Expression and analysis of thymosin α1 concatemer in Escherichia coli

Tα1 (thymosin α 1) is important in treating immunodeficiency and other diseases. In order to study the feasibility of expressing Tα1 in plants, as the first attempt, we designed and synthesized the T α 1 gene according to the plant codon usage preference and constructed the 4×Tα1 concatemer (four copies of a DNA sequence arranged end‐to‐end in tandem). The latter was inserted into Escherichia coli expression vector pQE30, resulting in a recombinant plasmid that was subsequently transformed into E. coli M15. The 4×Tα1 concatemer protein was successfully expressed in E. coli in a soluble form. The expressed protein was purified and its bioactivity was analysed by MTT [3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2 H ‐tetrazolium bromide] assay. Preliminary results showed that the 4×Tα1 concatemer protein could stimulate the mice spleen lymphocyte proliferation. This is the first report on the expression of 4×Tα1 concatemer that was synthesized according to plant codon usage preference in an E. coli expression system. The present study provides the basis for expressing the synthesized active T α 1 gene in plants in the future.