High-level expression of biologically active chicken prolactin in E. coli

Abstract

1. 1. A large quantity of chicken prolactin (cPRL) was produced by manipulating the cPRL cDNA clone and an expression vector pKK223-3. To augment the production of the hormonal protein in E. coli, in addition to the potent tac promoter, a unique DNA linker containing a pair of Shine-Dalgarno sequences and a short preceding cistron sequence was inserted into adjacent 5'-region of the coding region. 2. 2. In sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis, recombinant cPRL protein exhibited a molecular mass of 23 kDa. 3. 3. The recombinant cPRL showed equivalent binding kinetics to an antiserum raised against turkey PRL. Also, this product increased the weight of pigeon crop sac mucosa to a degree comparable to that induced by turkey PRL. 4. 4. These results indicate that this recombinant cPRL has immunological and biological activities identical to those of authentic avian PRL.