Biology subjects

Liu, J.-F.

Publications and source records attributed to Liu, J.-F..

9 recordsLinked to original sources

bioRxiv2026

Outer membrane stiffness gates multidrug tolerance

Bactericidal antibiotics initiate killing through class-specific target damage, yet the cellular properties that determine whether antibiotic-induced damage remains reversible or progresses to irreversible death remains unclear. Here, using kanamycin-centered evolution in Escherichia coli, we identified a multidrug-tolerant mutant that exhibits increased survival across aminoglycosides, {beta}-lactams, quinolones and polymyxins without altered minimum inhibitory concentrations. We demonstrate that mechanistically distinct antibiotics converge on outer membrane destabilization, revealing a shared downstream vulnerability during killing. Elevated outer membrane stiffness limits antibiotic-induced envelope destabilization, thereby gating multidrug tolerance. Orthogonal chemical and physical perturbations further established a quantitative relationship between outer membrane stiffness and antibiotic survival across drug classes. Our findings reveal outer membrane stiffness as a previously unrecognized physical basis of multidrug tolerance and suggest that modulating bacterial envelope mechanics may provide new opportunities for antimicrobial intervention.

microbiology↗

bioRxiv2026

A proteostasis clock underlies the timing of bacterial dormancy and antibiotic tolerance

Bacterial dormancy is a major contributor to antibiotic tolerance and persistent infection, yet the lag time before growth resumption is commonly viewed as a passive consequence of cellular recovery and remains difficult to manipulate. Protein aggregation has been linked to bacterial dormancy, but whether aggregates merely reflect cellular damage or directly regulate lag time remains unclear. Here we show that lag time is quantitatively set by cellular proteostasis through control of replication initiation. Microscopy and proteomic analyses revealed delayed aggregate disassembly as a shared proteostasis defect of long-lag bacteria. We identified the replication initiator DnaA in aggregates, whose spatial separation from the nucleoid directly suppresses DNA synthesis. Combined in vitro reconstitution revealed that aggregation-prone proteins drive dose-dependent, synergistic co-aggregation of DnaA, coupling aggregate burden to DnaA sequestration and lag-time extension. Across diverse genetic and physiological models, we observed a universal scaling relationship between lag-time extension and proteostasis decline. Genetic and chemical perturbations of this proteostasis-replication axis bidirectionally modulate lag time, with increasing proteostasis burden prolonging dormancy and restoring proteostasis or DnaA availability accelerating awakening. We therefore propose that proteostasis functions as a tunable timekeeping system for bacterial dormancy by regulating replication initiation, providing a basis for manipulating bacterial dormancy and antibiotic tolerance.

microbiology↗

bioRxiv2024

Pangenome Reveals Gene Content Variations and Structural Variants Contributing to Pig Characteristics

Pigs are among the most essential sources of high-quality protein in human diets. Structural variants (SVs) are a major source of genetic variants associated with diverse traits and evolutionary events. However, the current linear reference genome of pigs limits the presentation of position information for SVs. In this study, we generated a pangenome of pigs and a genome variation map of 599 deep-sequenced genomes across Eurasia. Moreover, a section-wide gene repertoire was constructed, which indicated that core genes were more evolutionarily conserved than variable genes. Subsequently, we identified 546,137 SVs, their enrichment regions, and relationships with genomic features and found significant divergence across Eurasian pigs. More importantly, the pangenome-detected SVs could complement heritability estimates and genome-wide association studies based only on single nucleotide polymorphisms. Among the SVs shaped by selection, we identified an insertion in the promoter region of the TBX19 gene, which may be related to the development, growth, and timidity traits of Asian pigs and may affect the gene expression. Our constructed pig pangenome and the identified SVs provide rich resources for future functional genomic research on pigs.

genomics↗

bioRxiv2021

Genome Assemblies of the Warthog and Kenyan Domestic Pig Provide Insights into Suidae Evolution and Candidate Genes for African Swine Fever Tolerance

As warthog (Phacochoerus africanus) has innate immunity against African swine fever (ASF), it is critical to understand the evolutionary novelty of warthog to explain its specific ASF resistance. Here, we present two completed new genomes of one warthog and one Kenyan domestic pig, as the fundamental genomic references to decode the genetic mechanism on ASF tolerance. Our results indicated, multiple genomic variations, including gene losses, independent contraction and expansion of specific gene families, likely moulded warthogs genome to adapt the environment. Importantly, the analysis of the presence and absence of genomic sequences revealed that, the warthog genome had a DNA sequence absence of the lactate dehydrogenase B (LDHB) gene on chromosome 2 compared to the reference genome. The overexpression and siRNA of LDHB indicated that its inhibition on the replication of ASFV. Combining with large-scale sequencing data of 123 pigs from all over the world, contraction and expansion of TRIM genes families revealed that TRIM family genes in the warthog genome were potentially responsible for its tolerance to ASF. Our results will help further improve the understanding of genetic resistance ASF in pigs.

genetics↗

bioRxiv2021

The first crested duck genome reveals clues to genetic compensation and crest cushion formation

The Chinese crested (CC) duck is a unique indigenous waterfowl breed with a phenotypic crest trait that affects its high survival rate. Therefore, the CC duck is an ideal model to investigate the genetic compensation response to maintain genetic stability. In the present study, we first generated a chromosome-level genome of CC ducks. Comparative genomics revealed genes related to tissue repair, immune function, and tumors were under strong positive selection, which suggested that these adaptive changes might enhance cancer resistance and immune response to maintain the genetic stability of CC ducks. We sub-assembled a Chinese spot-billed duck genome and detected genome-assembled structure variants among three ducks. Functional analysis revealed that a large number of structural variants were related to the immune system, which strongly suggests the occurrence of genetic compensation in the anti-tumor and immune systems to further support the survival of CC ducks. Moreover, we confirmed that the CC duck originated from the mallard ducks. Finally, we revealed the physiological and genetic basis of crest traits and identified a causative mutation in TAS2R40 that leads to crest formation. Overall, the findings of this study provide new insights into the role of genetic compensation in adaptive evolution.

genomics↗

bioRxiv2020

Rapid Epistatic Mixed Model Association Studies by Controlling Multiple Polygenic Effects

SummaryWe have developed a rapid mixed model algorithm for exhaustive genome-wide epistatic association analysis by controlling multiple polygenic effects. Our model can simultaneously handle additive by additive epistasis, dominance by dominance epistasis and additive by dominance epistasis, and account for intrasubject fluctuations due to individuals with repeated records. Furthermore, we suggest a simple but efficient approximate algorithm, which allows examination of all pairwise interactions in a remarkably fast manner of linear with population size. Application to publicly available yeast and human data has showed that our mixed model-based method has similar performance with simple linear model-based Plink on computational efficiency. It took less than 40 hours for the pairwise analysis of 5,000 individuals genotyped with roughly 350,000 SNPs with five threads on Intel Xeon E5 2.6GHz CPU. Availability and implementationSource codes are freely available at https://github.com/chaoning/GMAT.

bioinformatics↗

bioRxiv2019

A key interfacial residue identified with in-cell structure characterization of a Class-A GPCR dimer

G protein coupled receptors (GPCRs) have been shown homo-dimeric. Despite extensive studies, no single residue has been found essential for dimerization. Lacking an efficient method to shift the monomer-dimer equilibrium also makes functional relevance of GPCR dimer elusive. Here, using fluorescence lifetime-based imaging for distance measurements, we characterize the dimeric structure of GPR17, a class A GPCR, in cells. The structure reveals transmembrane helices 5 and 6 the dimer interface, and pinpoints F229 a key residue, mutations of which can render GPR17 monomeric or dimeric. Using the resulting mutants, we show that GPR17 dimer is coupled to both Gi and Gq signaling and is internalized, whereas GPR17 monomer is coupled to Gi signaling only and is not internalized. We further show that residues equivalent to F229 of GPR17 in several other class A GPCRs are also important for dimerization. Our findings thus provide fresh insights into GPCR structure and function.

biochemistry↗

bioRxiv2018

Efficient Multivariate Analysis Algorithms for Longitudinal Genome-wide Association Studies

MotivationCurrent dynamic phenotyping system introduces time as an extra dimension to genome-wide association studies (GWAS), which helps to explore the mechanism of dynamical genetic control for complex longitudinal traits. However, existing methods for longitudinal GWAS either ignore the covariance among observations of different time points or encounter computational efficiency issues.\n\nResultsWe herein developed efficient genome-wide multivariate association algorithms (GMA) for longitudinal data. In contrast to existing univariate linear mixed model analyses, the proposed new method has improved statistic power for association detection and computational speed. In addition, the new method can analyze unbalanced longitudinal data with thousands of individuals and more than ten thousand records within a few hours. The corresponding time for balanced longitudinal data is just a few minutes.\n\nAvailability and ImplementationWe wrote a software package to implement the efficient algorithm named GMA (https://github.com/chaoning/GMA), which is available freely for interested users in relevant fields.

bioinformatics↗

bioRxiv2018

Mining unknown porcine protein isoforms by tissue-based map of proteome enhances the pig genome annotation

A lack of the complete pig proteome has left a gap in our knowledge of the pig genome and has restricted the feasibility of using pigs as a biomedical model. We developed the tissue-based proteome maps using 34 major normal pig tissues. A total of 7,319 unknown protein isoforms were identified and systematically characterized, including 3,703 novel protein isoforms, 669 protein isoforms from 460 genes symbolized beginning with LOC, and 2,947 protein isoforms without clear NCBI annotation in current pig reference genome. These newly identified protein isoforms were functionally annotated through profiling the pig transcriptome with high-throughput RNA sequencing (RNA-seq) of the same pig tissues, further improving the genome annotation of corresponding protein coding genes. Combining the well-annotated genes that having parallel expression pattern and subcellular witness, we predicted the tissue related subcellular components and potential function for these unknown proteins. Finally, we mined 3,656 orthologous genes for 49.95% of unknown protein isoforms across multiple species, referring to 65 KEGG pathways and 25 disease signaling pathways. These findings provided valuable insights and a rich resource for enhancing studies of pig genomics and biology as well as biomedical model application to human medicine.

genomics↗