Jinyu  Zhang, Guoliang  Zhang, Runjun  Yang, Shuling  Niu, Wenlin  Bai, Dianfeng  Liu, Shenyang  Xing, Liang  Sun, Zhihui  Zhao, Yumin  Zhao, 
    Cloning and Characterization of Four New Splice Variants of <I>Insulin-Like Growth Factor-I</I> Gene in Chinese Red Steppes,
    Journal of Animal and Veterinary Advances,
    Volume 10,Issue 18,
    2011,
    Pages 2459-2464,
    ISSN 1680-5593,
    javaa.2011.2459.2464,
    (https://makhillpublications.co/view-article.php?doi=javaa.2011.2459.2464)
    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 <I>IGF-I</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&prime;ends sequences of IGF-I messenger 
  ribonucleic acid (mRNA) in Chinese red steppes liver were cloned by 3&prime;-Rapid 
  Amplification of cDNA Ends (3&prime;RACE) technique. Researchers found that 
  there are two types of 3&prime;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.
    Keywords: assembled;RACE;semi-quantitative RT-PCR;IGF-I;Chinese red steppes;China