Clinical relevance of alternative splicing

The unique phenomenon of alternative splicing is gathering concern due to its promising therapeutic potential. The human genome sequencing project suggests approximately 20,000-25,000 genes. Among these, about 35-60% of genes generate multiple mRNAs by alternative splicing mechanism and contribute to the diversity of the proteomic world. This 'gene shortfall' has ignited considerable interest in alternative RNA splicing. This process leads to expression of a single gene responsible for the transcription of different mRNA isoforms that might have multiple biological functions. The disruption of splicing pattern can produce aberrant splice variants, which are implicated in more than 50% of genetic disorders including cancer. Altered splice sites in neoplastic cell contribute to the development, progression and/or maintenance of tumorous growth. The repertoire of tumor-specific variant represents a potential marker in pharmacogenomic diagnostic relevance. Alternative splice isoforms have been analyzed serendipitously by qualitative gene profiling with in silico gene prediction software. Computational approach in identifying exonic splicing enhancers in genomic DNA and focus on microarray technology will elucidate differential expression of alternative splice variants. The antisense oligonucleotides modulate alternative splicing and engender the production of therapeutic gene products. Oligonucleotides have the potential to silence the mutations caused by aberrant splicing. The efficacy of the antisense oligonucleotides lies in the chemical configuration, affinity and delivery strategies. Hence the therapeutic potential of antisense oligonucleotides as modulators of aberrant alternative splicing would be a major challenge to the upcoming proteomic era.