Biology subjects

Chen, C.

Publications and source records attributed to Chen, C..

At least 343 records · Page 19Linked to original sources

bioRxiv2024

Deciphering the molecular mechanism of DNA-protein interactive co-condensates

Nucleic acid and protein co-condensates exhibit diverse morphologies crucial for fundamental cellular processes. Despite their significance, the molecular mechanisms governing morphology transitions remain poorly understood. To address this gap in knowledge, we investigated DNA and the human transcription factor p53 as a model system, specifically focusing on DNA-protein interactive co-condensates (DPICs)--a scenario where neither dsDNA nor the protein demonstrates phase-separation behavior individually. Through a combination of experimental assays and theoretical approaches, we elucidated: (i) the phase diagram of DPICs, identifying two distinct transition phenomena--a phase transition between viscoelastic fluid and viscoelastic solid states, and a morphology transition from droplet-like to "pearl chain"-like DPICs; (ii) the growth dynamics of DPICs. Droplet-like and "pearl chain"-like DPICs, although with dramatically distinct final morphologies and material properties, share a common initial critical microscopic cluster (CMC) size at the nanometer scale during the early stage of phase separation. These findings provide novel insights into the biophysical mechanisms underlying multi-component phase separations within cellular environments. Significance StatementNucleic acids and proteins have the capacity to form co-condensates, exhibiting various morphologies, including droplet-like and "pearl chains" formations. Despite this observation, the underlying biophysical mechanisms remain poorly understood. In this study, we employed DNA and the protein p53 as a model system. Our investigation revealed that the strength of the DNA-p53 interactions dictates the material properties of the co-condensates, leading to a transition from a viscoelastic fluid to a viscoelastic solid phase. This transition is accompanied by a morphological shift from droplet-like formations to structures resembling "pearl chains". Additionally, we explored the growth dynamics of these co-condensates and demonstrated that the strength of p53-DNA interactions influences the relaxation time of the co-condensates, thereby potentially determining their morphological features.

biophysics↗

bioRxiv2024

Optimizing Accuracy and Efficiency in Analyzing Non-UMI Liquid Biopsy Datasets Using the Sentieon ctDNA Pipeline

Sequencing clinical liquid biopsy, especially circulating tumor DNA (ctDNA), provides a valuable method for identifying low allele frequency tumor variants, opening novel clinical applications, particularly in treatment selection for late-stage cancer patients. Despite advancements, challenges in assay development persist, primarily due to limited sample volumes and insufficiency of reads supporting low allele frequency variants. The allele frequencies of clinically significant variants often hover close to the threshold of errors introduced by PCR and sequencing processes. Therefore, more sophisticated analysis methods are crucial to further reduce base error rates, enabling accurate discrimination between background errors and genuine somatic variants. While several ctDNA analysis pipelines have been published and adopted, there is room for improvement in terms of accuracy and run efficiency. In this study, we introduce Sentieons innovative consensus-based ctDNA pipeline - a rapid and precise solution for calling small somatic variants from non-UMI ctDNA sequencing data. The pipeline comprises four core modules: alignment, consensus generation, variant calling, and variant filtering. Through benchmarking with in-vitro and real clinical datasets, we observed that the Sentieon ctDNA pipeline exhibits higher accuracy compared to alternative methods.

bioinformatics↗

bioRxiv2024

Cross-species genomic survey reveals a single origin of the soft-shelled turtles

Turtles have a have a complicated sex determination system; however, Trionychidae species, as a unique group, have evolved a conserved genetic sex determination, which provides an excellent case to study the evolution of environmental sex determination to genetic sex determination. Analysis of the chromosome-level genome assembly, construction of the first sex chromosomes of Trionychidae, and embryonic transcriptome revealed that P. sinensis has a ZW-type sex determination system, and that the key sex-determining genes, including Dmrt1, Amh, Foxl2, etc., and their homologs, are not located on the sex chromosomes, which rejects the involvement of Dmrt1s SDGs or dosage compensation effect in the sex determination of P. sinensis ZW system and also indicates that the ZW chromosomes in birds, turtles, frogs, and fishes originated from different chromosome pairs in the common ancestors. Subsequently, comparative genomic studies demonstrated that a conserved ZW-type sex determination system exists in Trionychidae species, and inferred that their sex chromosomes originate from the same chromosome pair of the common ancestor. More importantly, we found a single origin of the sex chromosomes in Trionychidae species, approximately 56 million years ago, which is highly coincident with the Paleocene-Eocene thermal maximum, PETM, event. Therefore, we hypothesize that the PETM event and the loss of embryonic self-thermal regulation are two critical dynamics that drive the adaptive evolution of sex chromosomes for the common ancestor of Trionychidae species in response to extreme temperature changes. Finally, we link the ancestral sex chromosome origin time, the species divergence time, the PETM event, and the continental plate movements to paint a picture of a single origin and radiation route for extant Trionychidae species. Collectively, our findings provide novel insights into the mechanisms of sex determination in P. sinensis, and the single origin of sex chromosomes and species in extant soft-shelled turtles.

evolutionary biology↗

bioRxiv2024

Overloading And unpacKing (OAK) - droplet-based combinatorial indexing for ultra-high throughput single-cell multiomic profiling

Multiomic profiling of single cells by sequencing is a powerful technique for investigating cellular diversity in complex biological systems. Although the existing droplet-based microfluidic methods have advanced single-cell sequencing, they produce a plethora of cell-free droplets and underutilize barcoding capacities due to their low cell concentration prerequisites. Meanwhile, combinatorial indexing on microplates can index cells in a more effective way; however, it requires time-consuming and laborious protocols involving multiple splitting and pooling steps. Addressing these constraints, we have developed "Overloading And unpacKing" (OAK). With reduced labor intensity, OAK can provide cost-effective multiomic profiling for hundreds of thousands of cells, offering detection sensitivity on par with commercial droplet-based methods. To demonstrate OAKs versatility, we conducted single-cell RNA sequencing (scRNA-Seq) as well as joint single-nucleus RNA sequencing (snRNA-Seq) and single-nucleus Assay for Transposase Accessible Chromatin with sequencing (snATAC-Seq) using cell lines. We further showcased OAKs performance on more complex samples, including in vitro differentiated bronchial epithelial cells and primary retinal tissues. Finally, we examined transcriptomic responses of 408,000 melanoma cells across around 1,000 starting lineages over a 90-day treatment with a RAF inhibitor, belvarafenib. We discovered a rare cell population (0.12%) that underwent a sequence of transcriptomic changes, resulting in belvarafenib resistance. Ultra-high throughput, broad compatibility with diverse molecular modalities, high detection sensitivity, and simplified experimental procedures distinguish OAK from previous methods, and render OAK a powerful tool for large-scale analysis of molecular signatures, even for rare cells.

molecular biology↗

bioRxiv2024

Human induced pluripotent stem cell-derived cardiomyocytes to study inflammation-induced diastolic dysfunction

Heart failure with preserved ejection fraction (HFpEF) is commonly found in persons living with HIV (PLWH) even when antiretroviral therapy (ART) suppresses HIV viremia. However, studying this condition has been challenging because an appropriate animal model is not available. In this paper, we studied calcium transient in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) in culture to simulate the cardiomyocyte relaxation defect noted in of PLWH and HFpEF and to assess whether various drugs have an effect. We show that treatment of hiPSC-CMs with inflammatory cytokines (such as interferon-{gamma} or TNF-) impair their Ca2+ uptake into sarcoplasmic reticulum and that SGLT2 inhibitors, clinically proven as effective for HFpEF, reverse this effect. Additionally, treatment with mitochondrial antioxidants (like mito-Tempo) and certain antiretrovirals resulted in the reversal of the effects of these cytokines on calcium transient. Finally, incubation of hiPSC-CMs with serum from HIV patients with and without diastolic dysfunction did not alter their Ca2+-decay time, indicating that the exposure to the serum of these patients is not sufficient to induce the decrease in Ca2+ uptake in vitro. Together, our results indicate that hiPSC-CMs can be used as a model to study molecular mechanisms of inflammation-mediated abnormal cardiomyocyte relaxation and screen for potential new interventions.

molecular biology↗

bioRxiv2024

DeepResBat: deep residual batch harmonization accounting for covariate distribution differences

Pooling MRI data from multiple datasets requires harmonization to reduce undesired inter-site variabilities, while preserving effects of biological variables (or covariates). The popular harmonization approach ComBat uses a mixed effect regression framework that explicitly accounts for covariate distribution differences across datasets. There is also significant interest in developing harmonization approaches based on deep neural networks (DNNs), such as conditional variational autoencoder (cVAE). However, current DNN approaches do not explicitly account for covariate distribution differences across datasets. Here, we provide mathematical results, suggesting that not accounting for covariates can lead to suboptimal harmonization. We propose two DNN-based covariate-aware harmonization approaches: covariate VAE (coVAE) and DeepResBat. The coVAE approach is a natural extension of cVAE by concatenating covariates and site information with site- and covariate-invariant latent representations. DeepResBat adopts a residual framework inspired by ComBat. DeepResBat first removes the effects of covariates with nonlinear regression trees, followed by eliminating site differences with cVAE. Finally, covariate effects are added back to the harmonized residuals. Using three datasets from three continents with a total of 2787 participants and 10085 anatomical T1 scans, we find that DeepResBat and coVAE outperformed ComBat, CovBat and cVAE in terms of removing dataset differences, while enhancing biological effects of interest. However, coVAE hallucinates spurious associations between anatomical MRI and covariates even when no association exists. Future studies proposing DNN-based harmonization approaches should be aware of this false positive pitfall. Overall, our results suggest that DeepResBat is an effective deep learning alternative to ComBat. Code for DeepResBat can be found here: https://github.com/ThomasYeoLab/CBIG/tree/master/stable_projects/harmonization/An2024_DeepResBat.

neuroscience↗

bioRxiv2024

Role of histone variants H2BC1 and H2AZ.2 in H2AK119ub nucleosome organization and Polycomb gene silencing

Ubiquitination of histone H2A at lysine 119 residue (H2AK119ub) plays critical roles in a wide range of physiological processes, including Polycomb gene silencing 1,2, replication 3-5, DNA damage repair 6-10, X inactivation 11,12, and heterochromatin organization 13,14. However, the underlying mechanism and structural basis of H2AK119ub remains largely elusive. In this study, we report that H2AK119ub nucleosomes have a unique composition, containing histone variants H2BC1 and H2AZ.2, and importantly, this composition is required for H2AK119ub and Polycomb gene silencing. Using the UAB domain of RSF1, we purified H2AK119ub nucleosomes to a sufficient amount and purity. Mass spectrometry analyses revealed that H2AK119ub nucleosomes contain the histone variants H2BC1 and H2AZ.2. A cryo-EM study resolved the structure of native H2AK119ub nucleosomes to a 2.6A resolution, confirming H2BC1 in one subgroup of H2AK119ub nucleosomes. Tandem GST-UAB pulldown, Flag-H2AZ.2, and HA-H2BC1 immunoprecipitation revealed that H2AK119ub nucleosomes could be separated into distinct subgroups, suggesting their composition heterogeneity and potential dynamic organization. Knockout or knockdown of H2BC1 or H2AZ.2 reduced cellular H2AK119ub levels, establishing H2BC1 and H2AZ.2 as critical determinants of H2AK119ub. Furthermore, genomic binding profiles of H2BC1 and H2AZ.2 overlapped significantly with H2AK119ub binding, with the most significant overlapping in the gene body and intergenic regions. Finally, assays in developing embryos reveal an interaction of H2AZ.2, H2BC1, and RING1A in vivo. Thus, this study revealed, for the first time, that the H2AK119ub nucleosome has a unique composition, and this composition is required for H2AK119ub and Polycomb gene silencing.

molecular biology↗

bioRxiv2024

Circatidal control of gene expression in the deep-sea hot vent shrimp Shinkaicaris leurokolos

Biological clocks are a ubiquitous feature of all life, enabling the use of natural environmental cycles to track time. Although studies on circadian rhythms have contributed greatly to the knowledge of chronobiology, biological rhythms in dark biospheres such as the deep sea remain poorly understood. Here, based on a laboratory free-running experiment, we reveal potentially endogenous rhythms in gene expression of the deep-sea hydrothermal vent shrimp Rimicaris leurokolos. Oscillations with [~]12-hour periods, likely reflecting tidal influence, greatly prevail over others in the temporal transcriptome, indicating R. leurokolos likely depends on a circatidal clock consisting of at least some components independent of the circadian clocks. The tidal transcripts exhibit an antiphased expression pattern divided into two internally synchronized clusters, correlated with wide-ranging biological processes that occur in the nucleus and cytoplasm, respectively. In addition, comparing the tidal transcripts with the [~]12-hour ultradian rhythms genes in fruit flies and mice shows large similarity, indicating the likely scenario of broad impact of the tide on the [~]12-hour oscillations across the metazoan. These findings not only provide new insights into the temporal adaptations in deep-sea organisms but also highlight deep-sea hydrothermal vent organisms as intriguing models for chronobiological, particularly 12-hour ultradian rhythms, studies.

ecology↗

bioRxiv2024

Glioma-Induced Alterations in Excitatory Neurons are Reversed by mTOR Inhibition

Gliomas are highly aggressive brain tumors characterized by poor prognosis and composed of diffusely infiltrating tumor cells that intermingle with non-neoplastic cells in the tumor microenvironment, including neurons. Neurons are increasingly appreciated as important reactive components of the glioma microenvironment, due to their role in causing hallmark glioma symptoms, such as cognitive deficits and seizures, as well as their potential ability to drive glioma progression. Separately, mTOR signaling has been shown to have pleiotropic effects in the brain tumor microenvironment, including regulation of neuronal hyperexcitability. However, the local cellular-level effects of mTOR inhibition on glioma-induced neuronal alterations are not well understood. Here we employed neuron-specific profiling of ribosome-bound mRNA via RiboTag, morphometric analysis of dendritic spines, and in vivo calcium imaging, along with pharmacological mTOR inhibition to investigate the impact of glioma burden and mTOR inhibition on these neuronal alterations. The RiboTag analysis of tumor-associated excitatory neurons showed a downregulation of transcripts encoding excitatory and inhibitory postsynaptic proteins and dendritic spine development, and an upregulation of transcripts encoding cytoskeletal proteins involved in dendritic spine turnover. Light and electron microscopy of tumor-associated excitatory neurons demonstrated marked decreases in dendritic spine density. In vivo two-photon calcium imaging in tumor-associated excitatory neurons revealed progressive alterations in neuronal activity, both at the population and single-neuron level, throughout tumor growth. This in vivo calcium imaging also revealed altered stimulus-evoked somatic calcium events, with changes in event rate, size, and temporal alignment to stimulus, which was most pronounced in neurons with high-tumor burden. A single acute dose of AZD8055, a combined mTORC1/2 inhibitor, reversed the glioma-induced alterations on the excitatory neurons, including the alterations in ribosome-bound transcripts, dendritic spine density, and stimulus evoked responses seen by calcium imaging. These results point to mTOR-driven pathological plasticity in neurons at the infiltrative margin of glioma - manifested by alterations in ribosome-bound mRNA, dendritic spine density, and stimulus-evoked neuronal activity. Collectively, our work identifies the pathological changes that tumor-associated excitatory neurons experience as both hyperlocal and reversible under the influence of mTOR inhibition, providing a foundation for developing therapies targeting neuronal signaling in glioma.

neuroscience↗

bioRxiv2024

A conserved Pol II elongator SPT6L mediates Pol V transcription elongation to regulate RNA-directed DNA methylation in Arabidopsis

In plants, the plant-specific RNA polymerase V (Pol V) transcripts non-coding RNAs and provides a docking platform for the association of accessory proteins in the RNA-directed DNA methylation (RdDM) pathway. Various components have been uncovered that are involved in the process of DNA methylation, but it is still not clear how the transcription of Pol V is regulated. Here, we found that the conserved Pol II elongator, SPT6L, bound to thousands of intergenic regions in an RNA polymerase II (Pol II) independent manner. The intergenic enrichment of SPT6L, interestingly, co-occupied with the largest subunit of Pol V (NRPE1) and mutation of SPT6L led to the reduction of DNA methylation but not Pol V enrichment. Furthermore, the association of SPT6L at Pol V loci was dependent on the Pol V associated factor, SPT5L, rather than the presence of Pol V, and the interaction between SPT6L and NRPE1 was compromised in spt5l. Finally, Pol V RIP-seq revealed that SPT6L is required to maintain the amount and length of Pol V transcripts. Our findings thus uncovered the critical role of a Pol II conserved elongator in Pol V mediated DNA methylation and transcription, and shed light on the mutual regulation between Pol V and II in plants.

plant biology↗

bioRxiv2024

The J-Like Protein ARC6 Regulates Chloroplast FtsZ-Ring Assembly through Fine-tuning ARC3 Activity in Arabidopsis

Chloroplast division is initiated by the establishment of the stromal FtsZ ring (Z ring). Assembly and positioning of the Z ring are governed by the chloroplast Min system, which inhibits Z-ring formation everywhere but the middle of the chloroplast. ACCUMULATION AND REPLICATION OF CHLOROPLASTS3 (ARC3), the core component of this system, is a direct inhibitor of Z-ring assembly. Regulation of ARC3 activity is vital thus for chloroplast division. Here, we report that ARC6, which localizes on the chloroplast inner envelope membrane, interacts with ARC3 and acts upstream of ARC3 during chloroplast division. We show that the C-terminal MORN domain of ARC3, demonstrated previously to prevent ARC3-FtsZ interaction, binds to the J-like domain (JLD) of ARC6, enabling full-length ARC3 to interact with FtsZ proteins and activating the inhibitory activity of ARC3 on the assembly of FtsZ filaments. Overexpression of a JLD-deleted version of ARC6 causes disruption of Z-ring formation in an ARC3-dependent manner. Finally, we reveal that ARC6 recruits ARC3 to the middle of the chloroplast. Our findings suggest a model whereby ARC6 regulates the assembly and positioning of the Z ring through fine-tuning the inhibitory activity of ARC3 at the chloroplast division site. One Sentence SummaryThe chloroplast membrane protein ARC6 recruits ARC3 to the chloroplast division site and regulates the assembly of the FtsZ ring by fine-tuning ARC3 activity through its J-like domain. The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (https://academic.oup.com/plcell/pages/General-Instructions) is: Cheng Chen (cgchen@sjtu.edu.cn).

plant biology↗

bioRxiv2024

RBM7 deficiency promotes breast cancer metastasis by coordinating MFGE8 splicing switch and NF-kB pathway

Aberrant alternative splicing is well-known to be closely associated with tumorigenesis of various cancers. However, the intricate mechanisms underlying breast cancer metastasis driven by deregulated splicing events remain largely unexplored. Here, we unveiled that RBM7 is decreased in lymph node and distant organ metastases of breast cancer as compared to primary lesions and low expression of RBM7 is correlated with the reduced disease-free survival of breast cancer patients. Breast cancer cells with RBM7 depletion exhibited an increased potential for lung metastasis compared to scramble control cells. The absence of RBM7 stimulated breast cancer cell migration, invasion, and angiogenesis. Mechanistically, RBM7 controlled the splicing switch of MFGE8, favoring the production of the predominant isoform of MFGE8, MFGE8-L. This resulted in the attenuation of STAT1 phosphorylation and alterations in cell adhesion molecules. MFGE8-L exerted an inhibitory effect on the migratory and invasive capability of breast cancer cells, while the truncated isoform MFGE8-S, which lack the second F5/8 type C domain had the opposite effect. In addition, RBM7 negatively regulates the NF-{kappa}B cascade and an NF-{kappa}B inhibitor could obstruct the increase in HUVEC tube formation caused by RBM7 silencing. Clinically, we noticed a positive correlation between RBM7 expression and MFGE8 exon7 inclusion in breast cancer tissues, providing new mechanistic insights for molecular-targeted therapy in combating breast cancer.

cancer biology↗

bioRxiv2023

PNLDC1 catalysis and postnatal germline function are required for piRNA trimming, LINE1 silencing, and spermatogenesis in mice

PIWI-interacting RNAs (piRNAs) play critical and conserved roles in transposon silencing and gene regulation in the animal germline. Two distinct piRNA populations are present during mouse spermatogenesis: pre-pachytene piRNAs in fetal/neonatal testes and pachytene piRNAs in adult testes. PNLDC1 is required for both pre-pachytene piRNA and pachytene piRNA 3 end maturation in multiple species. However, whether PNLDC1 is the bona fide piRNA trimmer and the physiological role of 3 trimming of two distinct piRNA populations in spermatogenesis remain unclear. Here, by inactivating Pnldc1 exonuclease activity in vitro and in mice, we reveal that PNLDC1 trimmer activity is required for both pre-pachytene piRNA and pachytene piRNA 3 end trimming and male fertility. Furthermore, conditional inactivation of Pnldc1 in postnatal germ cells causes LINE1 transposon de-repression and spermatogenic arrest in mice. This indicates that pachytene piRNA trimming, but not pre-pachytene piRNA trimming, is essential for mouse germ cell development and transposon silencing. Our findings highlight the potential of inhibiting germline piRNA trimmer activity as a potential means for male contraception.

developmental biology↗

bioRxiv2023

Quantitative measurement of microbial growth rate with Raman microspectroscopy

Rates of microbial activity and growth are fundamental to understanding environmental geochemistry and ecology. However, measuring the heterogeneity of microbial activity at the single-cell level, especially within complex populations and environmental matrices, remains a forefront challenge. Stable Isotope Probing (SIP) is a standard method for assessing microbial activity and involves measuring the incorporation of an isotopically labeled compound into microbial biomass. Here, we assess the utility of Raman microspectroscopy as a SIP technique, specifically focusing on the measurement of deuterium (2H), a tracer of microbial biomass production. We generate calibrations of microbial biomass 2H values and find that Raman microspectroscopy reliably quantifies 2H incorporation ranging between 0 and 40 at. %. Applying the results of this calibration to a SIP model, we explicitly parameterize the factors controlling microbial growth quantification, demonstrating how Raman-SIP can measure the growth of microorganisms with doubling times ranging from hours to years. Furthermore, we correlatively compare our Raman-derived measurements with those of nanoscale secondary ion mass spectrometry (nanoSIMS) to compare the relative strengths of nanoSIMS- and Raman-based SIP approaches. We find that Raman microspectroscopy is a robust, accessible methodology that can readily differentiate and quantify the growth of individual microbial cells in complex samples. ImportanceGrowth rate, the rate at which organisms grow and reproduce, is a key metric with which to evaluate microbial physiology and contributions to system-level processes. The heterogeneity of microbial growth across space, time, and populations is often difficult to capture with bulk-scale techniques. Single-cell methods hold promise for measuring the heterogeneity of microbial growth rates and responses to changing conditions in situ, without the need for cultivation of microbial isolates. In this study, we evaluated the ability of Raman microspectroscopy, a non-destructive and rapid technique, to measure the assimilation of isotopically labeled water into individual microbial cells and thereby calculate their rates of growth. We explicitly parameterize the factors controlling the quantification of microbial growth rate and compare this technique to standard methods. The framework we report allows researchers to couple single-cell and aggregate rate measurements to functional or system-level properties, a forefront challenge in microbiology.

microbiology↗

bioRxiv2023

Single-cell RNAseq reveals the pro-regenerative role of senescent FAPs in muscle regeneration

Muscle regeneration is associated with transient induction of cellular senescence. However, the role of senescence in muscle regeneration of young mice remains unclear. Using a mouse model deficient in both Cdkn1a and Cdkn2a, we find that a marked reduction in senescent cells correlates with delayed muscle regeneration. Single-cell RNA sequencing reveals a heterogeneous senescence program composing of multiple cell types. Notably, senescent fibro-adipogenic progenitors (FAPs) upregulate Mcl-1 to acquire apoptosis resistance. Moreover, removing senescent FAPs using a Mcl-1 inhibitor S63845 impairs muscle regeneration. Furthermore, we find that senescent FAPs promotes myogenic differentiation in a paracrine manner. Hence, these results highlight the beneficial role of senescent stromal cells in supporting muscle regeneration.

developmental biology↗

bioRxiv2023

ST-GEARS: Advancing 3D Downstream Research through Accurate Spatial Information Recovery

Three-dimensional Spatial Transcriptomics has revolutionized our understanding of tissue regionalization, organogenesis, and development. However, to reconstruct single sections back to their in situ three-dimensional morphology, existing approaches either only adopt gene expression information to guide reconstruction or overlook shape correction against experiment-induced section distortions. This leads to significant discrepancies between reconstruction results and the actual in vivo locations of cells, imposing unreliable spatial profiles to downstream analysis. To address these challenges, we propose ST-GEARS (Spatial Transcriptomics GEospatial profile recovery system through AnchoRS), which solves optimized anchors between in situ closest spots utilizing expression and structural similarity across sections and recovers in vivo spatial information under the guidance of anchors. By employing innovative Distributive Constraints into the Optimization scheme, it retrieves anchors with higher precision compared to existing methods. Taking these anchors as reference points, ST-GEARS first rigidly aligns sections, then introduces and infers Elastic Fields to counteract distortions. ST-GEARS denoises the fields using context information by Gaussian Denoising. Utilizing the denoised fields, it eliminates distortions and eventually recovers original spatial profile through innovative and mathematically proved Bi-sectional Fields Application. Studying ST-GEARS on both bi-sectional registration and complete tissue reconstruction across sectional distances and sequencing platforms, we observed its outstanding performance in spatial information recovery across tissue, cell, and gene levels compared to current approaches. Through this recovery, ST-GEARS provides precise and well-explainable gears between in vivo situations and 3D in vitro analysis, powerfully fueling the potential of biological discoveries.

bioinformatics↗

bioRxiv2023

Hydrothermal vent fauna of the Galapagos Rift: Updated species list with new records

The sighting of giant bivalves and tubeworms at the Rose Garden vent field on the Galapagos Rift in 1977 marked the discovery of hydrothermal vents, a turning point for modern biology. The following decade saw a flurry of taxonomic descriptions of vent endemic species from the first vents. With the finding of high-temperature black smokers on the East Pacific Rise, exploration shifted away from Galapagos. A faunal list of Galapagos vents with 65 species was published in 1991, then updated to 74 species in 2006. Since then, few expeditions returned to the Galapagos Rift. Here, we revisited several Galapagos vents including recently confirmed high-temperature sites and inactive sulfide mounds. From our collecting efforts and observations, as well as revisions from the literature, we update the faunal list to 92 species including 15 new records, restricted to obvious vent associates. Accurate regional faunal lists are important for understanding the biogeography of vent fauna, and our list will also be valuable for setting management strategies.

zoology↗

bioRxiv2023

Connecting single neuron transcriptomes to the projectome in mouse visual cortex

The mammalian brain is composed of diverse neuron types that play different functional roles. Recent single-cell RNA sequencing approaches have led to a whole brain taxonomy of transcriptomically-defined cell types, yet cell type definitions that include multiple cellular properties can offer additional insights into a neurons role in brain circuits. While the Patch-seq method can investigate how transcriptomic properties relate to the local morphological and electrophysiological properties of cell types, linking transcriptomic identities to long-range projections is a major unresolved challenge. To address this, we collected coordinated Patch-seq and whole brain morphology data sets of excitatory neurons in mouse visual cortex. From the Patch-seq data, we defined 16 integrated morphoelectric-transcriptomic (MET)-types; in parallel, we reconstructed the complete morphologies of 300 neurons. We unified the two data sets with a multi-step classifier, to integrate cell type assignments and interrogate cross-modality relationships. We find that transcriptomic variations within and across MET-types correspond with morphological and electrophysiological phenotypes. In addition, this variation, along with the anatomical location of the cell, can be used to predict the projection targets of individual neurons. We also shed new light on infragranular cell types and circuits, including cell-type-specific, interhemispheric projections. With this approach, we establish a comprehensive, integrated taxonomy of excitatory neuron types in mouse visual cortex and create a system for integrated, high-dimensional cell type classification that can be extended to the whole brain and potentially across species.

neuroscience↗