Hou P et al., PNAS - This study combines kinetic assays and X‑ray crystallography to show how 8‑oxo‑guanosine triphosphate (8‑oxo‑rGTP) is incorporated by RNA polymerase II and how its pairing geometry with template bases (dC vs dA) differentially alters incorporation efficiency, extension, and proofreading, thereby introducing transcription‑coupled RNA damage. Key terms: RNA damage, 8-oxo-rGTP, RNA polymerase II, transcription fidelity, oxidative stress.

Study Highlights:
Pol II incorporates 8‑oxo‑rGTP efficiently opposite dC with kinetics comparable to GTP, whereas incorporation opposite dA is much slower but ~150‑fold more efficient than misincorporation of undamaged rGTP. Extension proceeds rapidly from a 3′‑r8OG:dC pair but is markedly slower from a 3′‑r8OG:dA pair. TFIIS‑stimulated proofreading cleaves r8OG:dC robustly but r8OG:dA is resistant to backtracking and cleavage. Crystal structures reveal 8‑oxo‑rG adopts anti Watson–Crick geometry with dC in the A‑site but flips to syn Hoogsteen geometry with dA, where an interaction with Rpb2 E529 stabilizes a pretranslocation state.

Conclusion:
Oxidation of the nucleotide pool can directly undermine Pol II fidelity by enabling efficient incorporation and differential handling of 8‑oxo‑rGTP, producing transcription‑coupled RNA damage with potential consequences for RNA processing, translation, and disease.

Music:
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Article title:
Structural basis of transcription -coupled RNA damage by incorporation of oxidized ribonucleotides

First author:
Hou P

Journal:
PNAS

DOI:
10.1073/pnas.2602266123

Reference:
Hou P, Lee C, Chong J, Oh J, Wang D. Structural basis of transcription-coupled RNA damage by incorporation of oxidized ribonucleotides. PNAS. 2026;123(16):e2602266123. doi:10.1073/pnas.2602266123

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/episodes/8oxo-rgpt-transcription-rna-damage

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-04-24.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited sections on background, kinetic experiments, structural determinations, proofreading, translocation mechanics, and disease relevance; aligned with the canonical article.
- transcript topics: Oxidative stress and oxidized ribonucleotides; 8-oxo-rGTP incorporation opposite dC and dA templates; Presteady-state kinetics and incorporation efficiency; Extension after 8-oxo-rGTP incorporation; TFIIS proofreading and backtracking with oxidized nucleotides; Structural basis: A-site anti conformation with dC; syn Hoogsteen with dA; E529 fork loop 2 interaction

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 8
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- 8-oxo-rGTP can be efficiently incorporated opposite dC, with efficiency comparable to GTP
- 8-oxo-rGTP opposite dA is misincorporated ~150-fold more efficiently than rGTP misincorporation
- Pol II extends more efficiently from 8-oxo-rG:d...

Wang Y et al et al., PNAS - This episode covers a PNAS study describing v96, a personalized plasma cell-free DNA assay that tracks up to 96 patient-specific mutations to sensitively quantify measurable residual disease (MRD) in AML patients before and after allogeneic hematopoietic cell transplantation. Key terms: cell-free DNA, measurable residual disease, acute myeloid leukemia, hematopoietic cell transplantation, duplex sequencing.

Study Highlights:
The personalized v96 assay detected residual leukemia in 100% of 30 AML patients at clinical remission, compared with 20% by flow cytometry. Plasma cfDNA was more informative and sensitive than bone marrow DNA and driver mutation assays, with 90% of patients positive at 2 months posttransplant. Higher pretransplant mutant molecule counts correlated with relapse risk, and leukemic burden typically fell only after immunosuppression was discontinued, consistent with a graft-versus-leukemia effect.

Conclusion:
A plasma-based multiplexed assay (v96) enables highly sensitive, noninvasive MRD monitoring in AML patients undergoing transplantation and may inform timing of immunosuppression and posttransplant interventions, though larger studies are needed to confirm clinical utility.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
A plasma - based DNA test for quantification of disease burden in acute myeloid leukemia patients undergoing bone marrow transplantation

First author:
Wang Y et al

Journal:
PNAS

DOI:
10.1073/pnas.2537987123

Reference:
Wang Y et al., A plasma-based DNA test for quantification of disease burden in acute myeloid leukemia patients undergoing bone marrow transplantation. PNAS. 2026;123(16):e2537987123. doi:10.1073/pnas.2537987123

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/episodes/v96-plasma-ctdna-aml-transplant

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-04-21.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the transcript’s presentation of the v96 methodology, passenger vs driver mutations, plasma vs marrow MRD detection, relapse prediction, and posttransplant immunosuppression dynamics against the original article.
- transcript topics: v96 workflow and passenger mutation panel; duplex sequencing (SaferSeqS) and error suppression; plasma vs bone marrow cell-free DNA for MRD detection; driver vs passenger mutations for MRD assessment; predictive power for relapse (352-fold difference pre-transplant); graft-versus-leukemia (GvL) dynamics and immunosuppression

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 5
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- v96 assay tracks up to 96 leukemia-specific passenger mutations in plasma cfDNA and detects residual leukemia in all patients at complete remission (CR) by v96, vs 20% by flow cyto
- plasma cfDNA mutant-allele fractions (MAF) are higher than bone marrow DNA (2.9% vs 0.42%) at CR
- pre-transplant plasma mutant m...

• (00:00:09) - How to Catch a Leukemia Patient's Disease in the Dark
• (00:06:43) - The 96-Point mutation detection
• (00:11:15) - Blood tests for leukemia no longer find cancer
• (00:14:04) - Can V96 Predict Who Will Get Sick?
• (00:20:53) - 96 Names in the Line

Holta KB et al., Proceedings of the National Academy of Sciences (PNAS) - This episode explains a quantitative framework for diffusion on spatially embedded dynamic mitochondrial networks. The study combines analytic theory, agent-based simulations, and live-cell imaging to show how connectivity, fusion/fission, and mobility set biomolecular mixing on mitochondrial populations. Key terms: mitochondria, diffusion, intracellular transport, temporal networks, fusion-fission.

Study Highlights:
The authors develop an analytic and simulation framework for diffusive spreading on spatially embedded dynamic networks formed by mitochondrial fusion and fission. They identify a connectivity-driven transition from three-dimensional dispersion across transiently interacting clusters (social regime) to low-dimensional transport along largely stationary interconnected tubules (physical regime). The steady-state distribution is determined by competing timescales for cluster filling, encounter, fusion/fission, and material decay. Application to three human cell lines reveals cell-type variability in predicted spreading times, with hyperfused networks limited by intracluster diffusion and fragmented networks limited by encounters.

Conclusion:
Network connectivity and the balance of diffusion, encounter, and fusion/fission timescales quantitatively determine mitochondrial material homogenization, producing distinct scaling regimes with measurable predictions across cell types.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Diffusive spreading across dynamic mitochondrial network architectures

First author:
Holta KB

Journal:
Proceedings of the National Academy of Sciences (PNAS)

DOI:
10.1073/pnas.2523913123

Reference:
Holta KB, Zurita C, Teryoshin L, Lewis SC, Koslover EF. Diffusive spreading across dynamic mitochondrial network architectures. Proc Natl Acad Sci U S A. 2026;123(15):e2523913123. doi:10.1073/pnas.2523913123

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/episodes/diffusive-spreading-mitochondrial-networks

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-04-19.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Substantive auditing of the transcript’s representation of the article’s core framework, regimes, timescales, cell-type predictions, modeling approach, and acknowledged limitations, with cross-checks against the original article text and the facts pack.
- transcript topics: Temporal networks framework for diffusion on dynamic mitochondrial networks; Physical vs social mitochondrial network regimes; Four timescales governing diffusion: decay, cluster filling, encounter, fission; Agent-based spherocylindrical model and finite-volume diffusion; Time-resolved imaging and cell-type parameterization (SH-SY5Y, IMR90, U2OS); Predictions of spreading times across cell types

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 7
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audite...

Kimchi O et al., PNAS - This computational study shows that self-complementary RNA regions (palindromes) can drive sequence-specific homotypic clustering by enabling multivalent intermolecular base pairing, and that Drosophila nanos and pgc mRNAs are enriched for accessible, strong palindromes. Key terms: RNA palindromes, homotypic clustering, germ granules, nanos mRNA, phase separation.

Study Highlights:
The authors use equilibrium and nonequilibrium in silico analyses to show palindromic regions increase the likelihood of homodimer and higher-order homomultimer formation. Palindrome binding strength correlates with multimerization propensity, and accessible strong palindromes are enriched in nanos and pgc compared to length-matched Drosophila mRNAs. Out-of-equilibrium calculations indicate initial accessible palindromic interactions can favor homotypic binding despite general heterodimer preference. The framework suggests palindromes could be under evolutionary selection and predicts experimental tests using designed synthetic sequences.

Conclusion:
Palindromic, self-complementary RNA regions provide a generic mechanism for RNA self-recognition and can explain homotypic clustering in germ granules; palindrome content may be under evolutionary selection and can guide experimental tests with synthetic RNAs.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
How do RNA molecules distinguish self from non-self?

First author:
Kimchi O

Journal:
PNAS

DOI:
10.1073/pnas.2603593123

Reference:
Kimchi O, Mitchel K, Pyod AGT, Wingreen NS, Gavis ER. How do RNA molecules distinguish self from non-self? PNAS. 2026;123(15):e2603593123. doi:10.1073/pnas.2603593123

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/episodes/palindromes-rna-self-recognition

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-04-19.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the transcript portions describing palindromic self-recognition, equilibrium and nonequilibrium modeling, nanos/pgc enrichment, cross-species considerations, GFP tail experiment, evolutionary implications, clinical and synthetic biology implications, and study limitations.
- transcript topics: Palindromic regions as self-recognition mechanism; Equilibrium vs nonequilibrium RNA interactions; Nanos and pgc palindromes: binding strength and accessibility; GFP tail experiment and cross-context clustering; Evolutionary selection and clinical implications; Limitations of in silico modeling and need for in vitro validation

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 8
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- Palindromic regions enable self-recognition and drive homotypic clustering via multivalent RNA–RNA interactions
- Nanos and pgc RNAs are enriched for accessible, strongly binding palindromes and cluster with their own type
- Out-of-equilibrium modeling shows nanos and pgc have higher homodimer...

Scartozzi AC et al., Human Genetics and Genomics Advances - This episode reviews a GWAS of speech rhythm (prosody) perception using the TOPsy task (n≈1,501 European-ancestry), reporting 14 suggestive loci, nominal enrichment for songbird vocal-learning gene sets, and polygenic links to reading and musical rhythm. Key terms: prosody, speech rhythm, genetics, musical rhythm, reading.

Study Highlights:
The authors performed a GWAS of TOPsy speech rhythm scores in ~1,501 individuals of European genetic ancestry and identified 14 loci reaching suggestive significance but no genome-wide significant hits. Gene-based analyses flagged TTLL1 and GP2 among the top genes without Bonferroni significance. Gene-set enrichment showed nominal overlap with songbird Area X vocal-learning gene sets, consistent with evolutionary convergence hypotheses. Polygenic score analyses demonstrated shared genetic influences between prosody perception and both word reading and beat synchronization, while voice-pitch PGS results were weaker.

Conclusion:
Findings provide initial genomic evidence that prosody perception is polygenic and shares genetic architecture with reading and musical rhythm, and they motivate larger, more diverse samples and scalable phenotyping (TOPsy) to validate and extend these results.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Genome-wide investigation of prosody perception: Shared genetic influences between speech rhythm, musical rhythm, and reading traits

First author:
Scartozzi AC

Journal:
Human Genetics and Genomics Advances

DOI:
10.1016/j.xhgg.2026.100581

Reference:
Scartozzi AC, Wang Y, Coleman PL, et al. Genome-wide investigation of prosody perception: Shared genetic influences between speech rhythm, musical rhythm, and reading traits. Human Genetics and Genomics Advances. 2026;7:100581. https://doi.org/10.1016/j.xhgg.2026.100581

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/episodes/genes-of-prosody-rhythm-music-reading

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-04-17.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the transcript sections describing: the definition/importance of prosody and speech rhythm; TOPsy test methodology; GWAS results (no genome-wide hits, 14 suggestive loci); top gene signals (TTLL1 and GP2); cross-species birdsong gene-set enrichment (Area X); polygenic score analyses (word reading, beat synchron
- transcript topics: Definition and importance of prosody and speech rhythm; TOPsy remote 28-item test design and phenotyping; Genome-wide association results for TOPsy (n=1501 European ancestry); Gene-based GWAS signals TTLL1 and GP2; Birdsong gene-set enrichment: Area X and cross-species convergence; Polygenic score analyses: word reading and beat synchronization predicting TOPsy

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 5
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- TOPsy is a 28-item remote, auto...

Kühnisch J et al., Human Genetics and Genomics Advances 7, 100598 (2026) - Case report and tissue analysis linking a homozygous TNNI3 nonsense variant (c.406C>T; p.Arg136*) to early-onset, treatment-refractory restrictive cardiomyopathy in a young child who required heart transplantation. Key terms: TNNI3, restrictive cardiomyopathy, pediatric cardiomyopathy, troponin I, protein truncation.

Study Highlights:
A 2-year-old female with severe pediatric restrictive cardiomyopathy carried a homozygous TNNI3 c.406C>T (p.Arg136*) nonsense variant. Myocardial immunostaining showed approximately 50% reduced TNNI3 protein abundance though truncated protein remained detectable. Electron microscopy revealed myofibrillar disarray, irregular Z bands, indistinct M lines, and mitochondrial hyperplasia. The clinical course was treatment refractory and led to heart transplant at 28 months, implicating variant zygosity and truncation position in phenotype determination.

Conclusion:
Biallelic truncation of TNNI3 (p.Arg136*) can cause severe early-onset pediatric restrictive cardiomyopathy, with reduced but partially stable truncated protein and severe sarcomeric pathology prompting early transplantation.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
A homozygous variant in cardiac troponin I3, TNNI3, causes severe pediatric restrictive cardiomyopathy

First author:
Kühnisch J

Journal:
Human Genetics and Genomics Advances 7, 100598 (2026)

DOI:
10.1016/j.xhgg.2026.100598

Reference:
Kühnisch J, Barnett CL, Brendel J, et al. A homozygous variant in cardiac troponin I3, TNNI3, causes severe pediatric restrictive cardiomyopathy. Human Genetics and Genomics Advances. 7:100598. https://doi.org/10.1016/j.xhgg.2026.100598

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/episodes/tnni3-arg136-pediatric-rcm

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-04-17.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the transcript's representation of the genetic case, protein expression, tissue analyses, mechanistic interpretation, and genotype–phenotype implications as described in the article.
- transcript topics: RCM vs DCM distinctions; TNNI3 function in the troponin complex; Case presentation and homozygous TNNI3 variant; DNA sequencing and parental segregation; Protein expression by immunostaining; Ultrastructural TEM findings

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 6
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- Homozygous TNNI3 nonsense variant c.406C>T (p.Arg136*) identified in the proband.
- Proband presented with severe restrictive cardiomyopathy (RCM) requiring heart transplantation at 28 months.
- TNNI3 protein abundance was reduced by approximately 50%, with detectable truncated protein remaining.
- TEM showed sarcomeric disarray and mitochondrial hyperplasia in explanted heart tissue.
- NMD failed to completely eliminate the tr...

López-Astacio RA et al., PNAS - Analysis of 60 years of feline panleukopenia virus genomes traces the origins of canine parvovirus, identifies vaccine-derived sequences, and documents distinct evolutionary rates and capsid adaptations that enabled a host jump to dogs. Key terms: parvovirus, FPV, CPV, host jump, evolution.

Study Highlights:
Using full-genome sequencing and phylogenetics, the authors compare 60 years of FPV evolution with 47 years of CPV evolution and identify vaccine-derived sequences that cluster with early isolates. FPV evolves at roughly one-third the rate of CPV in dogs, while the CPV ancestor is closely related to European FPV-like strains and carries multiple capsid mutations linked to binding the canine transferrin receptor. Live-attenuated FPV vaccines derive from early 1960s isolates and FPV shows little antigenic selection compared to the faster-evolving CPV lineage. These patterns emphasize distinct evolutionary dynamics in reservoir versus new hosts during epidemic emergence.

Conclusion:
A single FPV-related lineage from Europe accumulated multiple capsid changes enabling canine TfR binding and gave rise to the CPV pandemic; thereafter CPV evolved approximately 3–4 times faster in dogs, while FPV in its reservoir hosts showed slow evolution with limited antigenic change and persistent vaccine-derived genomes in databases.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Distinct evolutionary patterns of endemic and emerging parvoviruses and the origin of a new pandemic virus

First author:
López-Astacio RA

Journal:
PNAS

DOI:
10.1073/pnas.2515274123

Reference:
López-Astacio RA, Wasik BR, Lee H, Voorhees IEH, Weichert WS, Adu OF, Goodman LB, Hafenstein SL, Truyen U, Parrish CR. Distinct evolutionary patterns of endemic and emerging parvoviruses and the origin of a new pandemic virus. PNAS. 2026;123(16):e2515274123. doi:10.1073/pnas.2515274123

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/episodes/feline-to-canine-parvovirus-origins

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-04-15.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the transcript sections describing FPV reservoir, CPV emergence, TfR binding and glycosylation barriers, VP2/other capsid mutations, evolutionary rates, vaccine-derived FPV sequences, antigenic variation, intermediate hosts, and missing ancestral link.
- transcript topics: FPV feline reservoir and CPV emergence; Transferrin receptor binding and canine TfR glycosylation barrier; VP2 mutations and host-range adaptation; Evolutionary rates FPV vs CPV and molecular clock methods; Vaccine-derived FPV sequences and vaccine filtering; Antigenic variation in FPV vs CPV and vaccine efficacy

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 6
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- CPV originated from European FPV lineage with host-range mutations enabling canine TfR binding
- CPV subst...

Tovar A et al., Human Genetics and Genomics Advances - This episode examines a study that used a modular MPRA to test ~11,656 genomic fragments from T2D- and metabolic trait-associated regions in pancreatic beta cells, comparing upstream vs downstream positions and SCP1 vs INS promoters. The work identifies promoter- and position-dependent regulatory activity and implicates HNF1 motifs in INS promoter-specific effects. Key terms: massively parallel reporter assay, type 2 diabetes, noncoding regulation, HNF1, promoter-enhancer compatibility.

Study Highlights:
The authors screened nearly 12,000 fragments across T2D- and metabolic trait-associated regions in a pancreatic beta cell model using four MPRA configurations (up/down × SCP1/INS). They found ~6% of fragments show significant promoter bias and ~6% show position bias, with INS-preferring fragments enriched for HNF1 motifs. Targeted motif perturbation MPRA showed HNF1 motif disruption reduced activity specifically in the INS promoter context and in beta cells but not in skeletal muscle, indicating cell-type and promoter-specific regulatory dependencies. The results highlight that MPRA construct design choices materially affect detection and interpretation of regulatory activity.

Conclusion:
Promoter identity and fragment position influence MPRA-detected regulatory activity, and tissue-specific promoters (like INS) can reveal TF-dependent regulatory mechanisms (e.g., HNF1) at T2D-linked noncoding regions.

Music:
Enjoy the music based on this article at the end of the episode.

Article title:
Using a modular massively parallel reporter assay to discover context-dependent regulatory activity in type 2 diabetes-linked noncoding regions

First author:
Tovar A

Journal:
Human Genetics and Genomics Advances

DOI:
10.1016/j.xhgg.2026.100606

Reference:
Tovar A, Kyono Y, Nishino K, Bose M, Varshney A, Parker SCJ, Kitzman JO. Using a modular massively parallel reporter assay to discover context-dependent regulatory activity in type 2 diabetes-linked noncoding regions. Human Genetics and Genomics Advances (2026). doi: https://doi.org/10.1016/j.xhgg.2026.100606

License:
http://creativecommons.org/licenses/by-nc-nd/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/episodes/modular-mpra-t2d-context-dependent-regulation

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-04-14.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the scientific content describing MPRA design parameters, library size, cell models, promoter/position bias findings, HNF1 motif associations and perturbations, and cross-tissue results as presented in the transcript.
- transcript topics: MPRA design configurations (promoter: INS vs SCP1; position: upstream vs downstream); Library scale and construction (11,656 fragments; ~13,226 sites; 198-bp fragments with adapters); Cell models used (832/13 rat beta-cell line; LHCN-M2 human skeletal muscle cells); Promoter bias findings (INS promoter bias ~73.4%; 698 fragments promoter-biased); Position bias findings (703 fragments showing upstream/downstream bias); Motif enrichment and HNF1A/B associations with INS promoter activity

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 7
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- arti...