Heterologous expression and characterization of Indian Sahiwal cattle (Bos indicus) alpha inhibin

Inhibin is a non-steroidal glycoprotein hormone of gonadal origin with major action as negative feedback control of the production of FSH by the anterior pituitary gland. The physiological role of inhibin has led to the development of inhibin immunogens for fertility enhancement in farm animals. It is envisaged that a reduction of endogenous inhibin secretion would increase FSH concentrations and thus offers a potential for increasing the number of ovulatory follicles in the ovary. The present work was carried out to produce recombinant bovine (Indian Sahiwal Cattle; Bos indicus) alpha inhibin (bINH-α) in E. coli by optimizing its expression and purification in biologically active form and to study its immunological characterization. A bacterial protein expression vector system based on the phage T(5) promoter was used. The bINH-α encoding gene was successfully cloned and expressed in E. coli and the purified recombinant bINH-α was characterized. Recombinant bINH-α (25 µg mL(-1)) immunized guinea pigs had a significant increase in litter size compared to the control group. These results indicate a role for recombinant bINH-α as a fecundity vaccine to enhance the ovulation rate and litter size in animals.