Can changes in SR protein acetylation affect alternative splicing?

Cellular phenotype and function is determined by the cellular proteome. Within the cellular proteome there are processes that have a potential to significantly alter the composition of the proteome. One such process is called alternative splicing. Splicing is the removal of introns from a pre-mRNA sequence and the remaining pre-mRNA sequences, called exons, are combined. Alternative splicing modifies the intron-exon combination, and can form novel products from the different arrangement of the coding sequences. This process, due to the high potential for new, possibly unwanted products, is highly regulated and can occur in a tissue and developmental-specific fashion. The misreguation of alternative splicing has been documented in many human diseases. The regulation of alternative splicing involves a complex network of proteins and RNA. Serine-arginine repeat (SR) proteins are a known family of regulatory proteins that bind within exons to promote exon inclusion into the mature mRNA transcript. SR protein activity is regulated by the post-translational modification, phosphorylation. Another post-translational modification of SR proteins known as acetylation has recently been identified. The acetylation of lysine residues on proteins can result in changes in localization, function, and/or structure of modified proteins. The location and function of this post-translational modification on SR proteins has not been determined. Cellular acetylation status of the HepG2 cell line was increased by histone deacetylase (HDAC) inhibition, using the HDAC inhibitors MS-275 and SAHA. RNA from treated cells was isolated for use with RT-PCR arrays developed by Peter Stoilov. Western blotting was used to determine efficacy of HDAC inhibitors on total cellular acetylation. The future goal is to understand how acetylation affects alternative splicing and characterize a new post-translational modification of SR proteins