Development of a pair of bifunctional expression vectors for Escherichia coli and Bacillus licheniformis.

A pair of bifunctional expression vectors, pBL-WZX and pHY-WZX, for Escherichia coli and Bacillus licheniformis was constructed to express interesting genes in a secretory manner. The vectors contain an expression cassette consisted of the promoter and signal peptide region of B. licheniformis amyL as well as an artificial multiple cloning site and a terminator and utilize kanamycin-resistance and/or tetracycline-resistance for selection in both B. licheniformis and E. coli. Both vectors contain a part of 3' terminal fragment of B. licheniformis amyL. The 5'-terminal or 3'-terminal fragment of B. licheniformis amyL can cause the integration and amplification of expression cassette in the chromosome of B. licheniformis under a kanamycin-selection pressure. pBL-WZX is an integrational vector while pHY-WZX is free one for B. licheniformis. Both vectors were succeeded in secretory expression of manL in both B. licheniformis and E. coli.