Expression of Cre recombinase during transient phage infection permits efficient marker removal in Streptomyces

We report a system for the efficient removal of a marker flanked by two loxP sites in Streptomyces coelicolor, using a derivative of the temperate phage phi C31 that expresses Cre recombinase during a transient infection. As the test case for this recombinant phage (called Cre-phage), we present the construction of an in-frame deletion of a gene, pglW, required for phage growth limitation or PgI in S. coelicolor. Cre-phage was also used for marker deletion in other strains of S. coelicolor.