Production and characterization of polyclonal antibodies against chicken myostatins

x, 101 leavesMyostatin is a new member of the transforming growth factor-beta superfamily of secreted growth and differentiation factors. Myostatin is almost exclusively expressed in skeletal muscle and act as a negative regulator of skeletal muscle growth. Because anti-myostatin antibodies will be useful in investigating the mechanism of action of myostatin, an experiment was designed to produce polyclonal anti-chicken-myostatin antibodies. A PCR amplified prepro-myostatin composed of the prodomain plus mature myostatin and a C- terminal fragment containing only the mature myostatin were cloned into an expression vector, and these proteins were expressed in E. coli. The recombinant proteins were fractionated by SDS-PAGE, then the myostatin bands were cut out and electro-eluted to obtain purified myostatins. Rabbits were immunized with the purified myostatins to produce polyclonal anti-myostatin antibodies. IgGs were separated from the rabbit sera using Protein A affinity chromatography. Antibody binding characteristics were then examined using Western blot analysis of various chicken tissues. Both polyclonal antibodies demonstrated a strong affinity to both form of recombinant myostatin in Western blot analysis. The anti-mature myostatin antibody showed binding affinity to proteins at 50, 30 and 20 kD in skeletal muscle and liver. No specific binding in skeletal muscle was demonstrated by the anti-mature myostatin antibody, suggesting that the above proteins are non-myostatin proteins that have affinity to anti-mature myostatin antibody. In contrast, the anti-prepro-myostatin antibody showed affinity to a 37 kD band only in skeletal muscle in addition to the 50, 30 and 20 kD bands. Since the molecular weight of the myostatin prodomain is known to be close to 37 kD, it is postulated that the 37 kD protein specifically recognized by the antiprepro- myostatin in skeletal muscles is likely to be a myostatin prodomain with further validation of its binding specificity, the anti-prepro-myostatin antibody generated in this study will potentially be useful in investigating the mechanism of action of myostatin