Alternative transcripts were identified searching ExonHit Therapeutics SpliceArray portal (http://portal.splicearray.com) and blasting exon-intron boundary sequences against human cDNA libraries. For semi-quantitative evaluation of transcript ratio differences, primers flanking the common 5′ splice donor site in exon 29 (forward primer: 5′-TTGGGCCCTCCTGTGATA-3′, location shown in Figure S1A) and the alternative 3′ splice acceptor site in exon 30 (reverse primer: 5′-TGGCAGCACCTTTGTTTGTA-3′, location shown in Figure S1A) were used to simultaneously amplify all four transcript forms (Figure S1A). The fragments were separated on a 3.5% NuSieve agarose gel and direct sequencing was used to confirm expected transcript forms. Taqman-based real time PCR was used to quantitatively determine ratios of alternative transcripts in human brain tissue. Assays were custom designed through Applied Biosystems by targeting unique exon-exon boundaries (for primer and probe sequences see Text S1). β-actin mRNA expression level was quantified using a commercially available Taqman assay (Applied Biosystems). Fluorescence outputs were quantified in real time using a 7900HT Fast Real Time PCR System and the data were analyzed using SDS software v.2.2.2 (Applied Biosystems). One way analysis of variance was used to determine
