The genomic structure and a novel alternatively spliced form of porcine pTα chain

A complete genomic nucleotide sequence for porcine pTα gene was obtained from a BAC clone, which revealed a novel exon 2 missing in human and murine counterparts. Cattle and dog genomic sequences showed the counterparts corresponding to porcine exon 2. Using thymocyte RNA and RT-PCR, three types of porcine pTα-chain cDNA sequences, pTα1, pTα2 and pTα3, were obtained. These three different cDNA sequences were alternatively spliced products with pTα1 consisting of exons 1, 2, 3, 4, and 5, pTα2 consisting of exons 1, 2, 4, and 5, and pTα3 consisting of exons 1, 2, 3 and the intron down stream of exon 3. pTα1 and pTα2 correspond to previously reported pTαa, and pTαb, respectively, and pTα3 is reported for the first time. Using RT-PCR, pTα3 appeared expressed predominantly in the thymocyte RNA. The chromosome location of pTα was investigated using Radiation Hybrid Map and FISH, both of which revealed the location at SSC7q11–q12.