HTR4 alternative splicing in rat tissues. (A) Alternative splicing between HTR4 exons 2 and 4 detected by RT-PCRs using primers in exons 2 and 4. No exon 3 skipping is detected but inclusion of a novel exon 3a was detected and verified by cloning and sequencing. Labels indicating rat tissues are explained beneath panel B. (B) Alternative splicing between HTR4 exons 3 and 5 by RT-PCRs using primers in exons 3 and 5. Exon 4 skipping as well as inclusion of exon 3a and another novel exon 4a were detected. All RT-PCR products were cloned and validated by sequencing. (C) Sequences of novel exons detected in A and B. Exons in upper case, surrounding intronic regions in lower cases. Position of exon 3a according to UCSC rat assembly Nov. 2004: chr18:58,418,797–58,418,851 and position of 4a chr18:58,442,685–58,442,734. (D) Schematic drawing of the HTR4 gene and protein structure. Position of primers used for A and B are depicted above according exons, novel exons 3a and 4a are inserted into the gene structure. The parts of HTR4 protein encoded by each exon are indicated by dashed lines.
