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Han, R.

Publications and source records attributed to Han, R..

At least 37 records · Page 2Linked to original sources

CLCNet: a contrastive learning and chromosome-aware network for genomic prediction in plants

Genomic selection (GS) leverages genome-wide markers and phenotypes to predict breeding values, with its effectiveness largely dependent on the accuracy of genomic prediction (GP) models. However, GP methods often struggle to capture inter-individual variability and are limited by the curse of dimensionality, where the number of SNPs far exceeds the sample size. To address these challenges, we present CLCNet (Contrastive Learning and Chromosome-aware Network), a novel deep learning framework that integrates contrastive learning and chromosome-aware feature modeling. CLCNet comprises two key components: (i) a contrastive learning module that enhances the models ability to capture fine-grained, genotype-dependent phenotypic differences among individuals, and (ii) a chromosome-aware module that captures structured feature selection at both chromosome and genome levels, thereby distilling the most informative SNPs. We evaluated CLCNet across four crop species, covering ten agronomically important traits, and compared it with a diverse set of classical linear, machine learning, and deep learning models. CLCNet achieved superior prediction performance, with statistically significant improvements in Pearson correlation coefficient (PCC), ranging from 0.34% to 12.19% over baseline, together with reduced mean squared error (MSE). Performance gains were more pronounced for traits with moderate linkage disequilibrium (LD; r2 = 0.21-0.36) and high heritability (h2 > 0.66), such as those in maize, rapeseed, and soybean. For cotton traits characterized by high LD (r2 = 0.74) and lower heritability (h2 < 0.50), CLCNet maintained robust performance without degradation. Overall, these results demonstrate that CLCNet is an effective framework for improving genomic prediction accuracy and holds strong potential for practical applications in plant breeding. Short abstractCLCNet is a novel deep learning framework for genomic prediction that integrates contrastive learning with chromosome-aware feature selection. By jointly modeling inter-individual genotype-phenotype variation and chromosomal genomic structure, CLCNet improves prediction accuracy under high-dimensional, low-sample-size conditions. Across four crop species and ten agronomic traits, CLCNet consistently outperformed classical statistical, machine learning, and existing deep learning models. The framework also identified biologically relevant SNPs and candidate genes, demonstrating its potential for practical applications in genomic selection and computational plant breeding. Key pointsO_LIWe propose CLCNet, a multi-task deep learning framework that integrates contrastive learning with chromosome-aware feature selection for genomic prediction, under high-dimensional, low-sample-size conditions. C_LIO_LIThe chromosome-aware module explicitly exploits genomic structural information to select representative and informative SNPs across chromosomes. C_LIO_LIContrastive learning improves model robustness by stabilizing representation learning and reducing the influence of random effects across samples. C_LIO_LIBy complementing GWAS analyses, CLCNet provides additional insights into genotype-phenotype relationships with potential relevance for gene discovery. C_LI Biographical NoteJiangwei Huang is a PhD candidate at the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences. His research focuses on genomic prediction, deep learning, and computational plant breeding. Zhihan Yang is a PhD candidate at the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences. Her research interests include genomic prediction and bioinformatics. Rongcheng Han is an associate professor at the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences. His research focuses on bioinformatics and plant phenomics. Yuqiang Jiang is a professor at the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences. His research interests include plant genomics, plant phenomics and genetic improvement. Organization descriptionThe Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, is a leading research institute focusing on genetics, genomics, molecular breeding, bioinformatics, and systems biology in plants and animals.

genomics↗

Rag2Mol: Structure-based drug design based on Retrieval Augmented Generation

Artificial intelligence (AI) has brought tremendous progress to drug discovery, yet identifying hit and lead compounds with optimal physicochemical and pharmacological properties remains a significant challenge. Structure-based drug design (SBDD) has emerged as a promising paradigm, but the inherent data biases and ignorance of synthetic accessibility render SBDD models disconnected from practical drug discovery. In this work, we explore two methodologies, Rag2Mol-G and Rag2Mol-R, both based on retrieval-augmented generation (RAG) to design small molecules to fit a 3D pocket. These two methods involve searching for similar small molecules that are purchasable in the database based on the generated ones, or creating new molecules from those in the database that can fit into a 3D pocket. Experimental results demonstrate that Rag2Mol methods consistently produce drug candidates with superior binding affinities and drug-likeness. We find that Rag2Mol-R provides a broader coverage of the chemical landscapes and more precise targeting capability than advanced virtual screening models. Notably, both workflows identified promising inhibitors for the challenging target PTPN2, which was considered undruggable because of structural characteristics of phosphatases. Our highly extensible framework can integrate diverse SBDD methods, marking a significant advancement in AI-driven SBDD. The codes are available at: https://github.com/CQ-zhang-2016/Rag2Mol.

bioinformatics↗

Estrous phase during fear extinction modulates fear relapse through a nigrostriatal dopamine pathway

Elevated ovarian hormones during fear extinction can enhance fear extinction memory retention and reduce renewal, but the mechanisms remain unknown. Ovarian hormones modulate dopamine (DA) transmission, a key player in fear extinction. In males, stimulation of substantia nigra (SN) DA neurons during fear extinction reduces renewal; an effect mimicked by a DA D1 receptor agonist into the dorsolateral striatum (DLS). The current studies tested the role of the SN-DLS pathway in estrous cycle-modulation of fear extinction and relapse. In cycling female, Long-Evans rats, fear extinction during proestrus or estrus (Pro/Est; high hormones) resulted in less relapse (renewal and spontaneous recovery) compared to males or females in metestrus or diestrus (Met/Di; low hormones). This effect was mimicked by estradiol (E2) administration to ovariectomized rats. Females in Pro/Est had greater fear extinction-induced cFos within SN DA neurons compared to males. Similarly, fast scan cyclic voltammetry revealed that electrically-evoked DA release in the DLS is potentiated by E2 and is greater during Pro/Est compared to Met/Di. An inhibitory intersectional chemogenetic approach targeting the SN-DLS pathway suppressed electrically-evoked DA release in the DLS and restored fear renewal in females exposed to simultaneous fear extinction and SN-DLS inhibition during Pro/Est. Conversely, chemogenetic stimulation of the SN-DLS pathway during extinction reduced fear renewal in males. These data suggest that levels of ovarian hormones present during fear extinction modulate relapse through a SN-DLS pathway, and that the SN-DLS pathway represents a novel target for the reduction of fear relapse in both sexes.

neuroscience↗

Pharmacological manipulations of the dorsomedial and dorsolateral striatum during fear extinction have opposing effects on fear renewal

Systemic manipulations that enhance dopamine (DA) transmission around the time of fear extinction can strengthen fear extinction and reduce conditioned fear relapse. Prior studies investigating the brain regions where DA augments fear extinction focus on targets of mesolimbic and mesocortical DA systems originating in the ventral tegmental area, given the role of these DA neurons in prediction error. The dorsal striatum (DS), a primary target of the nigrostriatal DA system originating in the substantia nigra (SN), is implicated in behaviors beyond its canonical role in movement, such as reward and punishment, goal-directed action, and stimulus-response associations, but whether DS DA contributes to fear extinction is unknown. We have observed that chemogenetic stimulation of SN DA neurons during fear extinction prevents the return of fear in contexts different from the extinction context, a form of relapse called renewal. This effect of SN DA stimulation is mimicked by a DA D1 receptor (D1R) agonist injected into the DS, thus implicating DS DA in fear extinction. Different DS subregions subserve unique functions of the DS, but it is unclear where in the DS D1R agonist acts during fear extinction to reduce renewal. Furthermore, although fear extinction increases neural activity in DS subregions, whether neural activity in DS subregions is causally involved in fear extinction is unknown. To explore the role of DS subregions in fear extinction, adult, male Long-Evans rats received microinjections of either the D1R agonist SKF38393 or a cocktail consisting of GABAA/GABAB receptor agonists muscimol/baclofen selectively into either dorsomedial (DMS) or dorsolateral (DLS) DS subregions immediately prior to fear extinction, and extinction retention and renewal were subsequently assessed drug-free. While increasing D1R signaling in the DMS during fear extinction did not impact fear extinction retention or renewal, DMS inactivation reduced later renewal. In contrast, DLS inactivation had no effect on fear extinction retention or renewal but increasing D1R signaling in the DLS during extinction reduced fear renewal. These data suggest that DMS and DLS activity during fear extinction can have opposing effects on later fear renewal, with the DMS promoting renewal and the DLS opposing renewal. Mechanisms through which the DS could influence the contextual gating of fear extinction are discussed. HighlightsO_LIDorsolateral striatum D1 receptor signaling during fear extinction reduces renewal C_LIO_LINeural activity in the dorsomedial striatum during fear extinction permits renewal C_LIO_LIDorsal striatum subregions have opposing roles in contextual gating of fear extinction C_LI Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=51 SRC="FIGDIR/small/576042v2_ufig1.gif" ALT="Figure 1"> View larger version (8K): org.highwire.dtl.DTLVardef@6d935org.highwire.dtl.DTLVardef@19e51acorg.highwire.dtl.DTLVardef@103fa30org.highwire.dtl.DTLVardef@1e7017_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

Harnessing Landrace Diversity Empowers Wheat Breeding for Climate Resilience

Breeding crops resilient to climate change is urgently needed to help ensure food security. A key challenge is to harness genetic diversity to optimise adaptation, yield, stress resilience and nutrition. We examined the genetic and phenotypic diversity of the A.E. Watkins landrace collection of bread wheat (Triticum aestivum), a major global cereal, through whole-genome re-sequencing (827 Watkins landraces and 208 modern cultivars) and in-depth field evaluation spanning a decade. We discovered that modern cultivars are derived from just two of the seven ancestral groups of wheat, leaving five groups as previously untapped sources for breeding. This provides access to landrace-specific functional variations using structured germplasm, genotyping and informatics resources. Employing complementary genetic populations and approaches, we identified thousands of high-resolution quantitative trait loci (QTL) and significant marker-trait associations for major traits, revealing many Watkins-unique loci that can confer superior traits in modern wheat. Furthermore, we identified and functionally verified causative genes for climate-change adaptation, nutritional enhancement and resistance to wheat blast. Finally, we assessed the phenotypic effects of 44,338 Watkins-unique haplotypes, introgressed from 143 prioritised QTL in the context of modern cultivars, bridging the gap between landrace diversity and current breeding. This study establishes a framework for systematically utilising genetic diversity in crop improvement to achieve sustainable food security.

plant biology↗

Time-Informed Dimensionality Reduction for Longitudinal Microbiome Studies

Longitudinal studies are crucial for understanding complex microbiome dynamics and their link to health. We introduce TEMPoral TEnsor Decomposition (TEMPTED), a time-informed dimensionality reduction method for high-dimensional longitudinal data that treats time as a continuous variable, effectively characterizing temporal information and handling varying temporal sampling. TEMPTED captures key microbial dynamics, facilitates beta-diversity analysis, and enhances reproducibility by transferring learned representations to new data. In simulations, it achieves 90% accuracy in phenotype classification, significantly outperforming existing methods. In real data, TEMPTED identifies vaginal microbial markers linked to term and preterm births, demonstrating robust performance across datasets and sequencing platforms.

bioinformatics↗

PGAR-Zernike: an ultra-fast, accurate and fully open-sourcestructure retrieval toolkit for convenient structural database construction

With the release of AlphaFold2, protein model databases are growing at an unprecedented rate. Efficient structure retrieval schemes are becoming more and more important to quickly analyze structure models. The core problem in structural retrieval is how to measure the similarity between structures. Some structure alignment algorithms can solve this problem but at a substantial time cost. At present, the state-of-the-art method is to convert protein structures into 3D Zernike descriptors and evaluate the similarity between structures by Euclidean distance. However, methods for computing 3D Zernike descriptors of protein structures are almost always based on structural surfaces and most are web servers, which is not conducive for users to analyze customized datasets. To overcome this limitation, we propose PGAR-Zernike, a convenient toolkit for computing different types of Zernike descriptors of structures: the user simply needs to enter one line of command to calculate the Zernike descriptors of all structures in a customized datasets. Compared with the state-of-the-art method based on 3D Zernike descriptors and an efficient structural comparison tool, PGAR-Zernike achieves higher retrieval accuracy and binary classification accuracy on benchmark datasets with different attributes. In addition, we show how PGA-Zernike completes the construction of the descriptor database and the protocol used for the PDB dataset so as to facilitate the local deployment of this tool for interested readers. We construct a demonstration containing 590685 structures; at this scale, our retrieval system takes only 4 ~ 9 seconds to complete a retrieval, and experiments show that it reaches the state-of-the-art level in terms of accuracy. PGAR-Zernike is an open-source toolkit, whose source code and related data are accessible at https://github.com/junhaiqi/PGAR-Zernike/.

bioinformatics↗

Targeted cohesin loading characterizes the entry and exit sites of loop extrusion trajectories

The cohesin complex shapes chromosomes by DNA loop extrusion, but individual extrusion trajectories were so far unappreciable in vivo. Here, we developed and validated TArgeted Cohesin Loader (TACL), a system enabling the strong activation of anchored loop extrusion from dozens of defined genomic sites in living cells. Studying their individual loop extrusion trajectories revealed that extruding cohesinSTAG2 stops not only at domain boundaries but at all flanking CTCF sites, engaging them in a complex transient looping network that supports intradomain contacts. CohesinSTAG1 cannot associate with weak CTCF binding sites and fails to similarly support intradomain interactions. NIPBL-MAU2 remains associated with cohesin when stalled at looping CTCF sites, suggesting these factors may also be required for loop stabilization. TACL induces cohesin traffic jams and illegal loops with divergent CTCF sites, demonstrating that stalled cohesin can block extruding cohesin in vivo. Genes exposed to TACL-induced loop extrusion were collectively hindered in transcription and the underlying chromatin altered its accessibility and reduced its H3K27ac marks. Thus, by enabling the study of individual loop extrusion trajectories in vivo, we could assign new functions to players, identify new looping networks and uncover an interplay between loop extrusion, gene transcription and chromatin composition.

genomics↗

Accurate de novo prediction of RNA 3D structure with transformer network

RNA 3D structure prediction remains challenging though after years of efforts. Inspired by the recent breakthrough in protein structure prediction, we developed trRosettaRNA, a novel deep learning-based approach to de novo prediction of RNA 3D structure. Like trRosetta, the trRosettaRNA pipeline comprises two major steps: 1D and 2D geometries prediction by a transformer network; and full-atom 3D structure folding by energy minimization with constraints from the predicted geometries. We benchmarked trRosettaRNA on two independent datasets. The results show that trRosettaRNA outperforms other conventional methods by a large margin. For example, on 25 targets from the RNA-Puzzles experiments, the mean RMSD of the models predicted by trRosettaRNA is 5.5 [A], compared with 10.5 [A] from the state-of-the-art human group (i.e., Das). Further comparisons with two recently released deep learning-based methods (i.e., DeepFoldRNA and RoseTTAFoldNA) show that all three methods have similar accuracy. However, trRosettaRNA yields more accurate and physically more realistic side-chain atoms than DeepFoldRNA and RoseTTAFoldNA. Finally, we apply trRosettaRNA to predict the structures for the Rfam families that do not have known structures. Analysis shows that for 263 families, the predicted structure models are estimated to be accurate with RMSD < 4 [A]. The trRosettaRNA server and the package are available at: https://yanglab.nankai.edu.cn/trRosettaRNA/.

bioinformatics↗

Targeting oncogenic Wnt/β-catenin signaling in adrenocortical carcinoma disrupts ECM expression and impairs tumor growth.

Adrenocortical carcinoma (ACC) is a rare, but highly aggressive cancer with limited treatment options and poor survival for patients with advanced disease. Improved understanding of transcriptional programs engaged in ACC will help direct rational, targeted therapies. While activating mutations in Wnt/{beta}-catenin signaling are frequently observed, the {beta}-catenin-dependent transcriptional targets that promote tumor progression are poorly understood. To address this question, we used independent component analysis and identified a novel Wnt/{beta}-catenin-associated signature in ACC predictive of poor survival. This signature was enriched for the extracellular matrix (ECM), suggesting a potential role for Wnt/{beta}-catenin in regulating the ACC microenvironment. We further investigated the minor fibrillar collagen, collagen XI alpha 1 (COL11A1), and found that COL11A1 expression strongly correlated with both Wnt/{beta}-catenin activation and poor patient survival. Inhibition of constitutively active Wnt/{beta}-catenin signaling in the human ACC cell line, NCI-H295R, significantly reduced expression of COL11A1 and other ECM components, and decreased viability of cancer cells in vitro. To investigate the preclinical potential of Wnt/{beta}-catenin inhibition in vivo, we developed and characterized a novel orthotopic xenograft model utilizing minimally invasive techniques. Treatment with the newly developed Wnt/{beta}-catenin:TBL1 inhibitor Tegavivint significantly reduced tumor growth in this preclinical model. Together, our data supports that inhibition of aberrantly active Wnt/{beta}-catenin disrupts transcriptional reprogramming of the microenvironment and reduces ACC growth and survival. Furthermore, this {beta}-catenin-dependent oncogenic program can be therapeutically targeted with a newly developed Wnt/{beta}-catenin inhibitor. These results show promise for further clinical development of Wnt/{beta}-catenin inhibitors in ACC and unveil a novel Wnt/{beta}-catenin-regulated transcriptome. Simple SummaryAdrenocortical carcinoma (ACC) is a rare, often deadly cancer arising from the adrenal gland. Mortality associated with ACC remains unchanged over the last several decades. The rarity of ACC, an incomplete understanding of its molecular basis, and limited availability of pre-clinical models have hampered the development of new effective therapies. The present work aims to address these gaps with a focus on the Wnt/{beta}-catenin cell signaling pathway, which is aberrantly activated in ~40% of ACC tumors. We discover a novel ECM program activated in ACC that is associated with Wnt/{beta}-catenin and poor survival. Wnt/{beta}-catenin inhibition disrupts expression of ECM genes and induces loss of cancer cell viability. To extend these findings, we develop a rapid orthotopic mouse model of ACC and demonstrate that disruption of the Wnt/{beta}-catenin axis with novel small molecule inhibitor Tegavivint is a potential effective therapeutic strategy to reduce ACC tumor burden in vivo.

cancer biology↗

Genome assembly and association tests identify interacting loci associated with vigor, precocity, and sex in interspecific pistachio rootstocks

Understanding the basis of hybrid vigor remains a key question in crop breeding and improvement, especially for rootstock development where F1 hybrids are extensively utilized. Full-sibling UCB-1 F1 seedling rootstocks are widely planted in commercial pistachio orchards that are generated by crossing two highly heterozygous outbreeding parental trees of Pistacia atlantica (female) and P. integerrima (male). This results in extensive phenotypic variability, prompting costly removal of low-yielding small trees. To identify the genetic basis of this variability, we assembled chromosome-scale genome assemblies of the parental trees of UCB-1. We genotyped 960 UCB-1 trees in an experimental orchard for which we also collected multi-year phenotypes. We genotyped an additional 1,358 rootstocks in six commercial pistachio orchards and collected single-year tree size data. Genome-wide single marker association tests identified loci associated with tree size and shape, sex, and precocity. In the experimental orchard, we identified multiple trait-associated loci and a strong candidate for ZZ/ZW sex chromosomes. We found significant marker associations unique to different traits and to early vs. late phenotypic measures of the same trait. We detected two loci strongly associated with rootstock size in commercial orchards. Pseudo-testcross classification of markers demonstrated that the trait-associated alleles for each locus were segregating in the gametes of opposite parents. These two loci interact epistatically to generate the bimodal distribution of tree size with undesirable small trees observed by growers. We identified candidate genes within these regions. These findings provide a foundational resource for marker development and genetic selection of vigorous pistachio UCB-1 rootstock.

genetics↗

IDOL deficiency inhibits cholesterol-rich diet-induced atherosclerosis in rabbits

BACKGROUNDThe E3 ubiquitin ligase IDOL (Inducible Degrader of the LDL-Receptor) contributes to regulation of cholesterol metabolism through degradation of LDLR, VLDLR and ApoER2. Human genetic studies support the hypothesis that IDOL could serve as a target for the treatment of dyslipidemia. However, species-specific differences in overall lipid metabolism and IDOL regulation require new preclinical models to realize its therapeutic potential. We leveraged the advantages afforded by the rabbit model to address those limitations and generated a novel rabbit IDOL knockout, which we characterized in the context of atherosclerosis. METHODSIDOL-/- rabbits were generated by CRISPR/Cas9 technology. IDOL-/- and wildtype littermates, on standard (SD) and atherogenic high-cholesterol diets (HCDs) were compared through assessment of lipid and lipoprotein profiles, triglyceride clearance, lipoprotein lipase (LPL) activity, liver pathology, atherosclerosis development, and fecal cholesterol, with bile acid contents assessed by mass spectrometry. ResultsHepatic IDOL expression was increased in response to hypercholesterolemia and hypertriglyceridemia induced by HCD. On SD, loss of IDOL increased LDLR stability with reduced total cholesterol in plasma. On HCD, IDOL-/- rabbits showed simultaneous and remarkable reduction in hypercholesterolemia and hypertriglyceridemia associated with enhanced lipid clearance and LPL activity as well as increased bile acid excretion in feces. IDOL-/- rabbits presented markedly reduced HCD-induced atherosclerosis in the aorta and left coronary artery, without enhanced liver steatosis. CONCLUSIONSLoss of IDOL in rabbits recapitulates human genetic findings, thus setting the stage to accelerate preclinical studies towards development of strategies targeting IDOL for the treatment of atherosclerotic cardiovascular disease.

physiology↗

A hybrid unsupervised approach for accurate short read clustering and barcoded sample demultiplexing in nanopore sequencing

Short nucleic acid sequences are usually attached as DNA barcodes for multiple sample sequencing and single cell protocols, which enables Oxford Nanopore sequencing to sequence multiple barcoded DNA samples on a single flow cell. However, due to the high base-calling error, short reads in Nanopore sequencing are difficult to be accurately identified by traditional tools. Here, we propose a hybrid unsupervised approach for the accurate clustering of short reads and demultiplexing of barcoded samples in Nanopore sequencing. In our approach, both the nucleic base information translated from base-calling and the raw current signal directly outputted by the flow cell are utilized. A GPU-supported parallelization strategy is proposed to ensure the runtime of our hybrid clustering. Comprehensive experiments demonstrate that our approach outperforms all the traditional unsupervised tools in short read clustering, and achieves comparable accuracy in barcoded sample demultiplexing compared with the learning-based methods.

bioinformatics↗

Building regulatory landscapes: enhancer recruits cohesin to create contact domains, engage CTCF sites and activate distant genes

Developmental gene expression is often controlled by distal tissue-specific enhancers. Enhancer action is restricted to topological chromatin domains, typically formed by cohesin-mediated loop extrusion between CTCF-associated boundaries. To better understand how individual regulatory DNA elements form topological domains and control expression, we used a bottom-up approach, building active regulatory landscapes of different sizes in inactive chromatin. We demonstrate that transcriptional output and protection against gene silencing reduces with increased enhancer distance, but that enhancer contact frequencies alone do not dictate transcription activity. The enhancer recruits cohesin to stimulate the formation of local chromatin contact domains and activate flanking CTCF sites for engagement in chromatin looping. Small contact domains can support strong and stable expression of distant genes. The enhancer requires transcription factors and mediator to activate genes over all distance ranges, but relies on cohesin exclusively for the activation of distant genes. Our work supports a model that assigns two functions to enhancers: its classic role to stimulate transcription initiation and elongation from target gene promoters and a role to recruit cohesin for the creation of contact domains, the engagement of flanking CTCF sites in chromatin looping, and the activation of distal target genes.

molecular biology↗

Variance of allele balance calculated from low coverage sequencing data infers departure from a diploid state.

MotivationPolyploidy and heterokaryosis are common and consequential genetic phenomena that increase the number of haplotypes in an organism and complicate whole-genome sequence analysis. Allele balance has been used to infer polyploidy and heterokaryosis in diverse organisms using read sets sequenced to greater than 50x whole-genome coverage. However, Sequencing to adequate depth is costly if applied to multiple individuals or large genomes. ResultsWe developed VCFvariance.pl to utilize the variance of allele balance to infer polyploidy and/or heterokaryosis at low sequence coverage. This analysis requires as little as 10x whole-genome coverage and reduces the allele balance profile down to a single value, which can be used to determine if an individual has two or more haplotypes. This approach was validated on simulated, synthetic, and authentic read sets from an oomycete, fungus, and plant. The approach was deployed to ascertain the genome status of multiple isolates of Bremia lactucae and Phytophthora infestans. Availability and implementationVCFvariance.pl is a Perl script available at https://github.com/kfletcher88/VCFvariance.

bioinformatics↗

Stereo-specific Lasofoxifene Derivatives Reveal the Interplay between Estrogen Receptor Alpha Stability and Antagonistic Activity in ESR1 Mutant Breast Cancer Cells

Chemical manipulation of estrogen receptor alpha ligand binding domain structural mobility tunes receptor lifetime and influences breast cancer therapeutic activities. Selective estrogen receptor modulators (SERMs) extend ER cellular lifetime, accumulation, and are antagonists in the breast and agonists in the uterine epithelium and/or in bone. Selective estrogen receptor degraders (SERDs) reduce ER cellular lifetime/accumulation and are pure antagonists. Activating somatic ESR1 mutations Y537S and D538G enable resistance to first-line endocrine therapies. SERDs have shown significant activities in ESR1 mutant setting while few SERMs have been studied. To understand whether chemical manipulation of ER cellular lifetime and accumulation influences antagonistic activity, we synthesized a series of methylpyrollidine lasofoxifene derivatives that maintained the drugs antagonistic activities while uniquely tuning ER cellular accumulation. These molecules were examined alongside a panel of antiestrogens in live cell assays of ER cellular accumulation, lifetime, SUMOylation, and transcriptional antagonism. High-resolution x-ray crystal structures of WT and Y537S ER ligand binding domain in complex with the methylated lasofoxifene derivatives, SERMs, and SERDs show that molecules that favor a highly buried helix 12 conformation achieve the greatest transcriptional suppression activities. Together these results show that chemical reduction of ER cellular lifetime does not necessarily correlate with transcriptional antagonism in ESR1 mutated breast cancer cells. Importantly, our approach shows how minor chemical additions modulate receptor cellular lifetime while maintaining other activities to achieve desired SERM or SERD profiles. SIGNIFICANCEThis study shows that antiestrogens that enforce a wild-type-like antagonist conformation demonstrate improved therapeutic activities in hormone-resistant breast cancer cells harboring Y537S and D538G ESR1.

cancer biology↗

Structural basis of target DNA recognition by CRISPR-Cas12k for RNA-guided DNA transposition

The type V-K CRISPR-Cas system, featured by Cas12k effector with a naturally inactivated RuvC domain and associated with Tn7-like transposon for RNA-guided DNA transposition, is a promising tool for precise DNA insertion. To reveal the mechanism underlying target DNA recognition, we determined a cryo-EM structure of Cas12k from cyanobacteria Scytonema hofmanni in complex with a single guide RNA (sgRNA) and a double-stranded target DNA. Coupled with mutagenesis and in vitro DNA transposition assay, our results revealed mechanisms for the recognition of the GGTT PAM sequence and the structural elements of Cas12k critical for RNA-guided DNA transposition. These structural and mechanistic insights should aid in the development of type V-K CRISPR-transposon systems as tools for genome editing.

molecular biology↗

Noise-Transfer2Clean: Denoising cryo-EM images based on noise modeling and transfer

MotivationCryo-electron microscopy (cryo-EM) is a widely-used technology for ultrastructure determination, which constructs the three-dimensional (3D) structures of protein and macromolecular complex from a set of two-dimensional (2D) micrographs. However, limited by the electron beam dose, the micrographs in cryo-EM generally suffer from extremely low signal-to-noise ratio (SNR), which hampers the efficiency and effectiveness of downstream analysis. Especially, the noise in cryo-EM is not simple additive or multiplicative noise whose statistical characteristics are quite different from the ones in natural image, extremely shackling the performance of conventional denoising methods. ResultsHere, we introduce the Noise-Transfer2Clean (NT2C), a denoising deep neural network (DNN) for cryo-EM to enhance image contrast and restore specimen signal, whose main idea is to improve the denoising performance by correctly discovering the noise model of cryo-EM images and transferring the statistical nature of noise into the denoiser. Especially, to cope with the complex noise model in cryo-EM, we design a contrast-guided noise and signal re-weighted algorithm to achieve clean-noisy data synthesis and data augmentation, making our method authentically achieve signal restoration based on noises true properties. To our knowledge, NT2C is the first denoising method that resolves the complex noise model in cryo-EM images. Comprehensive experimental results on simulated datasets and real datasets show that NT2C achieved a notable improvement in image denoising and specimen signal restoration, comparing with the state-of-art methods. A real-world case study shows that NT2C can improve the recognition rate on hard-to-identify particles by 19% in the particle picking task.

bioinformatics↗