Base by Base

Gustavo Barra
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  • علوم حياة
  • يتم التحديث يوميًا

Base by Base explores advances in genetics and genomics, with a focus on gene-disease associations, variant interpretation, protein structure, and insights from exome and genome sequencing. Each episode breaks down key studies and their clinical relevance—one base at a time. Powered by AI, Base by Base offers a new way to learn on the go. Special thanks to authors who publish under CC BY 4.0, making open-access science faster to share and easier to explore.

  1. 289: MinION detection of chimeric reads in murine Ifna/Ifnb and Actb amplicons

    قبل يوم واحد

    289: MinION detection of chimeric reads in murine Ifna/Ifnb and Actb amplicons

    White R et al., F1000Research - Nanopore MinION sequencing of murine Ifna, Ifnb and Actb amplicons identified post-amplification chimeric reads during library ligation, with ~1.7% of mapped reads containing chimeric elements. Study Highlights: cDNA from a Nippostrongylus brasiliensis–treated mouse amplified for Ifna family, Ifnb and Actb amplicons. Key methods: separate PCR amplicons were barcoded, ligated using two methods (quick vs overnight), sequenced on an Oxford Nanopore MinION and base-called/mapped with Albacore and LAST. Main quantitative result: 4,563 reads (≈1.7% of amplicon/barcode-mappable 1D reads) were classified as definitively chimeric, with repeated identical amplicons most common and overnight ligation associated with more repeated-amplicon chimeras than quick ligation. Functional implication: post-amplification ligation during library prep can create detectable chimeric reads that long-read nanopore data and raw-signal inspection can identify and allow filtering, with implications for amplicon sequencing workflows and index switching concerns. Conclusion: Post-amplification ligation during library preparation produced detectable chimeric reads (~1.7%), and including identifiable adapters with careful long-read QC enables detection and exclusion of most chimeras. Music: Enjoy the music based on this article at the end of the episode. Reference: White R, Pellefigues C, Ronchese F, Lamiable O, Eccles D. Investigation of chimeric reads using the MinION [version 2; peer review: 2 approved]. F1000Research. 2017;6:631. https://doi.org/10.12688/f1000research.11547.2 License: This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) - https://creativecommons.org/licenses/by/4.0/ Support: Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00 Official website https://basebybase.com On PaperCast Base by Base you’ll discover the latest in genomics, functional genomics, structural genomics, and proteomics. Episode link: https://basebybase.castos.com/episodes/minion-chimeric-reads-ligation-ifna

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  2. قبل يومين

    288: Cryo-EM of rat cerebellar α1/α6 GABAA receptors reveals PZ‑II‑029 binding and β-α-β-α-γ assemblies

    Sun C et al., PNAS - Using cryo-EM and mass spectrometry in rat cerebellum, α1- and α6-containing GABAA receptor assemblies (β‑α‑β‑α‑γ stoichiometry) and PZ-II-029 binding were defined. Study Highlights: The study used rat cerebellum tissue and combined confocal immunofluorescence, affinity purification with mass spectrometry, and high-resolution cryo-EM to characterize native α1-containing GABAA receptors. Cryo-EM classification resolved eight distinct α1-containing receptor assemblies that conform to a conserved β-α-β-α-γ arrangement and include previously unreported α6-containing heteromers. Structural models of α6-containing receptors show near-symmetric ECD architecture with conserved GABA-binding geometry and distinct electrostatic differences that may affect ligand kinetics. Binding of the α6-selective pyrazoloquinolinone PZ-II-029 at α+/γ− pockets was visualized and found to induce coordinated outward expansion of the extracellular domain, providing a structural basis for subtype-selective modulation. Conclusion: Native α1-containing cerebellar GABAA receptors adopt a conserved β-α-β-α-γ pentameric scaffold that includes α6 subunits and binds PZ-II-029 at α+/γ− sites, producing extracellular domain expansion. Music: Enjoy the music based on this article at the end of the episode. Reference: Sun C, Jahncke JN, Wright KM, Gouaux E. Molecular assemblies and pharmacology of cerebellar GABAA receptors. Proc. Natl. Acad. Sci. U.S.A. 2026;123:e2524504123. Published February 6, 2026. https://doi.org/10.1073/pnas.2524504123 License: This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) - https://creativecommons.org/licenses/by/4.0/ Support: Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00 Official website https://basebybase.com On PaperCast Base by Base you’ll discover the latest in genomics, functional genomics, structural genomics, and proteomics. Episode link: https://basebybase.castos.com/episodes/cerebellar-gabaa-alpha6-assemblies

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  3. قبل ٣ أيام

    287: EPOP and MTF2 modulate PRC2 H3K27me3 deposition via GA- and GCN-sequence specificity

    Granata J et al., PNAS - In mESCs and defined in vitro assays, EPOP and MTF2 stimulate PRC2 methyltransferase activity and promote de novo H3K27me3 deposition with GA- or GCN-rich DNA preference. Study Highlights: The study used mouse embryonic stem cells with an EED-rescue system and recombinant in vitro assays including HMT assays, EMSA, and ChIP-seq to probe EPOP and MTF2 function. Biochemical HMT assays on oligonucleosomes and dinucleosomes show both EPOP and MTF2 directly stimulate PRC2 catalytic activity, with MTF2 preferentially enhancing activity and binding on GCN-rich linkers and EPOP on GA-rich linkers. ChIP-seq during EED rescue demonstrated that EPOP is dispensable for initial PRC2 recruitment but its knockout reduces de novo H3K27me3 deposition by ~50% and cooperates with MTF2 and JARID2. Together these data indicate linker DNA sequence within nucleation sites guides subcomplex-specific PRC2 binding and catalytic output, influencing spatial establishment of H3K27me3 domains. Conclusion: EPOP and MTF2 define distinct PRC2 subcomplexes that stimulate PRC2 catalytic activity in a chromatin-dependent, DNA-sequence-specific manner to direct de novo H3K27me3 deposition. Music: Enjoy the music based on this article at the end of the episode. Reference: Granata J., Liu S., Popoca L., Oksuz O., Reinberg D. EPOP and MTF2 activate PRC2 activity through DNA-sequence specificity. Proc. Natl. Acad. Sci. U.S.A. 2026;123:e2527303123. https://doi.org/10.1073/pnas.2527303123 License: This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) - https://creativecommons.org/licenses/by/4.0/ Support: Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00 Official website https://basebybase.com On PaperCast Base by Base you’ll discover the latest in genomics, functional genomics, structural genomics, and proteomics. Episode link: https://basebybase.castos.com/episodes/epop-mtf2-prc2-sequence

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  4. قبل ٤ أيام

    286: Deep mutational scanning of Nipah virus fusion protein F reveals functional and antigenic constraints

    Larsen BB et al., PNAS - Deep mutational scanning of the Nipah virus fusion protein F using pseudoviruses maps ~8,500 single-residue effects, showing F is highly constrained and identifying antibody-escape mutations. Study Highlights: Using nonreplicative lentiviral pseudoviruses and deep mutational scanning, the authors measured the effects of 8,449 single amino-acid mutations to the Nipah virus F ectodomain on cell entry in CHO cells expressing bat ephrin-B3. Measurements were fit with global epistasis models and mapped onto prefusion and postfusion structures, revealing the fusion peptide, lateral surface patches, and hexameric-interface residues are highly constrained. The library was screened against six monoclonal antibodies, quantifying mutation-mediated decreases in neutralization and showing distinct resilience among antibodies; specific Hendra F residues (Q70K, R336K) explained loss or reduction of neutralization by 4H3 and 1A9. The data nominate candidate proline substitutions and other sites for prefusion stabilization and inform vaccine and therapeutic antibody selection. Conclusion: Nipah virus F is highly functionally constrained relative to RBP with specific surface-exposed and core residues critical for cell entry, and antibody neutralization varies by epitope, informing prefusion-stabilized immunogen and therapeutic antibody design. Music: Enjoy the music based on this article at the end of the episode. Reference: Larsen BB, Harari S, Gen R, Stewart C, Veesler D, Bloom JD. Functional and antigenic constraints on the Nipah virus fusion protein. Proc. Natl. Acad. Sci. U.S.A. 2026;123:e2529505123. https://doi.org/10.1073/pnas.2529505123 License: This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) - https://creativecommons.org/licenses/by/4.0/ Support: Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00 Official website https://basebybase.com On PaperCast Base by Base you’ll discover the latest in genomics, functional genomics, structural genomics, and proteomics. Episode link: https://basebybase.castos.com/episodes/nipah-f-deep-mutational-map

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  5. قبل ٥ أيام

    285: ESBX (Tb927.3.1660) integrates ESB RNA Pol I localization with BES activation and VSG repression in Trypanosoma brucei

    Berazategui MA et al., PNAS - ESBX (Tb927.3.1660) links RNA Pol I localization at the ESB to activation of the active BES and repression of inactive BESs in Trypanosoma brucei, supporting monoallelic VSG expression. Study Highlights: Using ESB1-guided proximity-dependent biotinylation proteomics, endogenous tagging and high-resolution fluorescence microscopy, RNAi knockdown, RNA-seq, and inducible overexpression in bloodstream-form Trypanosoma brucei, the authors identify Tb927.3.1660 (ESBX) as an ESB-specific protein. ESBX localizes adjacent to Pol I (RPA2) and ESB1 within the ESB with measured center separations of ~68–175 nm and contains predicted SUMO-interacting and BRCT domains. ESBX depletion causes loss of the extranucleolar Pol I ESB focus, reduced processive transcription from the active BES with larger decreases distal to the promoter, and derepression of inactive BESs with low-processivity transcripts, whereas ESBX overexpression weakly activates inactive BESs with processive transcription without forming extra ESBs. Together the data indicate ESBX integrates activation of the active BES with repression of inactive BESs, a mechanism that supports monoallelic VSG expression. Conclusion: Tb927.3.1660/ESBX is an ESB component required to integrate activation of the active BES with repression of inactive BESs, thereby supporting monoallelic VSG expression in bloodstream-form Trypanosoma brucei. Music: Enjoy the music based on this article at the end of the episode. Reference: Berazategui MA, Wheeler RJ, Tiengwe C, Lansink LIM, Rudenko G, Sunter JD, Goodwin I, Gull K, Faria JRC, et al. A factor integrating transcription and repression of surface antigen genes in African trypanosomes. Proc. Natl. Acad. Sci. U.S.A. 2026.123:e2531377123. https://doi.org/10.1073/pnas.2531377123 License: This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) - https://creativecommons.org/licenses/by/4.0/ Support: Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00 Official website https://basebybase.com On PaperCast Base by Base you’ll discover the latest in genomics, functional genomics, structural genomics, and proteomics. Episode link: https://basebybase.castos.com/episodes/esbx-esb-vsg-regulation

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  6. قبل ٦ أيام

    284: FES, VSMC behavior and pleiotropic vascular genes identified by integrative functional genomics

    Solomon CU et al., Nat Commun ( - Integrative analysis in human VSMCs identifies pleiotropic genes including FES that regulate vascular remodeling; pooled CRISPR and mouse knockout show FES loss increases MMPs, atherosclerosis and blood pressure. Study Highlights: The study used a large human umbilical cord‑derived VSMC eQTL bank (n=1,486) combined with colocalization (eCAVIAR, SMR/HEIDI), ATAC‑seq, DNA methylation, H3K27ac HiChIP and pooled CRISPR‑Cas9 knockout screens to nominate likely causal genes for CAD, hypertension, stroke and AAA. Pooled CRISPR screens and siRNA validation in VSMCs highlighted BCAR1, CARF, SMARCA4 and FES as modulators of VSMC proliferation or migration, while FES knockdown increased MMP1/MMP3, reduced contractile markers and promoted migration by RNA‑seq and proteomics/phosphoproteomics. In vivo, Fes‑/-/Apoe‑/- mice had larger en face aortic lesion areas (8.34±2.54% vs 6.06±2.35%, P=0.013) and higher baseline systolic/diastolic blood pressure (104.4±6.7 vs 88.0±10.1 mmHg and 74.9±9.0 vs 58.8±8.9 mmHg, P=0.042). These results support FES as a pleiotropic, potentially druggable regulator of VSMC phenotype with functional effects on atherosclerosis and blood pressure. Conclusion: Integrative functional genomics implicates panels of likely causal and pleiotropic genes, including FES, that regulate VSMC behavior and whose loss promotes VSMC dedifferentiation, increased MMP production, larger atherosclerotic lesions and higher blood pressure. Music: Enjoy the music based on this article at the end of the episode. Reference: Solomon CU, McVey DG, Andreadi C, Peng G, Turner L, Song DSS, Zhang H, Lee DP, Karamanavi E, Yang W, Chu J, Chen R, Haworth KE, Anene-Nzelu CG, Li H, Denniff MJ, Li PY, Zhang Y, Huang X, Morris GE, Greer PA, Stringer EJ, Yu H, Foo RSY, Douglas G, Samani NJ, Webb TR, Ye S. Integrative functional genomics analysis identifies pleiotropic genes for vascular diseases. Nat Commun (2026). https://doi.org/10.1038/s41467-026-69273-8 License: This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) - https://creativecommons.org/licenses/by/4.0/ Support: Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00 Official website https://basebybase.com On PaperCast Base by Base you’ll discover the latest in genomics, functional genomics, structural genomics, and proteomics. Episode link: https://basebybase.castos.com/episodes/fes-vsmc-pleiotropic-genes

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  7. ٧ فبراير

    283: Confidence in genetic knowledge drives Familiarity, Knowledge, and Skills in US GALS samples

    Ramírez Renta GM et al., The American Journal of Human Genetics - GALS survey of >4,000 US respondents (GenPop and SPARK) shows confidence in genetic knowledge predicts Familiarity, Knowledge, and Skills, explaining ~25% of variance. Study Highlights: Using the Genetic and Autism Literacy Survey (GALS) in two US samples (GenPop and SPARK; n>4,000), the authors measured three genetic literacy components: Familiarity, Knowledge, and Skills via subjective familiarity ratings, objective true/false items, and a comprehension task. They modeled associations between these subscales and identity/belief measures including perceived importance, confidence, religiosity, religious affiliation, and political belief using linear regression adjusted for education and population. Confidence in one’s genetic knowledge was the strongest predictor, accounting for roughly 25% of variance in Familiarity and Knowledge and substantially improving model R2; perceived importance had a positive but smaller effect while religious and political measures showed mixed associations. The finding implies improving individuals’ confidence in genetic knowledge, alongside tailored communication strategies, could support better comprehension and uptake of genetics and genomics services. Conclusion: Confidence in one’s genetic knowledge, after education, is the largest modifiable predictor of genetic literacy and should be a focus for interventions to improve comprehension and uptake of genetics services. Music: Enjoy the music based on this article at the end of the episode. Reference: Ramírez Renta GM, Little ID, Koehly LM, et al. Interaction of identity and beliefs with genetic literacy. The American Journal of Human Genetics. 2026;113:16–28. https://doi.org/10.1016/j.ajhg.2025.11.014 License: This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) - https://creativecommons.org/licenses/by/4.0/ Support: Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00 Official website https://basebybase.com On PaperCast Base by Base you’ll discover the latest in genomics, functional genomics, structural genomics, and proteomics. Episode link: https://basebybase.com/?episode=283-confidence-in-genetic-knowledge-drives-familiarity-knowl-17ljvj2

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  8. ٦ فبراير

    282: Gene-specific variance-control corrects polygenicity-driven inflation in TWAS

    Liang Y et al., The American Journal of Human Genetics. 113 ( - TWAS using genetically predicted expression exhibit polygenicity-driven inflation that increases with GWAS sample size and heritability; a gene-specific variance-control correction yields calibrated p values. Study Highlights: The authors evaluated TWAS and related xWAS using simulated polygenic null traits and UK Biobank genotypes with predicted mediators including gene expression, metabolites, and brain features. They combined large-scale simulations, theoretical derivations, and empirical regression of mean Z2 on N*h2δ to estimate a gene-specific inflation slope Φ and applied corrections with S‑PrediXcan/PrediXcan across 110 GWAS traits. They show analytically and empirically that Var(Z) ≈ 1 + N*h2δ*Φ, observe a cohort-level slope around 4.2×10^-5, and demonstrate that dividing Z by sqrt(1+N*h2δ*Φ) restores calibration. Applying the variance-control correction yields well-calibrated p values, reduces false positives for highly polygenic traits, and improves precision with minimal loss of power. Conclusion: A gene-specific variance-control correction based on an empirically estimated inflation slope Φ corrects polygenicity-driven inflation in TWAS/xWAS and yields calibrated false-positive rates in simulations and real GWAS analyses. Music: Enjoy the music based on this article at the end of the episode. Reference: Liang Y, Nyasimi F, Im HK. A gene-specific variance-control approach corrects polygenicity-driven inflation observed in transcriptome-wide association studies. The American Journal of Human Genetics. 113 (2026) 276-290. https://doi.org/10.1016/j.ajhg.2025.12.014 License: This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) - https://creativecommons.org/licenses/by/4.0/ Support: Base by Base – Stripe donations: https://donate.stripe.com/7sY4gz71B2sN3RWac5gEg00 Official website https://basebybase.com On PaperCast Base by Base you’ll discover the latest in genomics, functional genomics, structural genomics, and proteomics. Episode link: https://basebybase.castos.com/episodes/twas-variance-control-inflation

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Base by Base explores advances in genetics and genomics, with a focus on gene-disease associations, variant interpretation, protein structure, and insights from exome and genome sequencing. Each episode breaks down key studies and their clinical relevance—one base at a time. Powered by AI, Base by Base offers a new way to learn on the go. Special thanks to authors who publish under CC BY 4.0, making open-access science faster to share and easier to explore.

المعلومات

  • صناع العمل
    Gustavo Barra
  • سنوات النشاط
    ٢٠٢٥ - ٢٠٢٦
  • الحلقات
    ٢٨٩
  • التقييم
    ملائم
  • حقوق النشر
    © Gustavo Barra
  • موقع البرنامج على الويب
    Base by Base