Fragment of 759 bp DNA spanning the Matrix 1 (M1) gene of Avian Influenza Virus (AIV) was inserted into an expression vector pET28c to construct a recombinant plasmid pET28c-M1. The pET28c-M1 plasmid was transformed into the Escherichia coli BL21 (DE3) competent cell to produce a recombinant strain E. coli 21 (DE3). After being induced by Isopropyl-b-D-galactopyranoside (IPTG), E. coli 21 (DE3) expressed a 28-kDa fusion protein at a high level. This protein can bind anti-AIV (H5N1) positive serum by Western-blot analysis. After being denatured, renatured, and purified by Ni2+-column, the fusio...