved survival. We found that lnc-FANCI-2 interacts specifically with 32 host proteins, including H13, HNRH1, K1H1, MAP4K4, and RNPS1, and knockdown of MAP4K4 in CaSki cells led to an increase of phosphorylation of Erk1/2 and somewhat Akt. In summary, a key function of lnc-FANCI-2 is to intrinsically regulate RAS signaling to impact cervical lesion progression and affect cervical cancer prognosis. SignificanceExpression of lnc-FANCI-2 is related to cervical lesion progression. Knock-out (KO) or knock-down (KD) of lnc-FANCI-2 expression in HPV16-positive cervical cancer cells CaSki significantly increases RAS signaling, phosphorylation of Akt and Erk1/2, and the epithelial mesenchymal transition factors. lnc-FANCI-2 KO also regulates the expression of a subset of cell soluble receptor proteins IGFBP3 and MCAM. A high level of lnc-FANCI-2 and lower level of MCAM in cervical cancer patients are associated with improved survival. lnc-FANCI-2 in CaSki cells interacts specifically with 32 host proteins, including MAP4K4. KD of MAP4K4 expression in CaSki cells led to an increase in phosphorylation of Erk1/2 and Akt. Thus, one lnc-FANCI-2 function is to intrinsically regulate RAS signaling to impact cervical lesion progression.

cancer biology↗

bioRxiv2024

XAPT and XLPT enzymes modify the glucuronic acid side chains of tissue-specific xylans in Arabidopsis and Eucalyptus

* Polysaccharide structural complexity not only influences cell wall strength and extensibility, but also hinders pathogenic and biotechnological attempts to saccharify the wall. In certain species and tissues, glucuronic acid side chains on xylan exhibit arabinopyranose or galactose decorations whose genetic and evolutionary basis is completely unknown, impeding efforts to understand their function and engineer wall digestibility. * Genetics and polysaccharide profiling were used to identify the responsible loci in Arabidopsis and Eucalyptus from proposed candidates, while phylogenies uncovered a shared evolutionary origin. GH30-family endo-glucuronoxylanase activities were analysed by electrophoresis and their differing specificities were rationalised by phylogeny and structural analysis. * The newly identified xylan arabinopyranosyltransferases comprise an overlooked subfamily in the GT47-A family of Golgi glycosyltransferases, previously assumed to comprise mainly xyloglucan galactosyltransferases, highlighting an unanticipated adaptation of both donor and acceptor specificities. Further neofunctionalisation has produced a Myrtaceae-specific xylan galactosyltransferase. Simultaneously, GH30 endo-glucuronoxylanases have convergently adapted to overcome these decorations, suggesting a role for these structures in defence. The differential expression of glucuronoxylan-modifying genes across Eucalyptus tissues, however, hints at further functions. * Our results demonstrate the rapid adaptability of biosynthetic and degradative carbohydrate-active enzyme activities, providing insight into a plant-pathogen arms race and facilitating plant cell wall biotechnological utilisation.

plant biology↗

bioRxiv2024

An inappropriate decline in ribosome levels drives a diverse set of neurodevelopmental disorders

Many neurodevelopmental defects are linked to perturbations in genes involved in housekeeping functions, such as those encoding ribosome biogenesis factors. However, how reductions in ribosome biogenesis can result in tissue and developmental specific defects remains a mystery. Here we describe new allelic variants in the ribosome biogenesis factor AIRIM primarily associated with neurodevelopmental disorders. Using human cerebral organoids in combination with proteomic analysis, single-cell transcriptome analysis across multiple developmental stages, and single organoid translatome analysis, we identify a previously unappreciated mechanism linking changes in ribosome levels and the timing of cell fate specification during early brain development. We find ribosome levels decrease during neuroepithelial differentiation, making differentiating cells particularly vulnerable to perturbations in ribosome biogenesis during this time. Reduced ribosome availability more profoundly impacts the translation of specific transcripts, disrupting both survival and cell fate commitment of transitioning neuroepithelia. Enhancing mTOR activity by both genetic and pharmacologic approaches ameliorates the growth and developmental defects associated with intellectual disability linked variants, identifying potential treatment options for specific brain ribosomopathies. This work reveals the cellular and molecular origins of protein synthesis defect-related disorders of human brain development. HighlightsO_LIAIRIM variants reduce ribosome levels specifically in neural progenitor cells. C_LIO_LIInappropriately low ribosome levels cause a transient delay in radial glia fate commitment. C_LIO_LIReduced ribosome levels impair translation of a selected subset of mRNAs. C_LIO_LIGenetic and pharmacologic activation of mTORC1 suppresses AIRIM-linked phenotypes. C_LI

developmental biology↗