Novel alternative splice variant of IGF-1R and its mRNA expression patterns in BaMa and Landrace pigs

The transcript variants of Insulin-like growth factor 1 receptor (IGF-1R) and their expression profiles had never been illuminated in pigs until now. Herein, we identified IGF-1R AS02 as a novel splice variant of IGF-1R gene by RT-PCR and analyzed its mRNA expression level by qRT-PCR in liver, cartilage and muscle tissues, while also detecting the single-nucleotide polymorphism (SNP) site near the splice site of the IGF-1R gene (in intron 19) of BaMa and Landrace pigs. Results demonstrated that the IGF-1R AS02 variant showed a significantly (P less than 0.05) higher expression level in cartilage than in muscle and liver across two pig breeds respectively. The expression level of the normal transcript (IGF-1R ISO01) of IGF-1R in cartilage was markedly lower than that in the other two tissues (P less than 0.05). In cartilage, IGF-1R ISO01 expression was higher in BaMa than in Landrace (P less than 0.05), while the expression level of IGF-1R AS02 was lower in BaMa than in Landrace (P less than 0.05). The SNP was detected in intron 19 of the IGF-1R gene of BaMa and Landrace pigs. These results contributed to facilitating a better understanding of IGF-1R gene in pigs.