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Search indexed bioRxiv preprints in genomics, neuroscience, cell biology and bioinformatics. Read source abstracts and check manuscript versions; preprints are not peer reviewed.

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At least 379 records · Page 21Linked to original sources

Rapid Therapeutic Recommendations in the Context of a Global Public Health Crisis using Translational Bioinformatics Approaches: A proof-of-concept study using Nipah Virus Infection

We live in a world of emerging new diseases and old diseases resurging in more aggressive forms. Drug development by pharmaceutical companies is a market-driven and costly endeavor, and thus it is often a challenge when drugs are needed for diseases endemic only to certain regions or which affect only a few patients. However, biomedical open data is accessible and reusable for reanalysis and generation of a new hypotheses and discovery. In this study, we leverage biomedical data and tools to analyze available data on Nipah Virus (NiV) infection. NiV infection is an emerging zoonosis that is transmissible to humans and is associated with high mortality rates. In this study, explored the application of computational drug repositioning and chemogenomic enrichment analyses using host transcriptome data to match drugs that could reverse the virus-induced gene signature. We performed analyses using two gene signatures: i) A previously published gene signature (n=34), and ii) a gene signature generated using the characteristic direction method (n= 5,533). Our predictive framework suggests that several drugs including FDA approved therapies like beclometasone, trihexyphenidyl, S-propranolol etc. could modulate the NiV infection induced gene signatures in endothelial cells. A target specific analysis of CXCL10 also suggests the potential application of Eldelumab, an investigative therapy for Crohns disease and ulcerative colitis, as a putative candidate for drug repositioning. To conclude, we also discuss challenges and opportunities in clinical trials (n-of-1 and adaptive trials) for repositioned drugs. Further follow-up studies including biochemical assays and clinical trials are required to identify effective therapies for clinical use. Our proof-of-concept study highlights that translational bioinformatics methods including gene expression analyses and computational drug repositioning could augment epidemiological investigations in the context of an emerging disease with no effective treatment.

microbiology↗

Targeting microbial arsenic resistance genes: a new bioinformatic toolkit informs arsenic ecology and evolution in soil genomes and metagenomes

Environmental resistomes include transferable microbial genes. One important resistome component is resistance to arsenic, a ubiquitous and toxic metalloid that can have negative and chronic consequences for human and animal health. The distribution of arsenic resistance and metabolism genes in the environment is not well understood. However, microbial communities and their resistomes mediate key transformations of arsenic that are expected to impact both biogeochemistry and local toxicity. We examined the phylogenetic diversity, genomic location (chromosome or plasmid), and biogeography of arsenic resistance and metabolism genes in 922 soil genomes and 38 metagenomes. To do so, we developed a bioinformatic toolkit that includes BLAST databases, hidden Markov models and resources for gene-targeted assembly of nine arsenic resistance and metabolism genes: acr3, aioA, arsB, arsC (grx), arsC (trx), arsD, arsM, arrA, and arxA. Though arsenic related genes were common, they were not universally detected, contradicting the common conjecture that all organisms have them. From major clades of arsenic related genes, we inferred their potential for horizontal and vertical transfer. Different types and proportions of genes were detected across soils, suggesting microbial community composition will, in part, determine local arsenic toxicity and biogeochemistry. While arsenic related genes were globally distributed, particular sequence variants were highly endemic (e.g., acr3), suggesting dispersal limitation. The gene encoding arsenic methylase arsM was unexpectedly abundant in soil metagenomes (median 48%), suggesting that it plays a prominent role in global arsenic biogeochemistry. Our analysis advances understanding of arsenic resistance, metabolism, and biogeochemistry, and our approach provides a roadmap for the ecological investigation of environmental resistomes.

microbiology↗

Bioinformatic screening of genes present only in well regenerating vertebrates reveals novel FGF and purinergic signaling modulator - c-Answer

The genetic basis of higher regenerative capacity of fishes, amphibians and reptiles compared to birds and mammals is still poorly understood. Though it is thought to be a result of restructuring in the regulatory network of a static set of genes, we argued that it could be due to the loss of genes essential for regeneration. In the present work, we formulate a bioinformatic approach to systematic search for the such genes. Having identified them, we further investigated one we dubbed \"c-Answer\", which encodes a membrane protein, regulating the regeneration of body appendages and the telencephalic development through binding to FGFR and P2Y1 receptors and promoting MAPK/ERK and purinergic signaling. The obtained data suggest that elimination of c-Answer in the ancestors of warm-blooded animals conditioned the decreased activity of at least two signaling pathways, which in turn could contribute to changes in mechanisms that regulate the forebrain development and regeneration.

developmental biology↗

Hypoxia on vhl-deficient cells to obtain hif related genes through bioinformatics analysis.

Vhl is responsible for degrading the transcription factor hif-1. Hif-1 transcription factors drive changes in hypoxic gene expression to adapt cells to exposure to hypoxic environments. This study hopes to analyze the effect of hypoxia on the vhl-deficient cells to obtain hif regulated genes through bioinformatics analysis. The top ten genes evaluated by connectivity degree in the PPI network were identified. CDK1, CTNNB1, NHP2, CCNA2, CTNNB1, MRPL16, CCND1 were down-regulated. CDK1, RPL12, RPL17, RPL27, RPS10 were up-regulated.

cell biology↗

Bioinformatic analysis of metastasis-associated metabolic landscape reveals an oncogenic role for the transsulfuration pathway

Cancer metastasis is a leading cause of cancer-related deaths, while its underlying mechanisms remain incompletely understood. To colonize distant organs, cancer cells reprogram their metabolism to adapt to diverse environmental challenges. Therefore, elucidating the metabolic pathways that drive cancer metastasis will uncover novel biomarkers and therapeutic targets. In this study, we integrated published datasets and systematically analyzed metabolites across multiple cancer cell lines. This large-scale bioinformatic analysis revealed distinct metabolites and metabolic pathways associated with organ-specific metastasis, and underscored the crucial role of tissue of origin in shaping the metabolic landscape of metastatic tumors. Notably, the transsulfuration pathway (also known as the cysteine and methionine metabolism) was strongly enriched in cancer cells with high metastatic potential. We validated this finding in pancreatic cancer, where the pathway enzyme cystathionine {beta}-synthase (CBS) and its metabolic products were highly expressed in metastatic cancer cells. Targeting the transsulfuration pathway either by methionine deprivation or pharmacological inhibition of CBS significantly impaired the migration and invasion of metastatic pancreatic cancer cells. Taken together, our study not only provides a global view of the altered metabolic landscape in metastasis, but also identifies the transsulfuration pathway as an oncogenic driver and a therapeutic target for pancreatic cancer metastasis.

cancer biology↗

To FRET or Not to FRET: Bioinformatics and Fluorescence Spectroscopy suggest that Reduced Tryptophan to Heme Energy Transfer Facilitates Lignin Degradation in Class II Peroxidases

A key step in the evolution of lignin-degrading enzymes is revealed by the observation that, unlike other heme-proteins studied to date, Class II peroxidases exhibit minimal energy transfer from tryptophan (Trp) to heme residues. Bioinformatics analyses and molecular dynamics simulations of Class II (MnP and VP) and Class III (horseradish peroxidase, HrP) structures indicate that the Trp residue in HrP has the highest orientational factor and fluorescence resonance energy transfer (FRET) efficiency. By contrast, Trp residues in MnP and VP display low FRET efficiency due to unfavorable orientation factors despite their proximity to the heme. Steady-state fluorescence experiments confirmed this low FRET efficiency, showing strong emission in MnP and VP but weak emission in HrP. This decreased Trp-to-heme energy transfer appears to minimize competition between direct FRET and long-range electron transfer (LRET), allowing electrons to flow from bulky lignin substrates to the heme center. Such a mechanism likely provided a selective advantage during the evolution of Class II peroxidases, facilitating efficient lignin degradation at the enzyme surface. HighlightsClass II peroxidases show reduced Trp-to-heme FRET compared with HRP MD simulations reveal unfavorable Trp-heme orientation in VP and MnP Low FRET correlates with strong Trp fluorescence in VP and MnP Reduced FRET favors long-range electron transfer (LRET) during lignin oxidation Findings suggest an evolutionary adaptation in lignin-degrading peroxidases O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=128 SRC="FIGDIR/small/697144v1_ufig1.gif" ALT="Figure 1000"> View larger version (36K): org.highwire.dtl.DTLVardef@f8b3a8org.highwire.dtl.DTLVardef@1db18a4org.highwire.dtl.DTLVardef@12ebf1dorg.highwire.dtl.DTLVardef@54712_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

Comparative Performance of Portable DNA Extraction Protocols and Bioinformatics Workflows for Rapid Detection of Pathogens and Antimicrobial Resistance Using Oxford Nanopore Sequencing.

Oxford Nanopore technology (ONT) enables rapid, portable pathogen identification and detection of antimicrobial resistance (AMR). Still, the reliability of downstream genomic analyses is highly dependent on DNA extraction quality, particularly in resource-limited settings. This study comparatively evaluated four portable bacterial DNA extraction protocols, derived from three commercial kits, to determine their impact on nanopore sequencing performance, bioinformatics workflow completion, and field deployability. Six Gram-negative bacterial isolates (Escherichia coli, n= 4; Pseudomonas sp., n= 1; and Salmonella sp., n= 1) were processed using four extraction protocols: SwiftX DNA, SwiftX DNA with proteinase K (ProtK), SwiftX ParaBact, and NucleoSpin Microbial. Twenty-four DNA extracts (6 isolates x 4 protocols) were sequenced on a single multiplexed MinION R10.4.1 flow cell. Sequencing data were analysed using validated Galaxy-based generic and species-specific pipelines, with workflow completion defined as successful progression through quality control, assembly, virulence, plasmid and AMR detection modules. DNA purity varied substantially by extraction protocol and was strongly associated with workflow success. NucleoSpin Microbial achieved 100% workflow completion, SwiftX ParaBact achieved 83%, while both SwiftX DNA-based protocols failed to complete full workflows. Higher A260/A280 ratios were strongly correlated with successful workflow completion (Spearmans {rho} = 0.767, p < 0.0001). Importantly, key AMR genes required to classify isolates as multidrug resistant were consistently detected using both NucleoSpin Microbial and SwiftX ParaBact extractions. However, NucleoSpin Microbial assemblies showed significantly higher contiguity and enabled broader and more complete detection of virulence factors, pathogenicity islands, plasmid replicons, and accessory AMR genes, reflecting enhanced genomic resolution. IMPORTANCERapid whole-genome sequencing is increasingly used to detect antimicrobial resistance and guide public health responses, but its reliability depends strongly on how bacterial DNA is extracted. In this study, we show that DNA extraction method choice has a major impact on Oxford Nanopore sequencing performance across clinically relevant bacteria. While silica-column-based extraction maximised genomic completeness and analytical depth, paramagnetic bead-based reverse purification offered superior portability with sufficient resolution for frontline AMR surveillance. These findings highlight a practical trade-off between field deployability and high-resolution genomic characterisation in low-resource settings.

genomics↗

Comprehensive bioinformatic analysis reveals novel potential diagnostic biomarkers associated with monocytes in osteoporosis

Osteoporosis affects millions of women globally. In this study, we applied bioinformatics methods to screen for novel diagnostic biomarkers of osteoporosis in women using the GSE62402 and GSE56814 datasets. PCSK5, ZNF225, and H1FX were used to construct a diagnostic model. ROC, calibration, and decision curve analyses were performed to assess the diagnostic performance on the training (GSE56814) and external (GSE56815) datasets. The expression level of model genes was validated in GEO datasets. Furthermore, five transcription factors (ETS1, NOTCH1, MAZ, ERG, and FLI1) were identified as common upstream regulators of model genes. PCSK5, ZNF225, and H1FX serve as novel diagnostic biomarkers, providing new insights into the pathogenesis of and treatment strategies for osteoporosis in women.

genetics↗

COMBO-RATE: An experimentally validated bioinformatic tool to identify promiscuous HLA restrictions

Defining HLA restriction of T cell epitopes is essential for understanding immune responses in infectious disease, autoimmunity, and vaccine design. Current bioinformatic programs, including the IEDB RATE tool, enable inference of single-HLA restrictions from immune response data of HLA-typed donors. However, T cell epitopes are frequently presented by multiple HLA alleles, a phenomenon termed promiscuous restriction, limiting the utility of single-allele approaches. To address this limitation, we developed COMBO-RATE, an extension of RATE that systematically evaluates combinations of HLA alleles to identify multi-allelic restriction patterns. Analysis of three independent datasets spanning distinct antigen systems and different epitope discovery strategies revealed that promiscuous restriction is a near-universal feature of immunodominant epitopes. Focusing on the 43 immunodominant CD4 T cell epitopes identified in a B. pertussis genome-wide screen, COMBO-RATE outperformed conventional RATE, identifying restrictions for 35 of 43 epitopes, compared to 24 by RATE alone, and uncovered 64 additional allele restrictions, including 29 unique alleles. Experimental validation using single-HLA transfected cell lines and antigen presentation assays confirmed COMBO-RATE-inferred restrictions, demonstrating that a single epitope can be independently presented by distinct HLA alleles. Overall, COMBO-RATE provides a robust and scalable framework for defining complete HLA restriction profiles from existing population response data, with important implications for the design of vaccines requiring broad HLA coverage across genetically diverse populations. This pipeline is available as both a Python package and a user-friendly web application.

immunology↗

A Bioinformatic Pipeline for Consensus Taxonomic Classification of Long-Read Amplicons

Characterizing community composition is fundamental to understanding microbial community function. Recent advances in Oxford Nanopore Technology (ONT) long-read sequencing now allow community profiling using full-length gene amplicons, affording better taxonomic resolution than standard short-amplicon Illumina sequencing. However, robust ONT-compatible profiling workflows are lacking. To address this, we have created the Amplicon Consensus Taxonomy (ACT) pipeline for classifying long-read amplicons. ACT combines output from three existing pipelines - Emu, Sintax, and LACA - to leverage the strengths of each while offsetting their individual limitations. We also developed the ACT database (ACT-DB), a sequence-similarity-aware reference database that clusters highly similar sequences into multi-taxa groups to reduce overclassification. We benchmarked ACT performance against Emu and Sintax using a defined simple mock community, simulated datasets, and a complex rhizosphere community supplemented with novel species. While ACT exhibited generally comparable or superior performance across datasets, ACT demonstrated a marked advantage over Emu and Sintax in identifying novel and low-abundance taxa in both simple and complex communities, resulting in significantly higher species-richness estimates that better reflected those observed in prior Illumina amplicon studies. Furthermore, by clustering ambiguous reference sequences, ACT-DB allowed ACT to resolve reads to meaningful multi-species groups, improving resolution without coercing artificial precision. Together, ACT and ACT-DB form a robust long-read amplicon profiling workflow that confidently identifies known species while reducing overclassification and preserving low-abundance and unknown taxa. IMPORTANCEMicrobial communities are frequently characterized by amplicon sequencing of marker genes, such as the bacterial 16S rRNA gene and fungal ITS region. Historically, the standard profiling method has been Illumina sequencing of 200-300 bp amplicons, but improved accuracy of ONT long-read sequencing means it is now possible to sequence amplicons spanning full genes of any size, prompting the need for tools optimized for long amplicons. Here, we describe the ACT bioinformatic pipeline for assigning taxonomy to amplicons of any length. We evaluated ACT performance using full-length 16S amplicon data relative to that of two commonly used pipelines. Additionally, we developed a sequence ambiguity-aware ACT database (ACT-DB) of 16S rRNA sequences to further improve classification accuracy and resolution.

microbiology↗

Hot Pursuit: Bioinformatic and Biochemical Characterization of a Hyperthermophilic Family B DNA Polymerase from Pyrolobus fumarii A1

Thermostable DNA polymerases are indispensable tools in molecular biology, yet enzymes from the most extreme hyperthermophiles remain largely uncharacterized. Here, we report the biochemical and structural characterization of a family B DNA polymerase from Pyrolobus fumarii A1 (Pyrfu pol), one of the most thermoresistant archaea described to date. The enzyme was efficiently overproduced in E. coli Rosetta 2(DE3)[pLysS] and purified to homogeneity using a two-step protocol that combined heat treatment with immobilized metal affinity chromatography (IMAC). Bioinformatic analysis confirmed the canonical family B architecture, while AlphaFold-based structural modeling and comparative analysis with mesophilic RB69 DNA polymerase revealed a well-conserved structural core alongside thermoadaptive features. Radiolabel incorporation assays demonstrated enzymatic activity over a broad ionic strength range and an absolute requirement for Mg2{square}. PCR-based optimization confirmed these findings and revealed broad pH tolerance (6.5-11.0). Notably, Tris inhibited radiolabel-based assays (pH 7.0) yet proved essential for efficient PCR amplification (pH 8.5), suggesting a context-dependent role of buffer composition in polymerase activity. Processivity assays confirmed amplification of DNA fragments up to approximately 8,000 bp. Replication fidelity, assessed by the lacZ-based assay, showed a 2.9-fold improvement over Taq polymerase. Urea-nanoDSF yielded an exceptional melting temperature of 105.9 {+/-} 0.08 {degrees}C. Pyrfu pol also demonstrated tolerance to common PCR inhibitors, highlighting its potential utility in molecular biology applications. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=80 SRC="FIGDIR/small/734501v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@1a94cb0org.highwire.dtl.DTLVardef@1e9e1b9org.highwire.dtl.DTLVardef@1e240d8org.highwire.dtl.DTLVardef@10f47b9_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

OTTR-CLASH: improved biochemical and bioinformatic identification of Argonaute 2-mediated microRNA-target RNA interactions

Various methods have detected miRNA-target interactions via immunoprecipitation of UV-crosslinked Argonaute ribonucleoprotein complexes, followed by intermolecular ligation of bound miRNAs to target strands, forming chimeric RNAs. To date, these methods have relied on conventional viral reverse transcriptases (RTs) to generate cDNAs for sequencing. However, crosslinked RNAs often retain adducts after purification, which can make them poor templates for viral RTs. Here, we adapted OTTR (Ordered Two-Template Relay) techniques to generate cDNAs from Ago2-bound RNAs. OTTR makes use of a modified retroelement-encoded RT, which is strongly processive even on templates with modifications or adducts. We show that this "OTTR-CLASH" method increases the frequency of generating chimeric RNAs compared to previous methods. We also developed an improved bioinformatic pipeline for analysis of these data, and we use this to catalog miRNA-target interactions not previously described in the literature. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=147 HEIGHT=200 SRC="FIGDIR/small/738487v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@16d62f8org.highwire.dtl.DTLVardef@7c8da4org.highwire.dtl.DTLVardef@13727fborg.highwire.dtl.DTLVardef@21f443_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

Integrated Bioinformatics Analysis Reveals Candidate Hub Genes and Regulatory Networks Associated with Preeclampsia

Preeclampsia (PE) is a severe pregnancy-associated hypertensive disorder and a major contributor to maternal and perinatal morbidity and mortality. The mechanisms of PE pathogenesis are not yet understood. This paper aims to explore candidate PE-associated biomarkers and regulatory mechanisms using bioinformatics analysis of placental transcriptomic datasets. We downloaded placental transcriptomic datasetsGSE203507 and GSE148241 from GEO and investigated differentially expressed genes(DEGs) between PE and control samples. We performed Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Disease Ontology (DO), and protein-protein interaction (PPI) analyses to characterize the potential role, disease associations, and interaction networks of the DEGs. We validated the mRNA expression patterns of candidate hub genes using two independent placental transcriptomic datasets, GSE143966 and GSE114691.We identified 263 DEGs in the discovery analysis and further obtained 150 overlapping DEGs including80 upregulated genes and 70 downregulated genes, for downstream analysis. We then identified eight candidate hub genes: OPRK1, OXGR1, HCAR3, CCR5, HCAR2, CXCL1, FPR3, and SSTR1using Meta scape software(v3.5.20260201). In the validation phase, most candidate hub genes showed broadly consistent mRNA expression trends across GSE114691 and GSE143966, while FPR3 showed weaker cross-dataset consistency. These findings provide candidate PE-associated genes and regulatory pathways for further experimental and clinical validation..

bioengineering↗

A new bioinformatic analysis highlights a subpopulation of mitochondria with highly methylated DNA present in oocytes, early embryos and blood.

Abstract Background: Mitochondria are present in virtually all eukaryotic cells, yet several aspects of their function remain poorly understood. Although their activity depends on more than 1,000 genes, the mitochondrial genome encodes only 38 genes, including 13 protein-coding genes. Mitochondrial DNA (mtDNA) differs substantially from nuclear DNA (nDNA), notably because it lacks histones and contains virtually no intronic or intergenic sequences. DNA methylation of mtDNA has been reported in oocytes, embryos, and various human diseases, occurring not only at CpG sites but also in other cytosine contexts. However, average methylation levels are generally considered to be very low. By re-examining methylation patterns at the individual-read level, this study highlights marked heterogeneity in mtDNA methylation and proposes a potential explanation for previously conflicting observations. Results: Using bovine oocytes and embryos, as well as blood samples, we analyzed multiple datasets generated by whole-genome EM-seq, which captures both nuclear and mitochondrial DNA methylation. Sequenced reads were separated and analyzed individually to quantify methylation levels either at specific cytosines or across all cytosines within each read. The resulting distributions consistently displayed a U-shaped pattern, where the vast majority of reads were completely unmethylated while a small subset was highly methylated. The proportion of methylated reads increased from oocytes to 8-16 cell embryos, then declined in blastocysts and blood samples. This distribution pattern was highly conserved among samples from the same developmental stage and remained remarkably similar across embryonic stages, while differing from blood. When only heavily methylated reads (>50% methylation) were analyzed, their methylation profiles along the 16 kb mitochondrial genome were even more conserved across tissues. These observations suggest the existence of distinct mtDNA populations with different methylation states that are largely obscured by conventional bioinformatic approaches based on averaged methylation levels. Conclusions: The identification of highly methylated mtDNA reads reveals heterogeneity among mtDNA molecules and raises the hypothesis that these molecules may be associated with functionally distinct mitochondrial states. The heavily methylated population, termed "mitoQueens," may exhibit reduced gene expression, lower metabolic activity, decreased reactive oxygen species (ROS) production, and potentially reduced mutation accumulation. In contrast, the predominantly unmethylated population, referred to as "mitoWorkers," would be responsible for most energy production and cellular functions. Similar to stem cells, "Queen" mitochondria may represent a reserve population that can be activated under specific conditions and preserved for transmission to future generations.

developmental biology↗

WMP: A novel comprehensive wheat miRNA database, including related bioinformatics software

MicroRNAs (miRNAs) are emerging as important post tran-scriptional regulators that may regulate key plant genes responsible for agronomic traits such as grain yield and stress tolerance. Several studies identified species and clades specific miRNA families associated with plant stress regulated genes. Here, we propose a novel resource that provides data related to the expression of abiotic stress responsive miRNAs in wheat, one of the most important staple food crops. This database allows the query of small RNA libraries, including in silico predicted wheat miRNA sequences and the expression profiles of small RNAs identified from those libraries. Our database also provides a direct access to online miRNA prediction software tuned to de novo miRNA detection in wheat, in monocotyledon clades, as well as in other plant species. These data and software will facilitate multiple comparative analyses and reproducible studies on small RNAs and miRNA families in plants. Our web-portal is available at: http://wheat.bioinfo.uqam.ca.

Bioinformatics↗

Understanding properties of the master effector of phage shock operon in Mycobacterium tuberculosis via bioinformatics approach

The phage shock protein (Psp) is a part of the Psp operon, which assists in safeguarding the survival of bacterium in stress and shields the cell against proton motif force challenge. It is strongly induced by bacterium allied phages, improperly localized mutant porins and various other stresses. Master effector of the operon, PspA has been modeled and simulated, illustrating how it undergoes significant conformational transition at the far end in Mycobacterium tuberculosis. Association of this key protein of the operon influences action of Psp system on the whole. We are further working on the impact of phosphorylation perturbation and changes in the structure of PspA during complex formation with other moieties of interest.

Bioinformatics↗

Exploratory bioinformatics analysis reveals importance of "junk" DNA in early embryo development

BackgroundInstead of testing predefined hypotheses, the goal of exploratory data analysis (EDA) is to find what data can tell us. Following this strategy, we re-analyzed a large body of genomic data to investigate how the early mouse embryos develop from fertilized eggs through a complex, poorly understood process.\n\nResultsStarting with a single-cell RNA-seq dataset of 259 mouse embryonic cells from zygote to blastocyst stages, we reconstructed the temporal and spatial dynamics of gene expression. Our analyses revealed similarities in the expression patterns of regular genes and those of retrotransposons, and the enrichment of transposable elements in the promoters of corresponding genes. Long Terminal Repeats (LTRs) are associated with transient, strong induction of many nearby genes at the 2-4 cell stages, probably by providing binding sites for Obox and other homeobox factors. The presence of B1 and B2 SINEs (Short Interspersed Nuclear Elements) in promoters is highly correlated with broad upregulation of intracellular genes in a dosage-and distance-dependent manner. Such enhancer-like effects are also found for human Alu and bovine tRNA SINEs. Promoters for genes specifically expressed in embryonic stem cells (ESCs) are rich in B1 and B2 SINEs, but low in CpG islands.\n\nConclusionsOur results provide evidence that transposable elements may play a significant role in establishing the expression landscape in early embryos and stem cells. This study also demonstrates that open-ended, exploratory analysis aimed at a broad understanding of a complex process can pinpoint specific mechanisms for further study.\n\nMajor findingO_LISingle-cell RNA-seq data enables estimation of retrotransposon expression during PD\nC_LIO_LISimilar expression dynamics of retrotransposons and regular genes during PD\nC_LIO_LILong terminal repeats may be essential for the 1st wave of gene expression\nC_LIO_LIObox homeobox factors are possible regulators of PD, upstream of Zscan4\nC_LIO_LISINE repeats predict expression of nearby genes in murine, human and bovine embryos\nC_LIO_LIExploratory analysis of large single-cell data pinpoints developmental pathways\nC_LI

Bioinformatics↗

Designing Effective small interfering RNA for Post-Transcriptional Silencing of Human GREM1: A Comprehensive Bioinformatics Approach

Human gremlin-1 is a physiologically versatile signaling molecule that has been associated with several human diseases including cancer. The ability of gremlin-1 to induce fibrosis in organs and transduce angiogenesis makes it a target for cancer therapy. RNAi-based therapy has proven to be very efficient and specific in tumor growth inhibition. The efficacy and specificity of siRNA-mediated gene silencing depends on the designing approaches. Here, empirical guidelines for siRNA design and comprehensive target site availability analysis were used to select effective siRNA from a plethora of potential candidates designed using several computation algorithms. Then, the selected siRNA candidates were subjected to stringent similarity searches in order to obtain siRNA candidates with reduced off-target effects (high specificity). The best candidates were compared to experimentally successful gremlin-1 siRNAs in order to predict the silencing potency of the selected siRNAs. siRNA-6 (sense strand: 5-CCAAGAAAUUCACUACCAU-3), siRNA-7 (sense strand: 5-CCAUGAUGGUCACACUCAA-3) and siRNA-47 (sense strand: 5-GGCCCAGCACAAUGACUCA-3) were predicted to be highly effective siRNA candidates for gremlin-1 silencing. These siRNAs can be considered for RNAi-based therapy because off-target effects are predicted to be minimal.

bioinformatics↗