Cloning and Sequence Analysis of Insulin-like Growth Factor-1 Gene in Haemonchus contortus Resistant Malpura Sheep

Insulin-like growth factor-1 (IGF-1) is a low molecular weight peptide produced mainly by liver cells and plays an important role in regulating postnatal growth. Recently, IGF-1 has been implicated as a marker for resistance against gastrointestinal nematodes in sheep. A study was conducted to find out the sequence information of IGF-1 gene in Haemonchus contortus-resistant Malpura sheep. Total RNA was extracted from liver tissue collected from Haemonchus contortusresistant Malpura sheep and complementary DNA was synthesized. Polymerase chain reaction (PCR) amplification of ovine IGF-1 gene was done using gene-specific primers. A 591 bp PCR product was amplified and characterized by nucleotide sequence for sequence variations. It showed 100% similarity with the sheep IGF-1 sequence available in the public domain. Deduced amino acid (154 residues) revealed close to goat and taurine cattle. The predicted local distance difference test (pLDDT) score of the protein was 55.78. At present, a sheep-specific antibody against protein is not available for the development of immunological assay. Thus, the present findings would be useful to generate recombinant ovine IGF-1 protein for the generation of antibodies for immunological investigation.