Single molecule, long-read Apoer2 sequencing identifies conserved and species-specific splicing patterns

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Apolipoprotein E receptor 2 (Apoer2) is a key synaptic receptor in the brain.
• Apoer2 binds the disease-associated ligand Apolipoprotein E (Apoe).
• Alternative splicing (AS) of Apoer2 generates significant transcriptomic diversity.

Purpose of the Study:

• To investigate conserved alternative splicing of Apoer2 exons across vertebrate species.
• To identify species-specific splicing events and their functional implications.
• To characterize the full-length Apoer2 isoform repertoire in mammalian brains.

Main Methods:

• Comparative analysis of Apoer2 exon splicing across vertebrate species.
• Single-molecule, long-read RNA sequencing for full-length transcript profiling.
• Bioinformatic analysis to identify and quantify unique Apoer2 isoforms.

Main Results:

• Identified evolutionary gain of exons in mammals (cytoplasmic, furin inserts) and loss in primates (LDLa repeat).
• Discovered 68 unique full-length Apoer2 transcripts in mouse and 48 in human cerebral cortex.
• Found tandem skipping of exons encoding EGF-precursor like repeat and glycosylation domain specifically in mice.

Conclusions:

• Apoer2 exhibits significant isoform complexity and species-specific alternative splicing patterns in the vertebrate brain.
• Splicing variations in Apoer2 likely contribute to functional diversity and altered receptor properties.
• These findings provide novel insights into the evolution of synaptic receptor diversity.