The right end of transposable bacteriophage D108 contains a 520 base pair protein-encoding sequence not present in bacteriophage Mu.

We have cloned and characterized the right end terminal 796 bp of the transposable Mu-like bacteriophage D108. This region encompasses a 520 bp region of D108-specific sequences not present in phage Mu that contain an open reading frame encoding a 12 KDa protein. This protein can be visualized in vivo when the region is placed downstream from the strong lac UV5 promoter. The open reading frame can be expressed from the dam-regulated mod promoter (for modification of D108 DNA), yet also contains its own dam-independent promoter for expression that is detectable by northern blot analysis late in the D108 lytic cycle. Comparison of this region of D108 DNA with the corresponding region of Mu DNA suggests that a complex rearrangement has occurred at the phages' right ends during their evolution.