Comprehensive analysis of mutually exclusive alternative splicing in C. elegans.

Area of Science:

• Molecular Biology
• Genetics
• RNA Biology

Background:

• Alternative pre-mRNA splicing is a key mechanism for gene regulation.
• Mutually exclusive (ME) splicing, a rare form of alternative splicing, involves selecting only one exon from a cluster.
• The regulatory mechanisms governing ME splicing in vivo remain largely uncharacterized.

Purpose of the Study:

• To experimentally identify and characterize mutually exclusive exon clusters in C. elegans.
• To elucidate the repertoire of regulatory mechanisms controlling ME splicing in vivo.

Main Methods:

• Experimental exploration of putative ME exon clusters in C. elegans.
• Analysis of exon-intron structures and identification of homologous exons.
• Investigation of the role of nonsense-mediated mRNA decay (NMD) in ME splicing fidelity.

Main Results:

• 29 ME exon clusters within 27 genes were confirmed to be selected in a mutually exclusive manner.
• Twenty-two of these clusters involved homologous ME exons.
• Five clusters featured short intervening introns, posing challenges for excision.
• Nonsense-mediated mRNA decay (NMD) was found to be crucial for the fidelity of ME splicing in 14 clusters.

Conclusions:

• This study characterizes the complete repertoire of ME splicing in C. elegans.
• Identified ME exon clusters and their structural features provide insights into splicing regulation.
• The involvement of NMD highlights a conserved quality control mechanism in ME splicing fidelity.