342: Modular MPRA Reveals Context-Dependent Regulation at T2D Loci

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/

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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...