FIG. 1.

Genetic organization of CUS-1 in E. coli K1. CUS-1 is an approximately 10-kb genetic element integrated into the XerC recognition site (5′-ATTGGTGCGCATAATGTA-3′) of the strain RS218 dif locus (triangle labeled attR); there is a duplication (with one nucleotide difference) of this site at the other end of the phage (triangle labeled attL). The relative sizes (in kilobases) and the directions of transcription of the various ORFs are indicated by the large arrows. The small arrows over selected ORFs indicate PCR primers used to amplify the ORFs (Table 1). Each ORF is identified by a letter or number designation.