Discovery of tissue-specific exons using comprehensive human exon microarrays

Area of Science:

• Genomics
• Molecular Biology
• Bioinformatics

Background:

• Higher eukaryotes exhibit complex transcriptomes due to alternative splicing.
• Existing gene expression monitoring methods require adaptation for transcript variation detection.

Purpose of the Study:

• To develop and apply a comprehensive exon microarray for detecting tissue-specific alternative splicing.
• To identify novel alternative splicing events and assess the frequency of differential splicing.

Main Methods:

• Design of a high-density oligonucleotide microarray targeting over one million human exons.
• Normalization of exon signals to gene-level signals.
• RT-PCR and sequencing for validation of identified splicing events.

Main Results:

• Identification of tissue-specific exons across 16 normal adult human tissues.
• Validation of approximately 86% of predicted tissue-enriched probesets.
• Evidence suggesting up to 73% of detected genes are differentially alternatively spliced.
• Discovery and validation of 17 novel tissue-specific exons from 11 genes.

Conclusions:

• Comprehensive exon microarrays, coupled with a simple algorithm, effectively detect tissue-specific alternative splicing.
• The study highlights significant expression beyond annotated regions and a high prevalence of alternative splicing.
• Identified novel exons and tissue-specific splicing patterns provide valuable data for understanding alternative splicing regulation.