Cytosine deaminase as a negative selection marker for gene disruption and replacement in the genus Streptomyces and other actinobacteria.

We developed a novel negative selection system for actinobacteria based on cytosine deaminase (CodA). We constructed vectors that include a synthetic gene encoding the CodA protein from Escherichia coli optimized for expression in Streptomyces species. Gene disruption and the introduction of an unmarked in-frame deletion were successfully achieved with these vectors.