Production of Recombinant Neurotrophic Factors

The introduction of recombinant technology has dramatically influenced progress in the studies of many proteins and systems. In the areas of neurochemistry and neurobiology, perhaps the most notable effect has been on work with nerve growth factor (NGF), and its related protein family members, brainderived neurotrophic factor (BDNF or NT-2), and neurotrophin3 (NT.-3). The potential of producing mg and larger quantities of these agents will expedite our understanding of their functions and biological interrelationships and enable us to examine their therapeutic potential (Thoenen and Barde, 1980; Phelps et al., 1989). Each of these agents shares common or similar characteristics, including: precursor configuration and processing sites, molecular size, strong basicity, noncovalent dimerism, conserved cysteine residues with common or predicted disulfide-bridging identity, and 50–70% interspecies amino acid sequence homology of the mature forms (see K. Nikolics, this volume). These characteristics (see Table 1) have been used, coupled with the long history of NGF isolation from natural sources (for a recent review, see Long0 et al., 1989), to form the basis of a generic approach to research scale production of theneurotrophins (NTs) described here. It is the purpose of this chapter to summarize briefly some of the information available on the expression of the NTs followed by a strong focus on the approach to the purification and characterization of the recombinant products.