| 摘要 |
<p>A vector suitable for cloning and expressing heterologous DNA in host cells of a given type (in particular gram positive, including Bacillus especially B.subtilis, B.pumilis or B.amyloliquefaciens host cells) and a process for obtaining these vectors is described. Vectors are derived from plasmids which are normally stably maintained in the given host cells by cloning a cassette of heterologous DNA comprising a selectable marker, at least one unique restriction site not found in the plasmid and optionally also a transcription terminator and promoter into a non-unique site of the plasmid, followed by selection of the resultant vectors for stable maintenance in the given host cells. This approach maximises the chance of obtaining a stable vector as the likelihood of finding a position on the plasmid where insertion of DNA does not interrupt a region essential or important for replication and stable maintenance is greatly increased. Specific Bacillus vectors are described (pPOD2152, pPOD2154, pPOD2158, pPOD2161, pPOD2167 and pPOD2168) which have been found to maintain cloned heterologous DNA with 100 % stability for at least 70 generations.</p> |
