A Mud(Ap, lac) prophage has been shown to be inserted into the ptsH gene of E. coli. The insertion is likely to have generated an operon fusion revealing antisense transcription at this locus. This suggests that the ORF previously identified, overlapping with ptsH ORF in the opposite orientation, might be functional. A model of regulation for the ptsH-ptsI-crr operon transcription is presented which accounts for antisense transcription.