Single-cell mRNA isoform diversity in the mouse brain.

Area of Science:

• Molecular Biology
• Genomics
• Neuroscience

Background:

• Alternative messenger RNA (mRNA) isoform usage contributes significantly to protein diversity in mammals.
• While studied in bulk tissues, the extent of this diversity in individual cells remains largely unknown.

Purpose of the Study:

• To investigate alternative full-length mRNA isoform expression patterns in single mouse brain cells.
• To explore the implications of isoform diversity for protein diversity and biological variability at the single-cell level.

Main Methods:

• Utilized long-read sequencing technology.
• Incorporated unique molecular identifiers (UMIs) for precise mRNA quantification.
• Analyzed isoform expression in single cells from the mouse brain.

Main Results:

• Observed substantial mRNA isoform diversity in single cells, even with conservative definitions.
• Found that genes typically exhibit a few highly expressed isoforms and numerous low-level isoforms.
• Identified unique mRNA molecules for many genes, with events affecting coding regions, suggesting novel protein diversity.
• Noted fewer splicing errors in coding regions compared to non-coding regions, indicating selection.

Conclusions:

• Alternative mRNA isoform diversity is a significant contributor to biological variability in single cells.
• The study reveals previously unrecognized protein diversity arising from alternative splicing in individual cells.