Genomic HEXploring allows landscaping of novel potential splicing regulatory elements

Area of Science:

• Molecular Biology
• Genetics
• Bioinformatics

Background:

• Splicing regulatory elements (SREs) control splice site selection, influencing gene expression.
• Current computational methods for identifying SREs have limited predictive power for mutation effects.

Purpose of the Study:

• To develop a novel computational score, HEXplorer, for predicting the impact of mutations on SREs.
• To quantitatively assess the effects of mutations on splice site usage.

Main Methods:

• Defined a hexamer-based 'HEXplorer score' using average Z-scores of overlapping hexamers.
• Applied the HEXplorer score to analyze splice site neighborhoods and mutation effects.
• Utilized the HIV-1 pre-mRNA as a model system to validate the score with 29 mutations.

Main Results:

• HEXplorer score profiles reflected splice-enhancing and silencing properties of genomic regions.
• Differences in HEXplorer scores between mutant and reference sequences accurately predicted exonic mutation effects on splice site usage.
• Achieved excellent correlation between splicing activity and HEXplorer score for 29 HIV-1 mutations, identifying five novel SREs and optimizing a known silencer.

Conclusions:

• The HEXplorer score provides a quantitative measure of mutation effects on splicing regulatory elements.
• This method enables the landscaping of splicing regulatory regions and prediction of mutationally most effective nucleotides.
• HEXplorer score offers improved predictive power for understanding gene regulation and disease-associated mutations.