Authors : Jinyu Zhang, Guoliang Zhang, Runjun Yang, Shuling Niu, Wenlin Bai, Dianfeng Liu, Shenyang Xing, Liang Sun, Zhihui Zhao and Yumin Zhao
Abstract: Insulin-like Growth Factor-I (IGF-I) is a very important candidate gene which generates several IGF-I mRNA variants. Because of its alternative splicing this gene is involved in very complex biological functions such as the mediation effect of promoting the growth activities of growth hormone. The mammalian IGF-I gene contains 6 exons of which exon 1 and 2 produced various leader sequences and exon 5 and 6 produced different E domain by different splicing forms. In this study, the 3′ends sequences of IGF-I messenger ribonucleic acid (mRNA) in Chinese red steppes liver were cloned by 3′-Rapid Amplification of cDNA Ends (3′RACE) technique. Researchers found that there are two types of 3′ends sequences containing exon 5 (Eb) and 6 (Ea) in Chinese red steppes. According to the result of 3'RACE and the reports about leader exons, we have assembled the possible transcripts; type Ea of class 1, type Eb of class 1, type Ea of class 2 and type Eb of class 2. Semi-quantitative RT-PCR was used to identify the distribution of these four new transcripts of IGF-I mRNA expression in Chinese red steppes. The results show that type Ea of class 1 was expressed in all tissues tested whereas, the type Eb of class 1, the type Ea of class 2 and the type Eb of class 2 were expressed in minority tissues examined. The study shows that class 1 IGF-I mRNA has higher expression than class 2 and that type Ea of class 1 is expressed in the highest mRNA level.
Jinyu Zhang, Guoliang Zhang, Runjun Yang, Shuling Niu, Wenlin Bai, Dianfeng Liu, Shenyang Xing, Liang Sun, Zhihui Zhao and Yumin Zhao, 2011. Cloning and Characterization of Four New Splice Variants of Insulin-Like Growth Factor-I Gene in Chinese Red Steppes. Journal of Animal and Veterinary Advances, 10: 2459-2464.