A novel replication element from an Antarctic plasmid as a tool for the expression of proteins at low temperature

Genetic manipulation of Antarctic bacteria has been very limited so far. Th is article reports the isolation and molecular characterization of a novel plasmid. pMtBL, from the Antarctic gram-negative bacterium Pseudoalteromona s haloplanktis TAC 125. This genetic element, 4,081 bp long, appeared to be a multicopy cryptic replicon with no detectable transcriptional activity. By an in vivo assay, the pMtBL autonomous replication sequence was function ally limited to an AluI plasmid fragment of about 850 bp. This novel cold-a dapted replication element showed quite a broad host range profile; it was cloned into a mesophilic genetic construction, obtaining a cold-adapted exp ression vector that was able to promote the production of P. haloplanktis A 23 alpha -amylase in a psychrophilic bacterium. This study represents the f irst report of successful recombinant production of a cold-adapted protein in an Antarctic host.