cDNA cloning, structural analysis, SNP detection and tissue expression profile of the IGF1 gene in Malabari and Attappady Black goats of India.

Insulin-like growth factor 1 (IGF1) plays an important role in growth, reproduction, foetal development and cell proliferation. The present study was conducted to clone and sequence the full-length coding sequence of the caprine IGF1 gene from Attappady Black and Malabari breeds, two indigenous goat breeds of south India, to analyse its structure, and to ascertain the relative abundance of IGF1 mRNA in different tissues. The caprine IGF1 cDNA (GenBank accession nos: KJ549851 and KJ549852) contained a 465-bp open reading frame encoding IGF1 protein with 154 amino acid residues. A novel SNP was detected in the 3'UTR region, g.931A>G. Genotyping was performed in 277 goats from the two genetic groups using the PCR-single strand conformational polymorphism (SSCP) and two genotypes, AA and AG were observed at this locus. IGF1 is a secretary pathway protein with 49 amino acid-long signal peptide with 19 phosphorylation sites. Caprine IGF1 amino acid sequence was 83-99% identical to other species with highest identity with the ruminants. Relative expression of IGF1 was highest in uterus and liver (P < 0.05), followed by oviduct and muscle. This work provided an important experimental basis for further research on the functions of IGF1 in goats.