Biology subjects

Tedeschi, F.

Publications and source records attributed to Tedeschi, F..

11 recordsLinked to original sources

bioRxiv2026

Hog1/p38 and ZAKα drive Shwachman-Diamond syndrome and provide targets to improve cell growth

Shwachman-Diamond syndrome (SDS) is a ribosomopathy characterized by neutropenia, pancreatic insufficiency, skeletal defects, and predisposition to leukemia. Most cases result from biallelic SBDS mutations that impairing 80S ribosome and polysome assembly. In yeast lacking SDO1 (the SBDS ortholog), growth slows dramatically and the p38 ortholog Hog1 signaling is elevated by multiple types of stress. SBDS-deficient HeLa cells exhibited reduced proliferation and slowed cell cycling. The p38 kinase was constitutively activated in SBDS mutants and SDS patient-derived blood cells. Because ZAK detects ribosome dysfunction, its activation links ribosomal defects to stress kinase pathways in SDS. Suppressing p38 or its upstream activator ZAK restored cell growth and reduced stress signaling. These findings reveal an evolutionarily conserved-independent mechanism via p38 drives SDS pathophysiology and identifies stress kinases as potential therapeutic targets for ribosomal dysfunction.

cell biology↗

bioRxiv2026

Characterization of novel cytoplasmic roles for the N-terminal methyltransferase NRMT1

N-terminal methylation of proteins by the trimethylase NRMT1 plays important roles in oncogenesis, development, and aging. As N-terminal methylation has frequently been shown to regulate protein-DNA interactions, and many NRMT1 substrates are transcription factors or regulators of chromatin structure, previous research has focused on how transcriptional regulation by NRMT1 affects cell growth and differentiation. However, we have recently identified a new, cytoplasmic role for NRMT1, inhibiting the eukaryotic elongation factor 1 alpha (eEF1A) methyltransferase METTL13, which indicates NRMT1 could also be acting as a translational regulator. Here we further explore NRMT1 cytoplasmic functions and show that, unlike previously thought, NRMT1 can methylate substrates in the cytoplasm. We also show that while many of these substrates remain bound to NRMT1, it can also interact with a number of non-target ribosomal proteins and proteins associated with the endoplasmic reticulum (ER). To confirm NRMT1 interaction with the ribosome, we performed polysome profiling, which showed a portion of NRMT1 co-migrates with the 40S and 60S subunits but not with actively translating polysomes, indicating NRMT1 may play an early role in translation. To see if NRMT1 was affecting target mRNA selection of ribosomes, we also performed ribosome-sequencing experiments in proliferating and differentiating C2C12 mouse myoblasts. These results show a striking upregulation of translation of soluble proteins with NRMT1 loss and corresponding decrease in translation of transmembrane and signal sequence-containing proteins. We now propose a model where NRMT1 regulates the translation of transmembrane and secreted proteins by facilitating interactions between the ribosome and the ER.

biochemistry↗

bioRxiv2025

Loss of NRMT1 allows expression of multiple differentiation pathways and alters transcription of secreted proteins in C2C12 myoblasts

Muscle stem cells (satellite cells) retain their identity and function through expression of the paired homeobox transcription factor PAX7. PAX7 is able to both stimulate satellite cell proliferation and activate target genes involved in establishing myogenic identity, including myogenic factor 5 (MYF5) and the other myogenic regulatory factors (MRFs). Upregulation of the MRFs promotes commitment to the muscle lineage by initiating withdrawal from the cell cycle, upregulating expression of muscle-specific transcripts, and directing myoblast fusion. We have previously shown that knockout of the N-terminal methyltransferase NRMT1 in C2C12 mouse myoblasts results in significantly decreased Pax7 expression, an inability of the cells to differentiate into myotubes, and abnormal upregulation of osteogenic markers. Here, we use RNA-sequencing to more comprehensively determine how loss of NRMT1 affects the transcriptional profile of proliferating and differentiating C2C12 myoblasts. We see that upon inducing differentiation, NRMT1 knockout cells can downregulate cell cycle, DNA replication, and histone gene expression. Though they also have significantly downregulated Pax7 and Myf5 expression, other muscle-specific transcripts are significantly increased over wild type, indicating the muscle transcriptional program is not completely inhibited. However, signaling pathways involved in the differentiation of other types of mesenchymal and hematopoietic lineages are also increased with NRMT1 loss and expression of chemotactic genes is downregulated. Together, these data indicate that NRMT1 knockout cells can upregulate genes needed for cell cycle withdrawal and muscle specification but fail to suppress markers of other lineages and activate normal chemotactic signaling, which may lead to the observed differentiation phenotypes.

genomics↗

bioRxiv2025

RHD6LA regulates root hair responses to both symbionts and commensals

While intracellular symbiosis with rhizobia relies on Nod factor signaling through the conserved common symbiosis signaling pathway (CSSP), it remains unclear how legumes simultaneously manage interactions with commensal soil microbes. Using single cell RNA-sequencing, we show that commensal soil bacteria induce a Nod factor-independent transcriptional response in specific root hairs. This response is similar to the rhizobium response in the CSSP-deficient cyclops mutant, which is unable to accommodate rhizobia in root hair infection threads. Both responses include the nodulation gene NSP2 and a transcription factor, which we name ROOT HAIR DEFECTIVE 6 LIKE A (RHD6LA). We show that RHD6LA is required for facilitating infection thread formation in response to rhizobia and for preventing exaggerated root hair responses to commensal soil bacteria. The overlap between commensal and symbiotic signaling highlights the complexity of legume-microbe interactions at the root hair interface and suggests new mechanisms for microbial discrimination in rhizobium-responsive root hairs.

molecular biology↗

bioRxiv2025

Design of novel synthetic promoters to tune gene expression in T cells

Transcriptional control of transgene expression can be linked to dynamic changes in cellular states if this is accompanied by differential expression of transcription factors (TFs). Synthetic promoters (SPs) designed to respond to the desired TFs can provide this regulation with compactness, specificity, and orthogonality. T cells display differentially expressed TFs according to the functional state. In solid tumors, the highly immunosuppressive TME and the chronic exposure to antigens lead to a progression of T cells from a functional to a dysfunctional state known as exhaustion (Tex), in which their power against cancer cells is strongly compromised. Importantly, this transition is accompanied by a marked increase of several TFs, among other factors, that drive targeted genetic programs. Strategies to detect and mitigate Tex are extremely needed. Here, we design SPs that respond to TFs differentially expressed in activated and exhausted T cells to enable new classifiers of the functional/dysfunctional states. We developed a library of over 80 SPs responsive to 7 TFs. The SPs showed broad strength of activation of reporter genes or immunomodulatory molecules in HEK293 and Jurkat T cell lines. Moreover, using a transfer learning strategy we show SPs strength predictability. By combining SPs responding to different TFs, we created Boolean logic gates and implemented a feed-forward design that was previously shown to reduce noise in the OFF-state. Finally, as proof of principle, we demonstrate the dynamic activation of the NR4A2-responsive SP according to the T cell state in primary human CD8+ T cells. Collectively we present a sensing platform that provides a versatile tool to study and monitor the dynamic changes occurring in T cells. In perspective the biosensors coupled to therapeutic genes can be used to reprogram the TME and reinvigorate the T cell anti-tumoral functionality, preventing or reverting the exhausted phenotype. Graphical AbstractCreated with BioRender.com. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=108 SRC="FIGDIR/small/632034v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@136e147org.highwire.dtl.DTLVardef@22e5org.highwire.dtl.DTLVardef@f2e863org.highwire.dtl.DTLVardef@176c02c_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗

bioRxiv2024

Computational identification of small molecules for increased gene expression by synthetic circuits in mammalian cells

Engineering mammalian cells with synthetic circuits is leading the charge in next generation biotherapeutics and industrial biotech innovation. However, applications often depend on the cells productive capacity, which is limited by the finite cellular resources available. We have previously shown that cells engineered with incoherent feedforward loops (iFFL-cells) operate at higher capacity than those engineered with the open loop (OL). Here, we performed RNA-sequencing on cells expressing the iFFL and utilized DECCODE, an unbiased computational method, to match our data with thousands of drug-induced transcriptional profiles. DECCODE identified compounds that consistently enhance expression of both transiently and stably expressed genetic payloads across various experimental scenarios and cell lines, while also reducing external perturbations on integrated genes. Further, we show that drug treatment enhances the rate of AAV and lentivirus transduction, facilitating the prototyping of genetic devices for gene and cell therapies. Altogether, despite limiting intracellular resources is a pervasive, and strongly cell-dependent problem, we provide a versatile tool for a wide range of biomedical and industrial applications that demand enhanced productivity from engineered cells.

synthetic biology↗

bioRxiv2024

Modulation of ribosomal subunit associations by eIF6 is critical for mitotic exit and cancer progression.

Moderating the pool of active ribosomal subunits is critical for maintaining global translation rates. A factor crucial for modulating the 60S ribosomal subunits is eukaryotic translation initiation factor 6. Release of eIF6 from 60S is essential to permit 60S interactions with 40S. Here, using the N106S mutant of eIF6, we show that disrupting eIF6 interaction with 60S leads to an increase in vacant 80S. It further highlights a dichotomy in the anti-association activity of eIF6 that is distinct from its role in 60S biogenesis and shows that the nucleolar localization of eIF6 is not dependent on uL14-BCCIP interactions. Limiting active ribosomal pools markedly deregulates translation especially in mitosis and leads to chromosome segregation defects, mitotic exit delays and mitotic catastrophe. Ribo-Seq analysis of the eIF6-N106S mutant shows a significant downregulation in the translation efficiencies of mitotic factors and specifically transcripts with long 3'UTRs. eIF6-N106S mutation also limits cancer invasion, and this role is correlated with the overexpression of eIF6 only in high-grade invasive cancers suggesting that deregulation of eIF6 is probably not an early event in cancers. Thus, this study highlights the segregation of eIF6 functions and its role in moderating 80S availability for mitotic translation and cancer progression.

molecular biology↗

bioRxiv2022

Single-cell analysis maps distinct cellular responses to rhizobia and identifies the novel infection regulator SYMRKL1 in Lotus japonicus

Legume-rhizobium signaling during establishment of symbiotic nitrogen fixation restricts rhizobium colonization to specific cells. A limited number of root hair cells allow infection threads to form, and only a fraction of the epidermal infection threads progress to cortical layers to establish functional nodules. Here we use single-cell analysis to define the epidermal and cortical cell populations that respond to and facilitate rhizobium infection. We then identify high-confidence nodulation gene candidates based on their specific expression in these populations, pinpointing genes stably associated with infection across genotypes and time points. We show that one of these, which we name SYMRKL1, encodes a protein with an ectodomain predicted to be nearly identical to that of SYMRK and is required for normal infection thread formation. Our work disentangles cellular processes and transcriptional modules that were previously confounded due to lack of cellular resolution, providing a more detailed understanding of symbiotic interactions.

plant biology↗

bioRxiv2022

Resource-aware construct design in mammalian cells

Resource competition can be the cause of unintended coupling between co-expressed genetic constructs. Here we report quantification of the resource load imposed by different mammalian genetic components and identify construct designs with increased performance and reduced resource footprint. We use these to generate improved synthetic circuits and optimise the co-expression of co-transfected cassettes, shedding light on how this can be useful for bioproduction and biotherapeutic applications. This work provides the scientific community with a framework to take resource demand into consideration when designing mammalian constructs to achieve robust and optimised gene expression.

synthetic biology↗

bioRxiv2022

The Translation Initiation Factor Homolog, eif4e1c, Regulates Cardiomyocyte Metabolism and Proliferation During Heart Regeneration

The eIF4E family of translation initiation factors bind 5 methylated caps and act as the limiting-step for mRNA translation. The canonical eIF4E1A is required for cell viability, yet other related eIF4E families exist and are utilized in specific contexts or tissues. Here, we describe a family called Eif4e1c for which we find roles during heart development and regeneration in zebrafish. The Eif4e1c family is present in all aquatic vertebrates but is lost in all terrestrial species. A core group of amino acids shared over 500 million years of evolution forms an interface along the protein surface, suggesting Eif4e1c functions in a novel pathway. Deletion of eif4e1c in zebrafish caused growth deficits and impaired survival in juveniles. Mutants surviving to adulthood had fewer cardiomyocytes and reduced proliferative responses to cardiac injury. Ribosome profiling of mutant hearts demonstrated changes in translation efficiency of mRNA for genes known to regulate cardiomyocyte proliferation. Although eif4e1c is broadly expressed, its disruption had most notable impact on the heart and at juvenile stages. Our findings reveal context-dependent requirements for translation initiation regulators during heart regeneration.

developmental biology↗

bioRxiv2019

Characterization, modelling and mitigation of gene expression burden in mammalian cells

Despite recent advances in genome engineering, the design of genetic circuits in mammalian cells is still painstakingly slow and fraught with inexplicable failures. Here we demonstrate that competition for limited transcriptional and translational resources dynamically couples otherwise independent co-expressed exogenous genes, leading to diminished performance and contributing to the divergence between intended and actual function. We also show that the expression of endogenous genes is likewise impacted when genetic payloads are expressed in the host cells. Guided by a resource-aware mathematical model and our experimental finding that post-transcriptional regulators have a large capacity for resource redistribution, we identify and engineer natural and synthetic miRNA-based incoherent feedforward loop (iFFL) circuits that mitigate gene expression burden. The implementation of these circuits features the novel use of endogenous miRNAs as integral components of the engineered iFFL device, a versatile hybrid design that allows burden mitigation to be achieved across different cell-lines with minimal resource requirements. This study establishes the foundations for context-aware prediction and improvement of in vivo synthetic circuit performance, paving the way towards more rational synthetic construct design in mammalian cells.

synthetic biology↗