Production of bioactive myostain propeptide of various animal species in E. coli

Abstract

M (MSTN) is a potent negative regulator of skeletal muscle growth in various animal species, thus there have been attempts to develop MSTN-inhibitory strategies to improve skeletal muscle growth in meat-producing animals as well as to treat muscle-wasting conditions in humans. MSTN propeptide (MSTNPro), the N-terminal part of unprocessed MSTN suppresses MSTN bioactivity by prevention of MSTN binding to its membrane receptor suggesting that MSTNPro is a potential candidate molecule to be used to suppress MSTN activity. To examine the potential of MSTNPro as an agent to improve skeletal muscle growth of meat producing animals in vivo, a large quantity of MSTNPro must be available. Since E. coli remains the most cost-effect system in high-yield production of recombinant proteins, we have attempted to produce bioactive MSTNPro in E. coli. Our first attempt demonstrated that rainbow trout MSTNPro was expressed in soluble forms using maltose binding protein as an N-terminal fusion partner. Affinity purified rainbow trout MSTNPro demonstrated MSTN-inhibitory activity in an in vitro assay system and the potency was not different from that of commercial mouse MSTN Pro produced in a eukaryotic system. In subsequent studies, bioactive MSTNPro of chicken, pig and mouse were produced using the same E. coli system. Interestingly, MSTN-inhibitory potencies were different among MSTNPros from different animal species. The ability to produce MSTNPro in a cost effective E. coli system is expected to make it easy to investigate the potentials of MSTNPro as a pharmaceutical agent to improve skeletal muscle growth of meat producing animals.