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Updated: Sep 8, 2025
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Author Spotlight: Advancements in Cultivating Mouse Hair Cells for Auditory Research
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Differential Chromatin Accessibility, Gene Expression, and mRNA Splicing Between Developing Cochlear Inner and Outer
Chuan Zhi Foo1,2, Anne Duggan1, Elizabeth T Bartom3
1Department of Anesthesiology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA.
Journal of the Association for Research in Otolaryngology : JARO
|September 5, 2025
Summary
Developing inner and outer hair cells in the cochlea show distinct gene expression and splicing patterns, regulated by chromatin accessibility. This research offers insights into the molecular basis of hearing and deafness.
Area of Science:
- Genomics
- Epigenetics
- Developmental Biology
Background:
- Mammalian cochlear hair cells, inner (IHC) and outer (OHC), are crucial for hearing.
- Dysfunction or loss of these cells leads to congenital and acquired deafness.
- IHCs and OHCs possess distinct transcriptomes during development.
Purpose of the Study:
- Investigate chromatin-level regulation of differential gene expression in developing IHCs and OHCs.
- Explore differences in mRNA splicing between developing IHCs and OHCs.
- Determine if chromatin accessibility differences explain differential gene expression.
Main Methods:
- Bulk RNA-sequencing of developing mouse IHCs and OHCs to analyze transcriptomes.
- Bulk ATAC-sequencing of developing mouse IHCs and OHCs to map chromatin accessibility.
- Comparative analysis of RNA-seq and ATAC-seq data to link gene expression to chromatin states.
Main Results:
- Differential chromatin accessibility was observed in promoters of many differentially expressed genes in developing IHCs and OHCs.
- Both transient developmental genes and genes with sustained adult expression showed distinct chromatin accessibility.
- Alternative mRNA splicing and transcription start sites contribute to transcriptomic diversity.
- Cochlear hair cells exhibit unique promoters and mRNA isoforms not found in other cell types.
Conclusions:
- Differential gene expression in developing hair cell types is controlled by pre- and post-transcriptional mechanisms.
- Unique promoters and mRNA isoforms in cochlear hair cells underscore the significance of studying rare cell type transcriptomes and epigenomes.
- A publicly accessible resource for visualizing gene promoters and mRNA isoforms in neonatal hair cells is provided.
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