Recombination and expression of a cloned fragment of the DNA of Bacillus subtilis bacteriophage SP01

Fragments of the DNA of bacteriophage SPO1 can be cloned in Bacillus subtilis , the natural host for SPO1. Clones of the same fragment are either stable or unstable, depending on the vector used. SPO1 DNA contains hydroxymethyluracil instead of thymine. The cloned fragments do not contain hydroxymethyluracil, even when it is present in the cell as a consequence of SPOT infection. Yet the cloned SPOT DNA is active both in expression of its genetic information and in recombination with superinfecting SPOT DNA. SPO1 gene 17, which is probably a late gene, is expressed from the cloned fragment regardless of the orientation of insertion, suggesting that it is transcribed from its natural promoter.