Alternative Splicing Signatures in RNA-seq Data: Percent Spliced in (PSI)

Area of Science:

• Molecular Biology
• Genomics
• Bioinformatics

Background:

• Alternative splicing significantly increases protein diversity by selectively including or excluding exons.
• RNA-sequencing (RNA-seq) is a powerful tool for genome-wide analysis of post-transcriptional modifications like splicing.
• Understanding exon usage is crucial for deciphering gene expression regulation and protein function.

Purpose of the Study:

• To present a method for calculating the percent spliced in index (PSI) without prior knowledge of splicing patterns.
• To provide a quantitative, global assessment of exon usage from RNA-seq data.
• To enable visualization and comparison of novel splicing events across different conditions.

Main Methods:

• Utilizes RNA-seq reads to identify and quantify exon inclusion or exclusion events.
• Calculates the percent spliced in index (PSI) based on the ratio of reads supporting exon inclusion versus exclusion.
• Develops an exon-centric approach for visualizing and analyzing splicing patterns.

Main Results:

• The described protocol enables accurate PSI calculation, reflecting exon splicing efficiency.
• The method allows for a comprehensive, genome-wide snapshot of alternative splicing events.
• Identifies and visualizes novel and complex splicing patterns in an exon-centric manner.

Conclusions:

• This protocol offers a robust method for quantifying alternative exon usage and understanding splicing regulation.
• The PSI calculation is a valuable metric for assessing transcript isoform processing.
• The approach facilitates the integration with differential splicing analysis tools and comparative studies.