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At least 37 records · Page 2Linked to original sources

Genomic hallmarks of depot medroxyprogesterone acetate-associated meningiomas.

BACKGROUND: Population-based studies have linked progestin exposure to increased meningioma risk. However, the molecular basis of meningiomas associated with depot medroxyprogesterone acetate (DMPA)-a common injectable contraceptive-remains undefined. METHODS: We performed an integrated clinicopathologic and genomic analysis of meningiomas from 10 women with long-term DMPA exposure. Tumors underwent histopathological analysis, targeted sequencing, and DNA methylation profiling. Data were integrated with reference cohorts (Baylor and Heidelberg) and analyzed through classifier assignment, consensus clustering, copy number analysis, differential methylation testing, and dimensionality reduction. RESULTS: Depot medroxyprogesterone acetate-associated meningiomas were all newly diagnosed, World Health Organization grade 1 tumors with a predilection for the anterior and central skull base (n = 6). Nine patients harbored multiple meningiomas. Four experienced regression of untreated meningiomas following DMPA cessation, while 5 demonstrated stabilization. Histopathology demonstrated relative overrepresentation of metaplastic morphology, an uncommon meningioma subtype. All DMPA-associated meningiomas mapped to benign molecular groups, and most exhibited low copy number alteration burden. Targeted sequencing revealed enrichment for TRAF7 mutations (n = 5), with no NF2 mutations detected. Eight tumors shared consensus cluster identity, with cohesive grouping on principal component analysis and t-distributed stochastic neighbor embedding. No differential methylation was identified at the progesterone receptor locus. CONCLUSIONS: Depot medroxyprogesterone acetate-associated meningiomas represent a recognizable phenotype within the broader NF2-wildtype/TRAF7-enriched spectrum of benign meningiomas, characterized by chromosomal stability, a shared methylation profile, tumor multiplicity, and regression or stabilization following DMPA cessation. While derived from a small single-institution cohort, these findings provide a molecular framework for understanding progestin-associated meningioma biology, reinterpreting epidemiologic literature, and informing population-level risk stratification.

Humans↗

Use of molecular probes to detect human cytomegalovirus and human immunodeficiency virus.

Human cytomegalovirus (HCMV) and human immunodeficiency virus (HIV) cause severe disease. The identification of these viruses in clinical specimens and understanding the progression of infection and diseases relating to HCMV and HIV are essential to develop effective means for treatment and prevention. Here we describe the application of molecular probes to the diagnosis and pathogenesis of HCMV and HIV. In situ hybridization and the amplification procedure of polymerase chain reaction are used to detect both viruses; these techniques have provided important information regarding the pathogenesis of HCMV and HIV. A new technique, target cycling, may also prove useful for the detection of viruses by enriching for target sequences. The continued application of molecular probes to pathogenetic studies of HCMV and HIV promises to further our knowledge of these viruses, and of their interaction.

Cytomegalovirus↗

Mapping DNA-protein interactions in large genomes by sequence tag analysis of genomic enrichment.

Identifying the chromosomal targets of transcription factors is important for reconstructing the transcriptional regulatory networks underlying global gene expression programs. We have developed an unbiased genomic method called sequence tag analysis of genomic enrichment (STAGE) to identify the direct binding targets of transcription factors in vivo. STAGE is based on high-throughput sequencing of concatemerized tags derived from target DNA enriched by chromatin immunoprecipitation. We first used STAGE in yeast to confirm that RNA polymerase III genes are the most prominent targets of the TATA-box binding protein. We optimized the STAGE protocol and developed analysis methods to allow the identification of transcription factor targets in human cells. We used STAGE to identify several previously unknown binding targets of human transcription factor E2F4 that we independently validated by promoter-specific PCR and microarray hybridization. STAGE provides a means of identifying the chromosomal targets of DNA-associated proteins in any sequenced genome.

Cells, Cultured↗

Developing and Benchmarking One Health Genomic Surveillance Tools for Influenza A Virus in Wastewater.

Influenza A viruses (IAV) remain a persistent One Health threat, and whole-genome sequencing from wastewater offers a promising surveillance tool. However, IAV is at low abundance in wastewater, making it difficult to sequence. We benchmarked four targeted enrichment methods suited for whole-genome sequencing including custom and off-the-shelf amplicon and probe-based methods. Our custom HA tiled-amplicon panel was sensitive, fast, and cost-effective, making it suitable for monitoring low-abundance seasonal variants of known subtypes. However, its reliance on conserved and intact primer-binding sites limited primer design to fewer subtypes. A previously published universal amplicon method targeted all IAV subtypes, but it performed poorly in wastewater due to its reliance on intact genome segments. Probe-capture methods were resilient to RNA degradation and mismatches, potentially enabling broader surveillance and detection of emerging strains. However, probes were costly, labor-intensive, and less sensitive than tiled-amplicon. When testing compatibility of sequencing methods with upstream virus concentration and extraction methods, ultrafiltration-based virus concentration outperformed large-volume direct extraction with all four sequencing methods. This set of benchmarking comparisons and custom panels provides needed information for the translation of IAV genomic sequencing into a routine component of wastewater surveillance.

Journal Article↗

A subtractive hybridisation method for the enrichment of moderately induced sequences.

Moderately induced genes often escape detection in conventional subtraction hybridisation cloning. Here a modification of a phagemid subtraction protocol is described that overcomes this problem. The protocol uses low ratio hybridisation of driver to target sequences to allow enrichment of the sequences of interest, and back-hybridisation of the subtracted sequences with induced sequences to reduce the accumulation of false positive clones. The procedure takes advantage of the quantitative representation of cellular RNA populations in cDNA libraries, therefore, they may serve not only as renewable sources of driver and target sequences, but also as sources of population cRNAs used in northern blots and differential Southern blots.

Animals↗

Identification of glyceraldehyde-3-phosphate dehydrogenase by protein sequencing in the rat postsynaptic density fraction.

Although many abundant proteins of the postsynaptic density (PSD) are known, most of the less abundant and minor PSD proteins await identification. In this work we attempted to identify a 37 kDa protein, which represented less than 1% of the total n-octyl glucoside (NOG)-insoluble proteins, by protein sequencing. To enrich the target protein, the NOG-insoluble fraction was first electrophoresed in 6% SDS-polyacrylamide gels, and the proteins smaller than 45 kDa compressed in the gel from were electroeluted and subsequently reseparated in 10% SDS-gels. This procedure enriched the target protein to represent about 25% of the eluted proteins. Peptides were generated by digesting the target protein with trypsin directly in the gel and purified by a reverse phase high performance liquid chromatography (HPLC). Two peptides were determined for amino acid sequences. A database search revealed that both sequence were found in glyceraldehyde-3-phosphate dehydrogenase (GAPDH) with a minor discrepancy, indicating the the 37 kDa protein in the NOG-insoluble pSD fraction is an isoform of GAPDH.

Amino Acid Sequence↗

Transcript-guided targeted cell enrichment for scalable single-nucleus RNA sequencing.

Large-scale single-cell atlases have revealed many aging- and disease-associated cell types, yet these populations are often underrepresented in heterogeneous tissues, limiting detailed molecular analyses. To address this, we developed EnrichSci-a scalable, microfluidics-free platform that combines hybridization chain reaction RNA fluorescence in situ hybridization (FISH) with combinatorial indexing to profile single-nucleus transcriptomes of target cell types with full gene-body coverage. Applied to oligodendrocytes in the aging mouse brain, EnrichSci uncovered aging-associated molecular dynamics across distinct oligodendrocyte subtypes, revealing both shared and subtype-specific gene expression changes. Additionally, we identified aging-associated exon-level signatures missed by conventional gene-level analyses, highlighting post-transcriptional regulation as a critical dimension of cell-state dynamics in aging. By coupling transcript-guided enrichment with a scalable sequencing workflow, EnrichSci provides a versatile approach to decode dynamic regulatory landscapes in diverse cell types from complex tissues.

Animals↗

Portable metagenomics for preventive surveillance and outbreak control in livestock and poultry: Pathogen detection, resistome profiling, and antimicrobial stewardship.

Conventional diagnostics for livestock and poultry outbreaks commonly rely on culture or targeted PCR panels, which may be too slow or too narrow to guide early control decisions. Portable metagenomics, particularly real-time nanopore sequencing, offers a route to broad pathogen detection, antimicrobial-resistance gene profiling, and outbreak investigation within an integrated workflow. This implementation-focused review evaluates how near-point-of-care metagenomics may support preventive veterinary medicine through earlier detection, surveillance, cohorting, biosecurity decisions, and antimicrobial stewardship. We synthesize sample-to-answer workflows for enteric and respiratory disease in food-producing animals, including sampling, nucleic-acid extraction, host depletion or target enrichment, library preparation, sequencing, bioinformatics, quality control, and interpretation. Applications in calf diarrhea, bovine respiratory disease, poultry outbreaks, mastitis, and resistome monitoring are considered alongside the central limitation that detection alone does not establish causation. Pathogen and resistance-gene signals must therefore be interpreted with clinical signs, lesions, epidemiology, controls, and confirmatory testing. We also propose a minimum reporting checklist, intended as a practical framework rather than a validated consensus standard. Portable metagenomics is not a replacement for conventional diagnostics, but appropriately validated workflows can reduce uncertainty during time-sensitive outbreaks and support more judicious antimicrobial use.

Animals↗

[Kinetic analysis for subtractive hybridization of transcripts].

A theoretical analysis of kinetics of two subtractive cDNA hybridizations has been carried out: hybridisation of an excess of denatured double-stranded cDNA (driver) with denatured double-stranded cDNA (tracer) containing some sequences (targets) missing from the driver, and hybridisation of denatured double-stranded tracer with denatured double-stranded driver unable to be renatured. Our calculations show that the first strategy requires several rounds of hybridisation for sufficient enrichment of tracer with target sequences of the low-abundant mRNA: in the first round the renatured fraction is removed, and in subsequent rounds the remaining single-stranded fraction cDNA is used and renatured fraction is collected. The second strategy makes it possible to sufficiently enrich non-reassociated fraction of tracer with minor fractions of target sequences in a single round of subtractive hybridisation.

DNA, Complementary↗

Identification and full genome sequencing of previously unknown sandfly-borne phleboviruses using a newly established capture-based next-generation sequencing approach.

Sandfly-borne phleboviruses cause febrile illness and neuroinvasive disease in humans. While infections are reported in the Mediterranean region, the discovery of previously unknown phleboviruses in sandflies from Kenya suggests a wider geographic distribution. Detection and characterization of novel phleboviruses are often hindered by low-quality and low-viral-load samples. We developed a capture-based target enrichment next-generation sequencing approach that showed a 99%-100% fold enrichment of viral genomes from primary material and provides a robust tool for generating complete genomes of both known and previously unknown viruses. From a collection of 15,652 sandflies in Kenya, we recovered seven complete coding sequences of Embossos, Bogoria, and Kiborgoch viruses, and of two previously unknown phleboviruses, which were named Sosoik and Shable viruses. Sosoik virus shared 83% amino acid identity in its RdRp gene with that of Bogoria virus, while Shable virus shared ca. 88% amino acid identity with viruses of the Salehabad serocomplex. Additionally, a reassortant of Shable virus was detected that possessed an M segment from an undescribed Ponticelli-like virus. DNA barcoding of blood-fed sandflies revealed several potentially novel Sergentomyia species and evidence of host-feeding on humans, livestock, and reptiles, suggesting possibilities for zoonotic transmission. Overall, our findings increase the known genetic diversity of Old World sandfly-borne phlebovirus species from 18 to 25 (by 38.9%), including the detection of viruses from all pathogenic sandfly-borne phlebovirus serocomplexes in East Africa, opening new horizons in disease ecology research.IMPORTANCEKnowledge of the genetic diversity of circulating pathogens is crucial for providing appropriate diagnostics and disease management. This study established a novel capture-based target enrichment next-generation sequencing approach that enabled the near-complete viral genome recovery from primary samples, while native NGS yielded negative or poor-quality results. In addition to the five recently discovered sandfly-borne phleboviruses in Kenya, two previously unknown phleboviruses were detected in sandflies from the same region. The viruses were detected in several sandfly species, which showed diverse host-feeding behaviors, including mixed feeding on humans and chickens. The study significantly advances the understanding of sandfly-borne phleboviruses by uncovering their broader geographic distribution and genetic diversity, particularly in East Africa, highlighting the importance of expanding surveillance efforts beyond traditionally studied regions.

Phlebovirus↗

The polymerase chain reaction: a new tool for the detection of minimal residual disease in haematological malignancies.

The polymerase chain reaction (PCR) is a novel technique for the in vitro amplification of specific short DNA fragments, which permits a selective and up to 10(7) fold enrichment of the target sequence. The method is increasingly being used for the molecular genetic analysis of hereditary, infectious and neoplastic disorders. The use of PCR for the detection of minimal residual disease in particular types of leukaemia or lymphoma, such as chronic myelogenous leukaemia expressing specific BCR/ABL-RNA and follicular non-Hodgkin lymphoma with the chromosomal translocation t(14;18) are reviewed. In acute lymphoblastic leukaemia clone-specific sequences from rearranged antigen receptor genes may be molecular markers suitable for amplification. Although PCR holds great promise for "molecular" staging and follow-up, several technical problems have to be kept in mind, and the clinical relevance of PCR-based evidence of minimal residual disease in haematological malignancies requires further investigation.

False Negative Reactions↗

Isolation of pathogen-induced Chinese cabbage genes by subtractive hybridization employing selective adaptor ligation.

We have developed a subtractive cloning method in which target sequences are effectively enriched by selective adaptor ligation and PCR after hybridization. In this method both tester and driver DNAs are digested with RsaI, ligated with the linker DNA containing a KpnI recognition site, and amplified by PCR. The tester DNA samples are divided into two aliquots, each digested with either RsaI or KpnI. The two DNA samples are then combined and hybridized with an excess of the driver DNA retaining the linker. After hybridization, the DNA mixture is ligated to a new adaptor compatible only with double-stranded tester/tester DNAs. Therefore, only the tester/tester is selectively amplified in subsequent PCR. This also leads to complete elimination of the tester DNA hybridized with driver DNA from the tester DNA population. Although our protocol employs enzymatic treatments, the efficiency of the enzymatic treatments does not affect the subtraction efficiency. This new subtractive enrichment method was applied to isolate Chinese cabbage defense-related genes induced by Pseudomonas syringae pv. tomato (Pst), which elicits a hypersensitive response in Chinese cabbage. After two or three rounds of subtractive hybridization, the sequences of enriched DNAs were determined and examined by BLAST analysis. Northern blot hybridization showed that 12 of the 19 genes analyzed were strongly induced by Pst treatment. Among the 12 Pst-induced genes five represent pathogenesis-related genes encoding PR1a, two chitinases, a thaumatin-like protein, and a PR4 protein. Other Pst-induced genes include two cytochrome P450 genes responsible for glucosinolate biosynthesis, a disease resistance gene homolog, and several genes encoding proteins with unknown functions.

Brassica rapa↗

Mannheimia haemolytica strain-level diversity in cattle populations.

High-resolution genomic characterization is essential for understanding diversity, pathogenicity, and transmission dynamics of bacterial pathogens. Mannheimia haemolytica (Mh) is the most consequential bacterial agent associated with bovine respiratory disease (BRD) in cattle, as a leading cause of morbidity, mortality, and antimicrobial use. Historically, BRD pathogens, including Mh, have been studied using culture or PCR approaches that provided limited ability to characterize fine-scale genomic variation across communities. Here, we evaluated target-enriched (TE) shotgun sequencing, a culture-independent method capable of strain-level resolution within metagenomic data, for detecting and characterizing Mh in comparison with qPCR and 16S rRNA gene sequencing. Nasal swabs (10 individual and 2 composited DNA samples per pen) and environmental samples (three ropes hung on pen rails and three water bowl swabs per pen) were collected from four pens in each of five distinct cattle populations. DNA was extracted for TE sequencing to identify Mh at both species and genomic sequence variant (GSV) levels, and to characterize antimicrobial resistance genes across the bacterial communities. qPCR was performed to quantify Mh genome copies, and 16S rRNA gene sequencing was used to assess the broader respiratory microbiome. TE sequencing identified Mh in 100% of TE-tested samples and classified multiple GSVs in all but 3 of 121 samples. GSV profiles clustered within housing groups and varied across cattle populations, indicating structured strain-level diversity. In contrast, Mannheimia spp. were detected in only 47.7% of samples by 16S rRNA sequencing. These findings demonstrate that TE sequencing enables sensitive, strain-level characterization of Mh in cattle and environmental samples and reveals substantial within-population genomic diversity not captured by conventional approaches.IMPORTANCETarget-enriched shotgun sequencing enabled sensitive, strain-level detection of Mannheimia haemolytica (Mh), revealing multiple co-circulating genomic sequence variants (GSVs) within and among cattle groups. This demonstrates greater genetic variability of Mh populations in beef cattle than has been previously recognized. The clustering of GSVs within housing groups, together with the overlap between respiratory and environmental samples, is consistent with the hypothesis that contagious transmission contributes to Mh ecology. These results highlight the potential utility of composite nasal swab and environmental samples for future studies evaluating relationships between Mh genomic variation and disease risk.

Animals↗

Significance of CpG methylation for solar UV-induced mutagenesis and carcinogenesis in skin.

Mutations detected in the p53 gene in human nonmelanoma skin cancers show a highly UV-specific mutation pattern, a dominance of C --> T base substitutions at dipyrimidine sites plus frequent CC --> TT tandem substitutions, indicating a major involvement of solar UV in the skin carcinogenesis. These mutations also have another important characteristic of frequent occurrences at CpG dinucleotide sites, some of which actually show prominent hotspots in the p53 gene. Although mammalian solar UV-induced mutation spectra were studied intensively in the aprt gene using rodent cultured cells and the UV-specific mutation pattern was confirmed, the second characteristic of the p53 mutations in human skin cancers had not been reproduced. However, studies with transgenic mouse systems developed thereafter for mutation research, which harbor methyl CpG-abundant transgenes as mutation markers, yielded complete reproductions of the situation of the human skin cancer mutations in terms of both the UV-specific pattern and the frequent occurrence at CpG sites. In this review, we evaluate the significance of the CpG methylation for solar UV mutagenesis in the mammalian genome, which would lead to skin carcinogenesis. We propose that the UV-specific mutations at methylated CpG sites, C --> T transitions at methyl CpG-associated dipyrimidine sites, are a solar UV-specific mutation signature, and have estimated the wavelength range effective for the solar-UV-specific mutation as 310-340 nm. We also recommend the use of methyl CpG-enriched sequences as mutational targets for studies on solar-UV genotoxicity for human, rather than conventional mammalian mutational marker genes such as the aprt and hprt genes.

Adenine Phosphoribosyltransferase↗

Evaluation of one-step amplicon-based targeted enrichment for SARS-CoV-2 whole-genome sequencing using the Midnight amplicon scheme.

Genomic surveillance proved invaluable during the COVID-19 pandemic for tracking SARS-CoV-2 variants and guiding outbreak responses, underscoring the ongoing need to reduce whole-genome sequencing (WGS) costs and improve workflow efficiency to ensure accessibility in resource limited settings. Here, we evaluated a one-step reverse transcription polymerase chain reaction (RT-PCR) approach using the Midnight V2 primer scheme for targeted amplification of the SARS-CoV-2 genome, assessed its compatibility with Illumina sequencing, and compared its performance to a well-established two-step method. Initially, we determined optimal RT-PCR reaction conditions using the Midnight V2 primer panel for the one-step RT-PCR kit and scaled reaction volumes for both RT-PCR and library preparation. Clinical specimens (n = 53) that had undergone routine WGS for surveillance purposes using the established two-step RT-PCR method were compared using the one-step RT-PCR assay. For samples with genome completeness greater than 70%, both methods gave comparable results with similar sequence coverage and 100% concordance for lineage assignment. Further investigation revealed a higher percentage of reads aligning to the SARS-CoV-2 genome with a greater depth of coverage using the one-step method compared to the two-step method. Finally, analysis of scaled one-step and library reaction volumes revealed significant cost savings for samples undergoing WGS. Overall, the results presented here verify the accuracy and reproducibility of one-step targeted amplification and offer an efficient and cost-effective workflow for routine SARS-CoV-2 genomic surveillance.

Humans↗

A target of the HoxB5 gene from the mouse nervous system.

An epitope-specific antibody against the protein product of the murine HoxB5 gene was used to select an enriched library of Hox target sequences. Genomic DNA was purified by immunoaffinity chromatography, using glutaraldehyde-cross-linked chromatin from CNS of mouse embryos at gestational day 15. Screening was done by colony hybridization with TAAT-containing oligonucleotides, filter DNA-protein binding, and gel mobility shift assay. Nucleotide sequencing identified a 910 bp DNA fragment, containing a consensus Antennapedia-like binding site, and identical in 640 bps at 3' end of the clone to the promoter of the SPI3 gene, which encodes a serine protease inhibitor protein [Sun, J., Rose, J.B. and Bird, P., J. Biol. Chem., 270 (1995) 16089-16096]. In situ hybridization experiments were performed to see if a correlation could be found between the expression patterns the SPI3 and the HoxB5 genes. Using a 120 bp cDNA fragment as probe, SPI3 expression was detected mainly in the CNS of 15 day mouse embryos, a pattern which is similar to that of the HoxB5 gene at this stage [Hogan, B.L., Holland, P.W. and Lumsden, A., Cell Diff. Dev., 25 Suppl. (1988) 39-44; Sakach, M. and Safaei, R., Int. J. Dev. Neurosci., 14 (1996) 567-573]. In conclusion, data presented here suggest that the SPI3 gene is a candidate target of the HoxB5 gene in vertebrate embryos.

Animals↗

Systematic identification of human mitochondrial disease genes through integrative genomics.

The majority of inherited mitochondrial disorders are due to mutations not in the mitochondrial genome (mtDNA) but rather in the nuclear genes encoding proteins targeted to this organelle. Elucidation of the molecular basis for these disorders is limited because only half of the estimated 1,500 mitochondrial proteins have been identified. To systematically expand this catalog, we experimentally and computationally generated eight genome-scale data sets, each designed to provide clues as to mitochondrial localization: targeting sequence prediction, protein domain enrichment, presence of cis-regulatory motifs, yeast homology, ancestry, tandem-mass spectrometry, coexpression and transcriptional induction during mitochondrial biogenesis. Through an integrated analysis we expand the collection to 1,080 genes, which includes 368 novel predictions with a 10% estimated false prediction rate. By combining this expanded inventory with genetic intervals linked to disease, we have identified candidate genes for eight mitochondrial disorders, leading to the discovery of mutations in MPV17 that result in hepatic mtDNA depletion syndrome. The integrative approach promises to better define the role of mitochondria in both rare and common human diseases.

Base Sequence↗

Screening for important base identities in the hairpin ribozyme by in vitro selection for cleavage.

Random mutagenesis followed by an in vitro selection procedure was shown to be capable of identifying important bases of the hairpin ribozyme for cleavage of an RNA target sequence. The selection scheme enriched the RNA population for those molecules capable of efficient site-specific self-cleavage in the absence of ligation. Cleavable mutants were selected for all positions in loop 4 except for position A38, supporting the notion that A38 is an important base in the hairpin ribozyme. This has been confirmed by direct mutagenesis, validating the utility of this procedure. Thus, the method developed and reported here has utility for the selection of efficient hairpin ribozymes capable of highly efficient cleavage of a substrate RNA without a requirement for ribozyme-catalyzed ligation, conditions desired for many applications of catalytic RNA such as gene therapy.

Base Composition↗