Runjun  Yang, Chang  Liu, Zhihui  Zhaoa, Wenlin  Bai, Boxing  Sun, Yonghong  Zhang, 
    Cloning and Characterization of New Splice Variants of Insulin-Like Growth Factor-1 Gene in Songliao Black Pig,
    Journal of Animal and Veterinary Advances,
    Volume 11,Issue 17,
    2012,
    Pages 3125-3131,
    ISSN 1680-5593,
    javaa.2012.3125.3131,
    (https://makhillpublications.co/view-article.php?doi=javaa.2012.3125.3131)
    Abstract: Insulin-Like Growth Factor 1 (<i>IGF-1</i>) is a single copy 
  gene. It generates several IGF-1 mRNA variants due to alternative splicing. 
  Spliced variants of IGF-1 being some small peptides derived from spliced variants 
  of IGF-1 have critical roles in cell metabolism and growth of various vertebrate 
  species. Porcine <i>IGF-1</i> gene has two promoters and the existence of Exon 
  6 has been confirmed in Songliao Black pig in the laboratory. The aims of the 
  present study were to identify new spliced variants of <i>IGF-1</i> gene including 
  Exon 5 and to investigate their expression profile in different tissues of Songliao 
  Black pig. The cDNAs of two new spliced variants of <i>IGF-1</i> gene were cloned 
  by RACE. These two variants were named Class I IGF-1-Eb and Class II IGF-1-Eb, 
  respectively. The Class I IGF-1-Eb contains an Open Reading Frame (ORF) of 564 
  bp encoding 187 amino acids (GenBank Accession No. FJ914497). The Class II IGF-1-Eb 
  contains an ORF of 516-bp encoding 171 amino acids (GenBank Accession No. FJ914498). 
  Tissue distributions of mRNAs of Class I IGF-1-Eb and Class II IGF-1-Eb were 
  investigated in Songliao Black pig by semi-quantitative RT-PCR. Both of the 
  new mRNA variants were expressed in a variety of tissues. Class I IGF-1-Eb mRNA 
  was more abundant than Class II IGF-1-Eb mRNA in most tissues except for duodenum 
  and longissimus muscle (p&lt;0.05).
    Keywords: Insulin-Like Growth Factor 1 (IGF-1);alternative splicing;Songliao Black pig;tissues;expression