Biology subjects

Goldstein, B.

Publications and source records attributed to Goldstein, B..

At least 19 recordsLinked to original sources

bioRxiv2026

Understanding How Actomyosin Dynamics Drive Apical Constriction by Systematically Tagging and Mapping Actin-Binding Proteins

Apical constriction shapes tissues in fundamental events including gastrulation and neural tube formation. Diverse actin regulators play key roles in shaping cells, but the spatial distribution of most actin regulators in apical constriction is unknown. Here, we describe a systematic approach revealing the endogenous localization of 49 actin regulators in C. elegans gastrulation -- nearly every actin-binding protein (ABP) expressed in the early embryo -- and we use this atlas to test mechanistic hypotheses. We found that many actin regulators localized basolaterally, dependent on the Arp2/3 complex; that linear actin assembly factors enriched apically; and that apically constricting cells had an extra requirement for membrane-cortical linkers present in all cells. These findings answer some key questions about how ABPs function in apical constriction, and they establish a rich resource for investigating actin organization throughout early C. elegans development and a systematic in vivo protein localization reference for the actin cytoskeleton community.

cell biology↗

bioRxiv2026

Automated Parameter Estimation for Camera Trap Density Models Using Computer Vision-Enhanced Distance Sampling

Models for estimating animal density from camera traps require four parameters informing detection: movement speed, daily activity level, staying time (duration animals remain within the detection zone), and effective detection distance. These parameters traditionally come from labor-intensive manual measurements and auxiliary telemetry. Recent advances in computer vision can provide the positions of animals in camera trap images, which have been used for distance sampling. We extend this approach to extract all four parameters from imagery, providing the first AI-derived estimates of movement speed and staying time from automated coordinate tracking. We also introduce a new joint multi-species hierarchical distance function that estimates deployment-specific effective detection distances while borrowing strength across species through partial pooling. Our pipeline integrates MegaDetector for animal detection, the Segment Anything Model for segmentation, and Dense Prediction Transformers for monocular depth estimation. From frame-level coordinates, we reconstruct movement trajectories across burst sequences to estimate speed with size-biased distribution corrections, calculate staying time through bounding box interpolation, and estimate activity levels from detection timestamps. The joint hierarchical distance function decomposes the detection scale parameter into a shared deployment-level effect and species-specific offsets, so species effects represent deviations from the multi-species average, allowing data-rich species to inform detection conditions where rare species have few observations. AI-derived scene depth enters the model as a covariate on detection range, providing a vegetation openness metric from the same pipeline. To address position errors from depth estimation, we apply data quality filters. We processed 122,574 frames from 181 deployments across montane forests in Washington and Montana, generating parameter estimates for 12 species without manual annotation. Automated speed estimates produced day ranges 2.7 to 4.3 times GPS telemetry-derived daily distances, reflecting differences between encounter velocity within detection zones and landscape-scale displacement. Deployment-level variation in detectability exceeded species-level differences 3:1, with scene depth strongly predicting detection range; mean effective detection distances ranged from 4.1 to 7.6 m. Applied to a Random Encounter Model, these parameters yielded a white-tailed deer density estimate of 21.4 animals/km{superscript 2} and the Random Encounter Staying Time model yielded 11.6animals/km{superscript 2} in Montana. This pipeline enables scalable density estimation across large camera trap networks.

ecology↗

bioRxiv2026

Modified meiosis in the tardigrade Hypsibius exemplaris maintains heterozygosity across the genome

In asexual reproduction, meiosis must be bypassed or altered to maintain ploidy from mother to daughter without fertilization. Most of the ways meiosis can be modified to this end are expected to reduce heterozygosity within individuals; however, many asexual species are highly heterozygous. Asexual reproduction is especially common among species of microscopic, desiccation-tolerant animals such as rotifers, nematodes, and tardigrades, but the cellular and genetic mechanisms underlying asexual reproduction have not been definitively documented in any species of tardigrade. Here, we show that the asexual tardigrade Hypsibius exemplaris fails to complete the cell division of meiosis I, followed by a complete meiosis II-like division, and reproduction proceeds without detectable loss of heterozygosity. We used a combined cytological and genomic approach to characterize the mechanism of reproduction and pattern of allele inheritance in this species. Furthermore, we identified heterozygous variants in a subset of transcriptionally active genes consistent with loss of function in one allele, suggesting that maintained heterozygosity in this species allowed divergence between alleles over time. This work establishes the meiotic mechanism and inheritance pattern of reproduction in H. exemplaris, which provides a framework for interpreting genetic variation in this organism as a laboratory model. Additionally, our finding that meiosis is modified in H. exemplaris via a mechanism that maintains heterozygosity across the genome adds to a growing list of asexual animals that have evolved to reproduce clonally despite the expected long-term costs. Article SummaryAsexual animals must alter meiosis, a highly conserved process of two cell divisions normally used to make eggs and sperm. This study represents the first combined cytological and genetic characterization of how meiosis is modified in a tardigrade. The authors found that the model tardigrade Hypsibius exemplaris modifies meiosis by skipping cytokinesis of the first division, followed by a complete second division. They also found that this species preserves heterozygosity across the genome and from generation to generation. Finally, some genes show evidence of divergence between alleles, supporting a broader conclusion that maintaining heterozygosity influences how asexual species evolve.

genetics↗

bioRxiv2025

Olfactory biopsy analysis of Alzheimer's pathobiology across disease stages

Alzheimers Disease (AD) is a neurodegenerative condition affecting millions worldwide. Defining early pathobiological events remains challenging, in part due to inaccessibility of neural tissue. Because olfactory neurons are accessible, and olfactory loss is prevalent in AD, we evaluated olfactory brush biopsies from controls, individuals with cerebrospinal fluid (CSF) biomarker-confirmed AD, and cognitively typical individuals whose positive biomarkers signal a pre-clinical AD stage. We define via single cell RNA-sequencing (n=22 subjects) conserved neuroinflammatory T cell, myeloid, and olfactory neuron changes detectable even in pre-clinical AD subjects. Activated memory T cell states were a hallmark of pre-clinical AD, paralleling CSF T cell phenotypes seen in advanced disease, accompanied by both microglia-like inflammatory programs and olfactory neuron inflammatory injury. Together, our findings establish a novel platform permitting analysis of neural tissue in AD at its earliest stages.

neuroscience↗

bioRxiv2025

RNA binding by ADARs prevents RNA interference from attacking self-produced dsRNA

The ability of an organism to identify self and foreign RNA is central to eliciting an immune response in times of need while avoiding autoimmunity. As viral pathogens typically employ double-stranded RNA (dsRNA), host identification, modulation, and response to dsRNA is key. However, dsRNA is also abundant in host transcriptomes, raising the question of how these molecules can be differentiated. Two host pathways that regulate dsRNA are A-to-I RNA editing by adenosine deaminases (ADARs), and RNA interference (RNAi). Both mechanisms are important for normal organism development and function by regulating gene expression. Herein, we studied the structure and amount of siRNAs at editing sites and the ability of ADARs to prevent exogenous RNAi using the model organism, Caenorhabditis elegans. We found that the number of siRNAs targeting edited genes is significantly upregulated in ADAR mutant animals. We also found that despite an almost complete depletion of primary siRNAs generated from editing sites in wildtype animals, secondary siRNAs are generated from edited transcripts, suggesting ADARs antagonize only the first step of RNAi processing. We show that ADARs interfere with the efficacy of exogenous RNAi in vivo, probably to prevent trans-silencing, and have indications that ADR-2 binding to the dsRNA is needed for the efficient prevention of RNAi. This work sheds light on how the RNA editing process protects self-produced dsRNAs from aberrant recognition by the immune processes in the cell and from by-product degradation. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=152 SRC="FIGDIR/small/672520v2_ufig1.gif" ALT="Figure 1"> View larger version (72K): org.highwire.dtl.DTLVardef@b34f2corg.highwire.dtl.DTLVardef@130c88org.highwire.dtl.DTLVardef@9be2eborg.highwire.dtl.DTLVardef@4ebeec_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2025

Chromosomes remain individualized through interphase in embryos of the tardigrade Hypsibius exemplaris

Tardigrades are microscopic animals that can survive exceptional levels of ionizing radiation or desiccation - DNA-damaging conditions that would kill most animals. Irradiation or radiomimetic drug treatment of the tardigrade Hypsibius exemplaris can induce remarkably high expression levels of DNA repair genes, primarily those in the base excision repair and nonhomologous end joining pathways. How tardigrades can repair widespread DNA damage without producing frequent, large-scale chromosome structural abnormalities, like chromosome translocations and fusions, is unknown. Here, we report the results of examining chromosome and nuclear architecture throughout the cell cycle in early embryos of H. exemplaris. We found that H. exemplaris chromosomes are maintained in an individualized form throughout the cell cycle. We were surprised to also find that each chromosome is housed in a fully or partially separate lamin-lined compartment, instead of all chromosomes being housed in a single, nearly spherical nuclear lamina and envelope. Our results reveal unusual chromosomal and nuclear organization in a tardigrade. We speculate that these unexpected features might limit chromosomal rearrangements during DNA damage repair in extreme conditions. SIGNIFICANCE STATEMENTO_LIWe have investigated unusual chromosome organization in an organism that survives extremely DNA-damaging environments, a tardigrade, through early embryonic cell cycles. C_LIO_LIChromosomes in fixed and stained embryos appeared more condensed through interphase than is typical for animal cells. C_LIO_LIChromosomes remained individualized, in fully or partially separate lamin-lined compartments, through interphase. C_LIO_LIThe results reveal a unique nuclear and chromosomal organization in tardigrades, which we speculate might contribute to limiting chromosomal structure abnormalities under DNA damaging conditions in nature. C_LI

cell biology↗

bioRxiv2024

Cell signaling facilitates apical constriction by basolaterally recruiting Arp2/3 via Rac and WAVE

Apical constriction is a critical cell shape change that bends tissues. How precisely-localized actomyosin regulators drive apical constriction remains poorly understood. C. elegans gastrulation provides a valuable model to address this question. The Arp2/3 complex is essential in C. elegans gastrulation. To understand how Arp2/3 is locally regulated, we imaged embryos with endogenously-tagged Arp2/3 and its nucleation-promoting factors (NPFs). The three NPFs - WAVE, WASP, and WASH - colocalized with Arp2/3 and controlled Arp2/3 localization at distinct subcellular locations. We exploited this finding to study distinct populations of Arp2/3 and found that only WAVE depletion caused penetrant gastrulation defects. WAVE localized basolaterally with Arp2/3 at cell-cell contacts, dependent on CED-10/Rac. Establishing ectopic cell contacts recruited WAVE and Arp2/3, identifying contact as a symmetry-breaking cue for localization of these proteins. These results suggest that cell-cell signaling via Rac activates WAVE and Arp2/3 basolaterally, and that basolateral Arp2/3 is important for apical constriction.

cell biology↗

bioRxiv2024

Expression patterns of FGF and BMP pathway genes in the tardigrade Hypsibius exemplaris

BackgroundA small number of signaling pathways regulates development in most animals, yet we do not know where these pathways are deployed in embryos of many animal phyla. Filling such gaps can contribute to understanding how diverse body shapes arise from differential deployment of conserved signaling pathways. Here, we examined where conserved pathways are deployed in tardigrades, a panarthropod phylum with miniaturized, segmented bodies. ResultsWe used in situ mRNA detection in the tardigrade Hypsibius exemplaris to reveal expression patterns of FGF and BMP signaling pathway components during body segmentation and early mesoderm development. Among the patterns examined, we found an FGF ligand and receptor expressed near each other in segmentally iterated regions of ectoderm and endomesoderm, respectively. We also found a BMP ligand and antagonist expressed in dorsoventrally-restricted patterns in the lateral ectoderm. ConclusionsThe detected patterns suggested specific hypotheses for further research: possible FGF signaling between ectoderm and endomesoderm, and possible roles of BMP signaling in dorsal-ventral patterning of lateral ectoderm. We compared our results with published expression patterns for FGF and BMP pathways across panarthropods, to contribute to previous hypotheses for how the development of segments and mesoderm may have evolved in the emergence of this clade of diversly-shaped animals. Bullet PointsO_LIDouble mRNA detection in tardigrades revealed expression patterns of FGF and BMP pathway genes C_LIO_LIfgf8 was detected primarily in ectoderm but absent from internal germ layers, and C_LIO_LIfgfrl1 was detected in all layers and enriched in internal layers C_LIO_LIdpp was detected more dorsally than sog in lateral ectoderm C_LIO_LIfgf8 and dpp gene expression exhibit different segmentally iterated domains in ectoderm C_LIO_LIResults suggest specific hypotheses for roles for FGF signaling and BMP signaling in tardigrade development C_LI

developmental biology↗

bioRxiv2023

Tardigrades dramatically upregulate DNA repair pathway genes in response to ionizing radiation

Tardigrades can survive remarkable doses of ionizing radiation, up to about 1000 times the lethal dose for humans. How they do so is incompletely understood. We found that the tardigrade Hypsibius exemplaris suffers DNA damage upon gamma irradiation, but damage is repaired. We show that tardigrades have a specific and robust response to ionizing radiation: irradiation induces a rapid, dramatic upregulation of many DNA repair genes. By expressing tardigrade genes in bacteria, we validate that increased expression of some repair genes can suffice to increase radiation tolerance. We show that at least one such gene is necessary for tardigrade radiation tolerance. Tardigrades ability to sense ionizing radiation and massively upregulate specific DNA repair pathway genes may represent an evolved solution for maintaining DNA integrity. One-Sentence SummaryTardigrades exposed to ionizing radiation survive DNA damage by massively upregulating DNA repair pathway genes.

molecular biology↗

bioRxiv2023

A bacterial expression cloning screen reveals tardigrade single-stranded DNA-binding proteins as potent desicco-protectants

Tardigrades are known for their ability to survive remarkable extremes, but relatively little is known about the molecular underpinnings that allow for their extraordinary stress tolerance. We devised an expression cloning approach to screen for novel protectants from desiccation-tolerant tardigrades. We expressed cDNA libraries from the tardigrades Hypsibius exemplaris and Ramazzottius varieornatus in E. coli and subjected the bacteria to desiccation. Sequencing the populations of surviving bacteria revealed enrichment of mitochondrial single-stranded DNA-binding proteins (mtSSBs) from both tardigrade species. Expression of mtSSBs in bacteria improved desiccation survival to similar levels as some of the best protectants known to date. The DNA-binding activity of the oligonucleotide/oligosaccharide binding (OB) fold domain of mtSSB was necessary and sufficient to improve desiccation tolerance. By comparing the efficacy of mtSSBs from multiple organisms, we provide evidence that desicco-protection is a conserved feature of mtSSBs. More broadly, any OB-fold containing protein may act similarly to promote desiccation tolerance, likely by coating ssDNA to limit damage during desiccation. These results identify single-stranded DNA-binding activity as a potent contributor to extreme desiccation tolerance.

molecular biology↗

bioRxiv2023

Long-distance Wnt transport in axons highlights cell type-specific modes of Wnt transport in vivo

Wnt signaling performs critical functions in development, homeostasis, and disease states. Wnt ligands are secreted signaling proteins that often move between cells to activate signaling across a range of distances and concentrations. In different animals and developmental contexts, Wnts utilize distinct mechanisms for intercellular transport including diffusion, cytonemes and exosomes [1]. Mechanisms for intercellular Wnt dispersal remain controversial in part due to technical challenges with visualizing endogenous Wnt proteins in vivo, which has limited our understanding of Wnt transport dynamics. As a result, the cell-biological bases for long-range Wnt dispersal remain unknown in most instances, and the extent to which differences in Wnt transport mechanisms vary by cell type, organism, and/or ligand remain uncertain. To investigate processes underlying long-range Wnt transport in vivo, we utilized C. elegans as an experimentally tractable model where it is possible to tag endogenous Wnts with fluorescent proteins without disrupting signaling [2]. Live imaging of two endogenously tagged Wnt homologs revealed a novel mode for long-distance Wnt movement in axon-like structures that may complement Wnt gradients generated by diffusion and highlighted cell type-specific Wnt transport processes in vivo.

cell biology↗

bioRxiv2023

Architecture of the cortical actomyosin network driving apical constriction in C. elegans

Apical constriction is a cell shape change that drives key morphogenetic events during development, including gastrulation and neural tube formation. The forces driving apical constriction are primarily generated through the contraction of apicolateral and/or medioapical actomyosin networks. In the Drosophila ventral furrow, the medioapical actomyosin network has a sarcomere-like architecture, with radially polarized actin filaments and centrally enriched non-muscle myosin II and myosin activating kinase. To determine if this is a broadly conserved actin architecture driving apical constriction, we examined actomyosin architecture during C. elegans gastrulation, in which two endodermal precursor cells internalize from the surface of the embryo. Quantification of protein localization showed that neither the non-muscle myosin II NMY-2 nor the myosin-activating kinase MRCK-1 is enriched at the center of the apex. Further, visualization of barbed- and pointed-end capping proteins revealed that actin filaments do not exhibit radial polarization at the apex. Taken together with observations made in other organisms, our results demonstrate that diverse actomyosin architectures are used in animal cells to accomplish apical constriction. SummaryThrough live-cell imaging of endogenously-tagged proteins, Zhang, Medwig-Kinney, and Goldstein show that the medioapical actomyosin network driving apical constriction during C. elegans gastrulation is organized diffusely, in contrast to the sarcomere-like architecture previously observed in the Drosophila ventral furrow.

cell biology↗

bioRxiv2023

The Embryonic Origin of Primordial Germ Cells in the Tardigrade Hypsibius exemplaris

Primordial germ cells (PGCs) give rise to gametes - cells necessary for the propagation and fertility of diverse organisms. Current understanding of PGC development is limited to the small number of organisms whose PGCs have been identified and studied. Expanding the field to include little-studied taxa and emerging model organisms is important to understand the full breadth of the evolution of PGC development. In the phylum Tardigrada, no early cell lineages have been identified to date using molecular markers. This includes the PGC lineage. Here, we describe PGC development in the model tardigrade Hypsibius exemplaris. The four earliest-internalizing cells (EICs) exhibit PGC-like behavior and nuclear morphology. The location of the EICs is enriched for mRNAs of conserved PGC markers wiwi1 (water bear piwi 1) and vasa. At early stages, both wiwi1 and vasa mRNAs are detectable uniformly in embryos, which suggests that these mRNAs do not serve as localized determinants for PGC specification. Only later are wiwi1 and vasa enriched in the EICs. Finally, we traced the cells that give rise to the four PGCs. Our results reveal the embryonic origin of the PGCs of H. exemplaris and provide the first molecular characterization of an early cell lineage in the tardigrade phylum. We anticipate that these observations will serve as a basis for characterizing the mechanisms of PGC development in this animal.

developmental biology↗

bioRxiv2022

The C. elegans Anchor Cell Transcriptome: Ribosome Biogenesis Drives Cell Invasion through Basement Membrane

Cell invasion through basement membrane (BM) barriers is important in development, immune function, and cancer progression. As invasion through BM is often stochastic, capturing gene expression profiles of cells actively transmigrating BM in vivo remains elusive. Using the stereotyped timing of C. elegans anchor cell (AC) invasion, we generated an AC transcriptome during BM breaching. Through a focused RNAi screen of transcriptionally enriched genes, we identified new invasion regulators, including TCTP (Translationally Controlled Tumor Protein). We also discovered gene enrichment of ribosomal proteins. AC-specific RNAi, endogenous ribosome labeling, and ribosome biogenesis analysis revealed a burst of ribosome production occurs shortly after AC specification, which drives the translation of proteins mediating BM removal. Ribosomes also strongly localize to the ACs endoplasmic reticulum (ER) and the endomembrane system expands prior to invasion. We show that AC invasion is sensitive to ER stress, indicating a heightened requirement for translation of ER trafficked proteins. These studies reveal key roles for ribosome biogenesis and endomembrane expansion in cell invasion through BM and establish the AC transcriptome as a resource to identify mechanisms underlying BM transmigration.

cell biology↗

bioRxiv2022

Aβ-CT affective touch: Touch pleasantness ratings for gentle stroking and deep pressure exhibit dependence on A-fibers

Gentle stroking of the skin is a common social touch behavior with positive affective consequences. A preference for slow versus fast stroking of hairy skin has been closely linked to the firing of unmyelinated C-tactile (CT) somatosensory afferents. Because the firing of CT afferents strongly correlates with touch pleasantness, the CT pathway has been considered a social-affective sensory pathway. Recently, ablation of the spinothalamic pathway-thought to convey all C-fiber sensations-in patients with cancer pain impaired pain, temperature, and itch, but not ratings of pleasant touch. This suggested integration of A and CT fiber input in the spinal cord, or A-fiber contributions to computations of touch pleasantness in the brain. However, the causal contribution of A-fibers to touch pleasantness- in humans without pain-remains unknown. In the current, single-blinded study we performed two types of peripheral nerve blocks in healthy adults to temporarily eliminate the contribution of A-fibers to touch perception. Our findings show that when A-fiber function is greatly diminished, the perceived intensity and pleasantness of both gentle stroking and deep pressure are nearly abolished. These findings demonstrate that explicit perception of the pleasantness of CT-targeted brushing and pressure both critically depend on A-fibers.

neuroscience↗

bioRxiv2022

SRGP-1/srGAP and AFD-1/Afadin stabilize HMP-1/α-Catenin at rosettes to seal internalization sites following gastrulation in C. elegans

A hallmark of gastrulation is the establishment of germ layers by internalization of cells initially on the exterior. In C. elegans the end of gastrulation is marked by the closure of the ventral cleft, a structure formed as cells internalize during gastrulation, and the subsequent rearrangement of adjacent neuroblasts that remain on the surface. We found that a nonsense allele of srgp-1/srGAP leads to 10-15% cleft closure failure. Deletion of the SRGP-1 C-terminal domain led to a comparable rate of cleft closure failure, whereas deletion of the N-terminal F-BAR region resulted in milder defects. Loss of the SRGP-1 C-terminus or F-BAR domain results in defects in rosette formation and defective clustering of HMP-1/-catenin in surface cells during cleft closure. A mutant form of HMP-1 with an open M domain can suppress cleft closure defects in srgp-1 mutant backgrounds, suggesting that this mutation acts as a gain-of-function allele. Since SRGP-1 binding to HMP-1 is not favored in this case, we sought another HMP-1 interactor that might be recruited when HMP-1 is constitutively open. A good candidate is AFD-1/Afadin, which genetically interacts with cadherin-based adhesion later during embryonic elongation. AFD-1 is prominently expressed at the vertex of neuroblast rosettes in wildtype, and depletion of AFD-1/Afadin increases cleft closure defects in srgp-1 and hmp-1R551/554A backgrounds. We propose that SRGP-1 promotes nascent junction formation in rosettes; as junctions mature and sustain higher levels of tension, the M domain of HMP-1 opens, allowing maturing junctions to transition from recruitment of SRGP-1 to AFD-1. Our work identifies new roles for -catenin interactors during a process crucial to metazoan development.

developmental biology↗

bioRxiv2022

Deconstructing olfactory epithelium developmental pathways in esthesioneuroblastoma

ImportanceEsthesioneuroblastoma (ENB) is a rare tumor arising from the olfactory cleft region of the nasal cavity. Due to the low incidence of this tumor, as well as an absence of established reagents such as cell lines or murine models, understanding the mechanisms driving ENB pathobiology has been challenging. ObjectiveHere, we sought to apply advances from research on the human olfactory epithelial neurogenic niche, along with new biocomputational approaches, to better understand the cellular and molecular factors in low and high grade ENB and how specific transcriptomic markers may predict prognosis. Design, Setting, and ParticipantsThis was a retrospective biocomputational analysis utilizing human ENB and normal olfactory mucosal tissue and clinical outcomes data. The setting was a large academic medical center. Participants were selected based on available datasets, and included ENB patients across all four tumor grades, and patients with normal olfactory mucosa. Main Outcomes and MeasuresOutcomes include deconvolution analysis, differential gene expression analysis, overall survival, and immunohistochemistry. A machine learning model was used to predict cell-type proportion signatures in ENB, and Kaplan-Meier curves with associated log-rank tests were used to estimate differences in overall survival. ResultsWe analyzed a total of 19 ENB samples (9 low grade I/II, 10 high grade III/IV) with available bulk RNA-Sequencing and survival data, along with 10 samples from normal olfactory mucosa (3 bulk RNA-Sequencing, 7 single cell RNA-Sequencing). The bulk RNA-Sequencing deconvolution model identified a significant increase in globose basal cell (GBC) and CD8 T cell identities in high grade tumors (GBC from approximately 0% to 8%, CD8 T cell from 0.7% to 2.2%), and significant decreases in mature neuronal, Bowmans gland, and olfactory ensheathing programs, in high grade tumors (mature neuronal from 3.7% to approximately 0%, Bowmans gland from 18.6% to 10.5%, olfactory ensheathing from 3.4% to 1.1%). Trajectory analysis identified potential regulatory pathways in proliferative ENB cells, including PRC2. Survival analysis guided by gene expression in bulk RNA-Sequencing data identified favorable prognostic markers such as SOX9, S100B, and PLP1 expression. Conclusions and RelevanceOur analyses provide a basis for additional translational research on ENB management, as well as identification of potential new prognostic markers.

cancer biology↗

bioRxiv2022

Tardigrade small heat shock proteins can limit desiccation-induced protein aggregation

Small heat shock proteins (sHSPs) are chaperones known for their response to heat stress. While sHSPs have well-characterized roles in heat tolerance, potential roles for sHSPs in desiccation tolerance have not been as thoroughly explored. We identified nine sHSPs from the genome of the tardigrade Hypsibius exemplaris, each containing a conserved alpha-crystallin domain flanked by disordered regions. Many of these sHSPs are highly expressed and in some cases are upregulated during desiccation. We found that tardigrade sHSPs were sufficient to improve desiccation tolerance when expressed in E. coli. Purification and subsequent analysis of two sHSPs, HSP21 and HSP24.6, revealed that these proteins can form large complexes in vitro, similar to oligomeric assemblies documented for other sHSPs. These proteins limited heat-induced aggregation of the model enzyme citrate synthase. Heterologous expression of HSP24.6 improved bacterial heat shock survival, and the protein significantly reduced heat-induced aggregation of soluble bacterial protein. Thus, HSP24.6 likely chaperones against protein aggregation to promote survival of heat stress. Furthermore, HSP21 and HSP24.6 also limited desiccation-induced aggregation and loss of function of citrate synthase. This suggests a mechanism by which tardigrade sHSPs promote desiccation tolerance: by limiting desiccation-induced protein aggregation, thereby maintaining proteostasis and supporting survival. These results suggest that sHSPs, classical chaperones, provide a mechanism of general stress resistance that can also be deployed to support survival during anhydrobiosis.

biochemistry↗