Biology subjects

Fei, T.

Publications and source records attributed to Fei, T..

27 records · Page 2Linked to original sources

bioRxiv2022

USP10 strikes down Wnt/β-catenin signaling by dual-wielding deubiquitinase activity and phase transition potential

Wnt/{beta}-catenin signaling is a conserved pathway crucially governing development, homeostasis and oncogenesis. Discovery of novel regulators holds great values in both basic and translational research. Through screening, we identified a deubiquitinase (DUB) USP10 as a novel and critical modulator of {beta}-catenin. Mechanistically, USP10 binds to key scaffold Axin1 via conserved motifs and stabilizes Axin1 through K48-linked deubiquitination, and surprisingly, tethers Axin1 and {beta}-catenin physically while promoting phase separation for {beta}-catenin suppression regardless of its enzymatic activity. Functionally, USP10 prominently regulates embryonic development and intestinal homeostasis by antagonizing {beta}-catenin via DUB activity. In colorectal cancer, USP10 substantially represses cancer growth mainly through physical binding compensation and phase separation promotion and correlates with Wnt/{beta}-catenin magnitude clinically. Collectively, we discovered USP10 functioning in multiple biological processes against {beta}-catenin and unearthed a novel enzyme-dependent and -independent "dual-regulating" mechanism by which USP10 utilizes parallelly and context-dependently. USP10 inhibitor was suggested in treating certain Wnt-related diseases.

cell biology↗

bioRxiv2022

Intrinsic RNA targeting constrains the utility of CRISPR-Cas13 systems

CRISPR-Cas13 systems have been adapted as versatile toolkits for RNA-related applications. Here we systematically evaluate the performance of several popular Cas13 family effectors (Cas13a, Cas13b and Cas13d) under lentiviral vectors and reveal surprisingly differential defects and characteristics of these systems. Using RNA immunoprecipitation sequencing, transcriptome profiling, biochemistry analysis, high-throughput CRISPR-Cas13 screening and machine learning approaches, we determine that each Cas13 system has its intrinsic RNA targets in mammalian cells. Viral process-related host genes can be targeted by Cas13 and affect production of fertile lentiviral particles, thereby restricting the utility of lentiviral Cas13 systems. Multiple RNase activities of Cas13 are involved in endogenous RNA targeting. Unlike target-induced nonspecific collateral effect, intrinsic RNA cleavage can be specific, target-independent and dynamically tuned by varied states of Cas13 nucleases. Our work provides guidance on appropriate use of lentiviral Cas13 systems and further raises cautions about intrinsic RNA targeting during Cas13-based basic and therapeutic applications.

molecular biology↗

bioRxiv2022

Global Spatial Transcriptome of Macaque Brain at Single-Cell Resolution

Global profile of gene expression at single-cell resolution remains to be determined for primates. Using a recently developed technology ("Stereo-seq"), we have obtained a comprehensive single-cell spatial transcriptome map at the whole-brain level for cynomolgus monkeys, with [~]600 genes per cell for 10 m-thick coronal sections (up to 15 cm2 in size). Large-scale single-nucleus RNA-seq analysis for [~]1 million cells helped to identify cell types corresponding to Stereo-seq gene expression profiles, providing a 3-D cell type atlas of the monkey brain. Quantitative analysis of Stereo-seq data revealed molecular fingerprints that mark distinct neocortical layers and subregions, as well as domains within subcortical structures including hippocampus, thalamus, striatum, cerebellum, hypothalamus and claustrum. Striking whole-brain topography and coordinated patterns were found in the expression of genes encoding receptors and transporters for neurotransmitters and neuromodulators. These results pave the way for cellular and molecular understanding of organizing principles of the primate brain.

cell biology↗

bioRxiv2021

Modeling CRISPR-Cas13d on-target and off-target effects using machine learning approaches

A major challenge in the application of the CRISPR-Cas13d (RfxCas13d, or CasRx) RNA editing system is to accurately predict its guide RNA (gRNA) dependent on-target and off-target effect. Here, we performed CRISPR-Cas13d proliferation screens that target protein-coding genes and long non-coding RNAs (lncRNAs), followed by a systematic modeling of Cas13d on-target efficiency and off-target viability effect. We first designed a deep learning model, named DeepCas13, to predict the on-target activity of a gRNA with high accuracy from its sequence and secondary structure. DeepCas13 outperforms existing methods and accurately predicts the efficiency of guides targeting both protein-coding and non-coding RNAs (e.g., circRNAs and lncRNAs). Next, we systematically studied guides targeting non-essential genes, and found that the off-target viability effect, defined as the unintended effect of guides on cell viability, is closely related to their on-target RNA cleavage efficiency. This finding suggests that these gRNAs should be used as negative controls in proliferation screens to reduce false positives, possibly coming from the unwanted off-target viability effect of efficient guides. Finally, we applied these models to our screens that included guides targeting 234 lncRNAs, and identified lncRNAs that affect cell viability and proliferation in multiple cell lines. DeepCas13 is freely accessible via http://deepcas13.weililab.org.

bioinformatics↗

bioRxiv2021

A Chemical-Enhanced System for CRISPR-Based Nucleic Acid Detection

The CRISPR-based nucleic acid detection systems such as SHERLOCK, DETECTR and HOLMES have shown great potential for point-of-care testing of viral pathogens, especially in the context of COVID-19 pandemic. Here we optimize several key parameters of reaction chemistry and develop a Chemical Enhanced CRISPR Detection system for nucleic acid (termed CECRID). For the Cas12a/Cas13a-based signal detection phase, we determine buffer conditions and substrate range for optimal detection performance. By comparing several chemical additives, we find that addition of L-proline can secure or enhance Cas12a/Cas13a detection capability. For isothermal amplification phase with typical LAMP and RPA methods, inclusion of L-proline can also enhance specific target amplification as determined by CRISPR detection. Using SARS-CoV-2 pseudovirus, we demonstrate CECRID has enhanced detection sensitivity over chemical additive-null method with either fluorescence or lateral flow strip readout. Thus, CECRID provides an improved detection power and system robustness towards practical application of CRISPR-based diagnostics.

molecular biology↗

bioRxiv2020

A non-canonical EZH2 function sensitizes solid tumors to genotoxic stress

Drugs that block the activity of the methyltransferase EZH2 are in clinical development for the treatment of non-Hodgkin lymphomas harboring gain-of-function EZH2 mutations that enhance its polycomb repressive function. In contrast, in castration-resistant prostate cancer (CRPC) we have previously reported that EZH2 plays a non-canonical role as a transcriptional activator. In this setting, we now show that EZH2 inhibitors can also block the non-canonical activity of EZH2 and inhibit the growth of CRPC cells. Gene expression and epigenomic profiling of cells treated with EZH2 inhibitors demonstrated that rather than de-repressing tumor suppressor genes silenced by PRC2, EZH2 inhibitors downregulate a set of DNA repair genes that are directly regulated by EZH2. In addition, genome-wide CRISPR/Cas9-mediated loss-of-function screens in the presence of EZH2 inhibitors identified these DNA repair genes to underlie the growth-inhibitory function of these compounds. Interrogation of public data from diverse solid tumor types expressing wild-type EZH2 showed that expression of DNA damage repair genes is significantly correlated with cellular sensitivity to EZH2 inhibitors. Consistent with these findings, treatment of CRPC cells with EZH2 inhibitors dramatically enhanced their sensitivity to genotoxic stress. These studies reveal a previously unappreciated mechanism of action of EZH2 inhibitors and provide a mechanistic basis for potential new combination cancer therapies.

cancer biology↗

bioRxiv2020

A single-cell analysis of the molecular lineage of chordate embryogenesis

In multicellular organisms, a single zygote develops along divergent lineages to produce distinct cell types. What governs these processes is central to the understanding of cell fate specification and stem cell engineering. Here we used the protochordate model Ciona savignyi to determine gene expression profiles of every cell of single embryos from fertilization through the onset of gastrulation and provided a comprehensive map of chordate early embryonic lineage specification. We identified 47 cell types across 8 developmental stages up to the 110-cell stage in wild type embryos and 8 fate transformations at the 64-cell stage upon FGF-MAPK inhibition. The identities of all cell types were evidenced by in situ expression pattern of marker genes and expected number of cells based on the invariant lineage. We found that, for the majority of asymmetrical cell divisions, the bipotent mother cell shows predominantly the gene signature of one of the daughter fates, with the other daughter being induced by subsequent signaling. Our data further indicated that the asymmetric segregation of mitochondria in some of these divisions does not depend on the concurrent fate inducing FGF-MAPK signaling. In the notochord, which is an evolutionary novelty of chordates, the convergence of cell fate from two disparate lineages revealed modular structure in the gene regulatory network beyond the known master regulator T/Brachyury. Comparison to single cell transcriptomes of the early mouse embryo showed a clear match of cell types at the tissue level and supported the hypothesis of developmental-genetic toolkit. This study provides a high-resolution single cell dataset to understand chordate embryogenesis and the relationship between fate trajectories and the cell lineage. HighlightsO_LITranscriptome profiles of 47 cell types across 8 stages in early chordate embryo C_LIO_LIBipotent mother in asymmetric division shows the default daughter fate C_LIO_LIModular structure of the notochord GRN beyond the known function of T C_LIO_LIInvariant lineage and manual cell isolation provide truth to trajectory analysis C_LI

developmental biology↗

bioRxiv2019

Batch Effect Correction of RNA-seq Data through Sample Distance Matrix Adjustment

Batch effect is a frequent challenge in deep sequencing data analysis that can lead to misleading conclusions. We present scBatch, a numerical algorithm that conducts batch effect correction on the count matrix of RNA sequencing (RNA-seq) data. Different from traditional methods, scBatch starts with establishing an ideal correction of the sample distance matrix that effectively reflect the underlying biological subgroups, without considering the actual correction of the raw count matrix itself. It then seeks an optimal linear transformation of the count matrix to approximate the established sample pattern. The benefit of such an approach is the final result is not restricted by assumptions on the mechanism of the batch effect. As a result, the method yields good clustering and gene differential expression (DE) results. We compared the new method, scBatch, with leading batch effect removal methods ComBat and mnnCorrect on simulated data, real bulk RNA-seq data, and real single-cell RNA-seq data. The comparisons demonstrated that scBatch achieved better sample clustering and DE gene detection results.

bioinformatics↗

bioRxiv2018

Reducing False Positives in CRISPR/Cas9 Screens from Copy Number Variations

CRISPR/Cas9 knockout screens have been widely used to interrogate gene functions across a wide range of cell systems. However, the screening outcome is biased in amplified genomic regions, due to the ability of the Cas9 nuclease to induce multiple double-stranded breaks and strong DNA damage responses at these regions. We developed algorithms to correct biases associated with copy number variations (CNV), even when the CNV profiles are unknown. We demonstrated that our methods effectively reduced false positives in amplified regions while preserving signals of true positives. In addition, we developed a sliding window approach to estimate regions of high copy numbers for cases in which CNV information is not available. These copy number estimations can subsequently be used to effectively correct CNV-related biases in CRISPR screening experiments. Our approach is integrated into the existing MAGeCK/MAGeCK-VISPR analysis pipelines and provides a convenient framework to improve the precision of CRISPR screening results.

bioinformatics↗