Biology subjects

Li, D.

Publications and source records attributed to Li, D..

At least 235 records · Page 13Linked to original sources

bioRxiv2024

Monitoring lysosomal catabolism: a sensitive probe for assessing targeted lysosomal degradation of extracellular proteins

Extracellular targeted protein degradation (eTPD) is an emerging therapeutic field. The Lysosome targeting chimera (LYTAC) is a therapeutic modality that promotes degradation of extracellular drivers of disease in the lysosome. While widely available pH-sensitive probes may report on lysosome delivery, these probes do not necessarily report on the enzymatically active functional state of the lysosome. We report the development and application of a sensitive fluorescent probe, LysoLight Deep Red, to monitor catabolism of internalized proteins in the lysosome based on cleavage by cathepsin proteases. We demonstrate the application of Lysolight Deep Red to monitor the catabolic fate of therapeutic monoclonal antibodies, ASGPR-targeted LYTAC therapeutics and LYTAC targets in immortalized cell lines and in primary human hepatocytes.

cell biology↗

bioRxiv2024

Epigenetic and 3D genome reprogramming during the aging of human hippocampus

Age-related cognitive decline is associated with altered physiology of the hippocampus. While changes in gene expression have been observed in aging brain, the regulatory mechanisms underlying these changes remain underexplored. We generated single-nucleus gene expression, chromatin accessibility, DNA methylation, and 3D genome data from 40 human hippocampal tissues spanning adult lifespan. We observed a striking loss of astrocytes, OPC, and endothelial cells during aging, including astrocytes that play a role in regulating synapses. Microglia undergo a dramatic switch from a homeostatic state to a primed inflammatory state through DNA methylome and 3D genome reprogramming. Aged cells experience erosion of their 3D genome architecture. Our study identifies age-associated changes in cell types/states and gene regulatory features that provide insight into cognitive decline during human aging.

genomics↗

bioRxiv2024

Small-molecule Activation of TFEB Alleviates Niemann-Pick Disease Type C via Promoting Lysosomal Exocytosis and Biogenesis

Niemann-Pick disease type C (NPC) is a devastating lysosomal storage disease characterized by abnormal cholesterol accumulation in lysosomes. Currently, there is no treatment for NPC. Transcription factor EB (TFEB), a member of the microphthalmia transcription factors (MiTF), has emerged as a master regulator of lysosomal function and promoted the clearance of substrates stored in cells. However, it is not known whether TFEB plays a role in cholesterol clearance in NPC disease. Here, we show that transgenic overexpression of TFEB, but not TFE3 (another member of MiTF family) facilitates cholesterol clearance in various NPC1 cell models. Pharmacological activation of TFEB by sulforaphane (SFN), a previously identified natural small-molecule TFEB agonist by us, can dramatically ameliorate cholesterol accumulation in human and mouse NPC1 cell models. In NPC1 cells, SFN induces TFEB nuclear translocation via a ROS-Ca2+-calcineurin dependent but MTOR-independent pathway and upregulates the expression of TFEB-downstream genes, promoting lysosomal exocytosis and biogenesis. While genetic inhibition of TFEB abolishes the cholesterol clearance and exocytosis effect by SFN. In the NPC1 mouse model, SFN dephosphorylates/activates TFEB in brain and exhibits potent efficacy of rescuing the loss of Purkinje cells and body weight. Hence, pharmacological upregulating lysosome machinery via targeting TFEB represents a promising approach to treat NPC and related lysosomal storage diseases, and provides the possibility of TFEB agonists ie SFN as potential NPC therapeutic candidates.

molecular biology↗

bioRxiv2024

PhenoVision: A framework for automating and delivering research-ready plant phenology data from field images

Plant phenology plays a fundamental role in shaping ecosystems, and global change-induced shifts in phenology have cascading impacts on species interactions and ecosystem structure and function. Detailed, high-quality observations of when plants undergo seasonal transitions such as leaf-out, flowering, and fruiting are critical for tracking causes and consequences of phenology shifts, but these data are often sparse and biased globally. These data gaps limit broader generalizations and forecasting improvements in the face of continuing disturbance. One solution to closing such gaps is to document phenology on field images taken by public participants. iNaturalist, in particular, provides global scale research-grade data and is expanding rapidly. Here we utilize over 53 million field images of plants and millions of human annotations from iNaturalist - data spanning all angiosperms and drawn from across the globe - to train a computer vision model (PhenoVision) to detect the presence of fruits and flowers. PhenoVision utilizes a vision transformer architecture pretrained with a masked autoencoder to improve classification success, and it achieves high accuracy for flower (98.5%) and fruit presence (95%). Key to producing research-ready phenology data is post-calibration tuning and validation focused on reducing noise inherent in field photographs, and maximizing the true positive rate. We also develop a standardized set of quality metrics and metadata so that results can be used effectively by the community. Finally, we showcase how this effort vastly increases phenology data coverage, including regions of the globe where data have been limited before. Our end products are tuned models, new data resources, and an application streamlining discovery and use of those data for the broader research and management community. We close by discussing next steps, including automating phenology annotations, adding new phenology targets, e.g., leaf phenology, and further integration with other resources to form a global central database integrating all in-situ plant phenology resources.

ecology↗

bioRxiv2024

Curative levels of endogenous gene replacement achieved in non-human primate liver using programmable genomic integration

The ability to efficiently place a large piece of DNA in a specific genomic location has been a goal for the gene therapy field since its inception; however, despite significant advances in gene editing technology, this had yet to be achieved. Here we describe two methods of programmable genomic integration (PGI) that overcome some of the limitations of current approaches. Using a combination of clinically validated delivery technologies (LNP, AAV), we demonstrate the ability to specifically integrate large (>2 kb) DNA sequences into endogenous introns in the liver of non-human primates (NHP). PGI was effective across multiple genomic locations and transgenes, and insertion led to expression from the endogenous promoter. PGI was highly efficient, achieving expression in >50% of liver cells after a single course of treatment, which would be curative for most monogenic recessive liver diseases. This is the first report of clinically curative level of gene insertion at endogenous loci in NHP.

bioengineering↗

bioRxiv2024

Allele-specific silencing of a dominant SETX mutation in familial amyotrophic lateral sclerosis type 4

Amyotrophic lateral sclerosis 4 (ALS4) is an autosomal dominant motor neuron disease that is molecularly characterized by reduced R-loop levels and caused by pathogenic variants in senataxin (SETX). SETX encodes an RNA/DNA helicase that resolves three-stranded nucleic acid structures called R-loops. Currently, there are no disease-modifying therapies available for ALS4. Given that SETX is haplosufficient, removing the product of the mutated allele presents a potential therapeutic strategy. We designed a series of siRNAs to selectively target the RNA transcript from the ALS4 allele containing the c.1166T>C mutation (p.Leu389Ser). Transfection of HEK293 cells with siRNA and plasmids encoding either wild-type or mutant (Leu389Ser) epitope tagged SETX revealed that three siRNAs specifically reduced mutant SETX protein levels without affecting the wild-type SETX protein. In ALS4 primary fibroblasts, siRNA treatment silenced the endogenous mutant SETX allele, while sparing the wild-type allele, and restored R-loop levels in patient cells. Our findings demonstrate that mutant SETX, differing from wild-type by a single nucleotide, can be effectively and specifically silenced by RNA interference, highlighting the potential of allele-specific siRNA as a therapeutic approach for ALS4.

genetics↗

bioRxiv2024

Regulation of REM Sleep Onset and Homeostasis by Preoptic Glutamatergic Neurons

The preoptic area of the hypothalamus is key for the control of sleep onset and sleep homeostasis. Although traditionally considered exclusively somnogenic, recent studies identified a group of preoptic glutamatergic neurons that promote wakefulness. Specifically, our previous investigations demonstrated that chemogenetic stimulation of glutamatergic neurons within the medial-lateral preoptic area (MLPO_VGLUT2) promotes wakefulness, fragments non-rapid eye movement sleep (NREMs), and suppresses REM sleep (REMs). This evidence is further supported by recent work showing that preoptic glutamatergic neurons are activated during microarousals that fragment sleep in response to stress, and optogenetic stimulation of these neurons promotes microarousals and wakefulness. Thus, while the wake-promoting function of MLPO_VGLUT2 is clear, their role in sleep homeostasis has not been assessed. We tested the hypothesis that MLPO_VGLUT2 are wake-active, and their activation will increase wakefulness and disrupt sleep homeostasis via projections to arousal-promoting systems. Using fiber photometry, we found that MLPO_VGLUT2 were highly active during REMs, wakefulness and brief arousals, and remained minimally active during NREMs. Chemogenetic stimulation of MLPO_VGLUT2 inhibited REMs onset and suppressed the REMs homeostatic response after total sleep deprivation. Chemogenetic inhibition of MLPO_VGLUT2 increased REMs time (during the light phase only) but did not influence REMs and NREMs homeostasis. Anterograde projection mapping revealed that MLPO_VGLUT2 innervate central regions that promote wakefulness and inhibit REMs. We conclude that MLPO_VGLUT2 powerfully suppress REMs and that exogenous --and possibly pathologic-- activation of these neurons disrupts REMs recovery, presumably by directly or indirectly activating REMs-inhibitory mechanisms. SIGNIFICANCE STATEMENTThe preoptic area of the hypothalamus has been extensively studied and its role in sleep regulation is well-established. Importantly, recent work identified a group of preoptic glutamatergic neurons (MLPO_VGLUT2) that are wake-active and promote wakefulness. However, whether these neurons influence sleep homeostasis remains unknown. We demonstrate that MLPO_VGLUT2 are maximally active during REM sleep (REMs), wakefulness and brief arousals from sleep, and innervate wake-promoting and REMs-inhibitory regions. MLPO_VGLUT2 stimulation inhibits REMs and REMs rebound after sleep deprivation, whereas their inactivation increases REMs but does not alter REMs homeostatic response. We thus identified a preoptic mechanism that powerfully suppresses REMs, which we propose may engage during normal sleep-to-wake transitions to block REMs intrusions into subsequent wakefulness.

neuroscience↗

bioRxiv2024

Bottlebrush polymers with sequence-controlled backbones for enhanced oligonucleotide delivery

The clinical translation of oligonucleotide-based thera-peutics continues to encounter challenges in delivery. In this study, we introduce a novel class of delivery vehicles for oligonucleotides, which are based on polyethylene glycol (PEG) bottlebrush polymers with sequence-defined backbones. Using solid-phase synthesis and bespoke phosphoramidites, the oligonucleotide and the polymer backbone can both be assembled on the solid support. The synthesis allows chemical modifiers such as carbon 18 (C18) units to be incorporated into the backbone in specific patterns to modulate the cell-materials interactions. Subsequently, PEG side chains were grafted onto the polymer segment of the resulting polymer-oligonucleotide conjugate, yielding bottlebrush polymers. We report an optimal pattern of the C18 modifier that leads to improved cellular uptake, plasma phar-macokinetics, biodistribution, and antisense activity in vivo. Our results provide valuable insights into the pacDNA structure-property relationship and suggest a possibility of tuning the polymer backbone to meet the specific delivery requirements of various diseases. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=166 SRC="FIGDIR/small/616318v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@1a332e7org.highwire.dtl.DTLVardef@1630ab1org.highwire.dtl.DTLVardef@15306dforg.highwire.dtl.DTLVardef@1e83f0e_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2024

A new stegosaur (Dinosauria: Ornithischia) from the Upper Jurassic Qigu Formation of Xinjiang, China and a revision on Chinese stegosaurs phylogeny

Stegosaurs are a small but iconic clade of ornithischian dinosaurs. They and their sister taxa, the ankylosaurs, formed the clade Eurypoda which means broad-footed. Here, we describe a stegosaur from the Upper Jurassic Qigu Formation of Xinjiang, China, based on an associated partial skeleton that includes axial, pectoral girdle, pelvic girdle, limb and armor elements. It can be diagnosed as a new taxon, Angustungui, based on numerous autapomorphies. Some morphologies of Angustungui are more similar to the taxa from Europe, Africa and North America than to those from Asia. Our phylogenetic analysis recovers it as the sister taxon of Loricatosaurus. More importantly, the narrow and claw-shaped ungual of Angustungui proves that Eurypoda, at least stegosaur, has claw-shaped unguals. Besides, we revised the character scores for Chinese stegosaurs based on observations of the specimens.

paleontology↗

bioRxiv2024

Ligase-mediated programmable genomic integration (L-PGI): an efficient site-specific gene editing system that overcomes the limitations of reverse transcriptase-based editing systems

Since their discovery, CRISPR/Cas9 systems have been repurposed for programmable targeted genomic editing. This has led to unprecedented advancement of gene editing for therapeutic benefit. Initial uses of CRISPR/Cas9 were focused on gene disruption via DNA cleavage, but significant engineering led to systems for single base editing as well as insertion, deletion and manipulation of short stretches of genomic sequences using nicking Cas9 and RT-based methods. These technologies allowed safer and more precise editing but were limited to small corrections and showed significantly reduced efficiencies in nondividing cells, presenting difficulty for translation to in vivo therapies. To find an alternate editing strategy that could address these shortcomings, we revisited the mechanism of DNA nicking by nCas9. nCas9 nicking creates a free 5 phosphate group and a 3 hydroxyl group on the complementary strand of the target sequence. Under ordinary conditions in the cell these ends are re-joined by endogenously expressed ligases to repair DNA back to wild-type. If, however, a DNA fragment containing the desired edit were present, ligation of the nicked genomic DNA with the delivered fragment could result in gene editing. We demonstrate that optimization of each component and introduction of a chemically modified high affinity splinting DNA allows a variety of ligase-based edits, including longer edits not efficient with RT-based systems, at high efficiencies and fidelities that minimize genomic byproducts in both dividing and nondividing cells as well as in vivo in adult mice. Here we present the first therapeutically relevant ligation-based programmable gene editing technology, L-PGI.

bioengineering↗

bioRxiv2024

Preventive Effects of Pomegranate Seed Oil on Transient Middle Cerebral Artery Occlusion via the Keap1/Nrf2/NQO1 Pathway in the rats Cortex

Ischemic stroke remains a pressing challenge that needs to be solved. Energy metabolic failure is a critical factor contributing to mitochondrial dysfunction and oxidative stress in the pathogenesis of brain ischemia, leading to the generation of excessive reactive oxygen species. Pomegranate seed oil (PSO) exhibits antioxidant properties; however, its protective effects against cerebral ischemia/reperfusion injury and the underlying mechanisms remain unclear. In this study, a transient middle cerebral artery occlusion (tMCAO) rat model was employed to simulate cerebral ischemia/reperfusion injury. We investigated the mechanisms by which different concentrations of PSO modulate oxidative damage caused by cerebral ischemia/reperfusion injury through the Keap1/Nrf2/NQO1 pathway in cortex. SD male rats were randomly divided into four groups: Control, tMCAO+NaCl, tMCAO+LO (low concentration of PSO), tMCAO+MO (medium concentration of PSO), and tMCAO+HO (high concentration of PSO). Our findings suggest that low concentration of PSO exerts neuroprotective effects by activating Nrf2 and NQO1, thereby reducing oxidative stress. Furthermore, LO significantly improved neurological scores and reduced neuronal edema. Additionally, the results demonstrated an increase in superoxide dismutase (SOD) levels and a decrease in malondialdehyde (MDA) levels. In contrast, MO and HO exhibited suboptimal effects. To sum up, these results indicate that PSO activates neuroprotective pathways against oxidative stress following cerebral ischemia/reperfusion injury via the Keap1/Nrf2/NQO1 pathway, providing novel insights into potential preventive therapies for cerebral ischemia/reperfusion.

neuroscience↗

bioRxiv2024

Age-related decline of PKA-RIIβ level in SNc dopaminergic neurons underlies PD pathogenesis

The cyclic-AMP dependent protein kinase A (Protein kinase A, PKA) regulates dopaminergic function in the substantia nigra pars compacta (SNc). However, whether PKA is involved in the pathogenesis of Parkinsons disease (PD) is unknown. Here, by collecting and analyzing the current worldwide SNc transcriptomic datasets of PD patients, we found a decline of PKA-RII{beta} subunit level in the SNc of PD patients. The decreased PKA-RII{beta} subunit level was positively correlated with decreased dopamine synthesis and increased oxidative stress in the SNc of PD patients. PKA-RII{beta} subunit is expressed in the striatum and the SNc. PKA-RII{beta} gene knockout mice (RII{beta}-KO) showed a age-related parkinsonism at 12 months of age. Using Cre-LoxP system, we observed that RII{beta} re-expression in the SNc dopaminergic neurons rescued parkinsonism of RII{beta}-KO mice. RII{beta} re-expression in striatal neurons did not affect parkinsonism of RII{beta}-KO mice. The spontaneous parkinsonism could be developed in 12-month-old SNc dopaminergic neuron-specific RII{beta}-deficient mice. Single-nucleus RNA sequencing revealed decreased PKA activity, reduced dopamine synthesis and raised oxidative stress in the SNc dopaminergic neurons of RII{beta}-KO mice. Adeno-associated virus (AAV)-mediated gene therapy targeting PKA-RII{beta} in the SNc dopaminergic neurons rescued parkinsonism in PD mouse model. Taken together, these findings indicate that PKA-RII{beta} may be a key factor of human genetic etiologies of PD. The therapy targeting PKA-RII{beta} in the SNc dopaminergic neurons may be promising for PD treatment.

neuroscience↗

bioRxiv2024

Nutritional analysis of commercially available, complete plant- and meat-based dry dog foods in the UK

BackgroundAdoption of a plant-based diet is a popular lifestyle choice for many owners of canine companion animals. Increasingly, owners would like to feed their canine companions a similar diet. A plant-based dietary pattern has been reported to be associated with some micronutrient deficiencies. Complete dog foods are, by definition, supposed to be nutritionally replete in all macro- and micronutrients. Few studies have reported a full nutritional analysis of complete, dry plant-versus meat-based dog foods. MethodHere, 31 pet foods (n=19 meat-based, n=6 veterinary and n=6 plant-based) were analysed for total protein content and individual amino acids, fatty acids, major and trace elements, vitamin D and all B-vitamins. ResultsNutritional composition of meat and plant-based foods were similar, except for iodine and B-vitamins, which were lower in plant-based foods. The majority (66%) of veterinary diets with lower total protein by design, were also deficient in one or more essential amino acids. Isolated instances of non-compliance to nutritional guidelines were observed across all food-groups. Of the tested nutrients 55%, 16%, 24% and 100% of foods met all amino acid, mineral, B-vitamin, and vitamin D guidelines, respectively. ConclusionsAdopting a plant-based dietary pattern for your companion canine can provide nutritional adequacy with respect to the majority of macro- and micronutrients, but feeding supplemental iodine and B-vitamins should be considered. Veterinary diets, purposely low in crude protein, often have less than optimal essential amino acid composition. These data provide important new information for owners of companion canines being fed plant-based or veterinary diets.

zoology↗

bioRxiv2024

Stress response of membrane-based cell organelles in budding yeast

The organelles of yeast demonstrate diverse morphological traits in response to different stress stimuli. However, there is a lack of systematic reports on the structural changes induced by stress stimuli in all membrane-based organelles. Here, we utilized a set of fluorescent protein-based organelle markers to highlight the distinct characteristics of yeast under various stress triggers, including high temperature, hydrogen peroxide, acetic acid, and ethyl alcohol. We found that all of these organelles undergo alterations in structure or function in response to the four stress triggers we tested. Specifically, filamentous mitochondria rupture into smaller segments when exposed to the above four stress conditions. The structure of the endoplasmic reticulum (ER) remains relatively unchanged, but its function is affected. Additionally, high temperature and hydrogen peroxide can induce the Ire1p-mediated ER unfolded protein response (UPR). The translocation of most nuclear-localized proteins to the cytosol is dependent on the specific stress conditions employed. Under the above stress conditions, the vacuole undergoes fusion, resulting in the formation of a larger vacuole from multiple smaller ones. Meanwhile, acetic acid-induced stress leads to the translocation of vacuole-localized proteins Prc1p and Pep4p to unknown puncta, while Ybh3p relocates from the inner vacuole to the vacuole membrane. Proteins localized in the early Golgi, late Golgi, and late endosomes exhibit distinct traits, such as fading away or mis-localization. The structure and function of peroxisomes, lipid droplets, and autophagosomes also undergo modifications. Furthermore, upon exposure to high temperature and ethanol, apoptosis-related proteins Yca1, Aif1, and Mmi1 aggregate instead of remaining dispersed.

cell biology↗

bioRxiv2024

Identification of leptolin as a novel anti-obesity adipokine

Adipokines are key factors in regulating energy homeostasis. We identified a novel adipokine; we named it Leptolin. In humans, leptolin levels in white adipose tissue were positively corrected with exercise, and negatively associated with body mass index. Leptolin levels were positively correlated with lipolysis-promoting gene expression. Elevated leptolin in plasma of athletes, whereas lowered leptolin in plasma of obese individuals were observed. Leptolin gene-knockout mice exhibited increased adiposity and body weight, and decreased energy expenditure. Leptolin gene-overexpression mice showed obesity-resistant phenotypes. Treatment with leptolin promoted fat mobilization and energy expenditure, and reduced body weight, without affecting food-intake and motor activity. Together, leptolin, a novel adipokine with a capacity to improve metabolic status, may serve as a new therapeutic agent for obesity and metabolic disorders.

physiology↗

bioRxiv2024

Organoid Modeling and Single-Cell Profiling Uncover the Migration Mechanism of Smooth Muscle Cells in Moyamoya Disease

Moyamoya disease (MMD) is a chronic cerebrovascular disorder characterized by progressive occlusion of the intracranial arteries, resulting in severe ischemic or hemorrhagic stroke. The main characteristic of the affected vessels in MMD is arterial intimal thickening. However, there are no in vitro or in vivo models that can mimic its vascular characteristics. Moreover, the mechanisms underlying the intimal thickening remain unexplained. Here, we generated vascular organoids by differentiating human induced pluripotent stem cell derived from the peripheral blood of MMD patients, thereby creating an organoid model reflecting both the genetic background and characteristics of the affected vessels. Through single-cell sequencing, we found the increased vascular smooth muscle cell (VSMC) proportion and its functional abnormalities in MMD organoids. Proteomics and RNA sequencing identified abnormal TUBA4A and TUBB4B overexpression in both the organoids and patient serum. The following in vitro experiments demonstrated that TUBA4A and TUBB4B promote the contractile-to-synthetic phenotypic switching, migration and proliferation in VSMC. Further experiments identified the GJA1-mediated PI3K/AKT/KLF4 pathway as a key regulating pathway of these phenotypic changes in VSMCs. Our findings demonstrate that the abnormal expression of TUBA4A and TUBB4B in VSMC might be a significant contributor to the intimal thickening in the affected vessels of MMD.

cell biology↗

bioRxiv2024

Spatiotemporal Single-Cell Roadmap of Human Skin Wound Healing

Wound healing is vital for human health, yet the details of cellular dynamics and coordination in human wound repair remain largely unexplored. To address this, we conducted single-cell and spatial transcriptomics analyses on human skin and acute wound tissues through inflammation, proliferation, and remodeling phases of wound repair from the same individuals, monitoring the cellular and molecular dynamics of human skin wound healing at an unprecedented spatiotemporal resolution. This singular roadmap reveals the cellular architecture of the wound margin and identifies FOSL1 as a critical driver of re-epithelialization. It shows that pro-inflammatory macrophages and fibroblasts sequentially support keratinocyte migration like a relay race across different healing stages. Comparison with single-cell data from venous and diabetic foot ulcers uncovers a link between failed keratinocyte migration and impaired inflammatory response in chronic wounds. Additionally, comparing human and mouse acute wound transcriptomes underscores the indispensable value of this roadmap in bridging basic research with clinical innovations. HighlightsO_LIA spatiotemporal atlas to explore human in vivo gene expression across wound healing C_LIO_LIWound margin architecture unveils a model for human re-epithelialization C_LIO_LIDistinct healing challenges in venous ulcers and diabetic foot ulcers C_LIO_LIUnique human healing traits emerge in cellular heterogeneity and gene expression C_LI

cell biology↗

bioRxiv2024

MED26-enriched condensates drive erythropoiesis through modulating transcription pausing

The Mediator complex regulates various aspects of hematopoietic development, but whether composition of the Mediator complex undergoes dynamic changes for diversifying transcription and functional outputs is unknown. Here, we found that MED26, a subunit in the core Mediator complex, played a distinctive role in facilitating transcription pausing essential for erythroid development. While most Mediator subunits drastically decreased during this process, MED26 remained relatively abundant. Intriguingly, in the early stages, more than half of MED26 occupancy sites did not co-localize with MED1, a representative Mediator subunit, suggesting these subunits exert context-dependent gene regulation. We revealed that MED26-enriched loci were associated with RNA polymerase pausing. MED26 manifested a markedly preferential recruitment of pausing-related factors, leading to an increase in Pol pausing critical for genome-wide transcription repression during erythropoiesis. Moreover, MED26 exhibited pronounced condensate-forming capability, which was necessary for its function in promoting erythropoiesis and recruiting pausing-related factors. Collectively, this study provides mechanistic insights into the functional coordination of distinct Mediator subunits during development and highlights the switch of transcription condensates towards a MED26 enriched form, which modulates transcription pausing to facilitate transcription repression and erythroid development.

cell biology↗