ATTACHMENT OF PROPHAGE-P2 - GENE ORDER AT DIFFERENT HOST CHROMOSOMAL SITES

Using P1 transduction, we have determined the position on the host chromosome of several different P2 prophage locations. In Escherichia coli C, location I maps between his and metG, and location II between metE and rha. In E. coli K-12, the position of location H is confirmed to be between shiA and his, and location II maps between metE and rha. P1 transduction was also used to determine the gene order in the prophage at three of these locations. At each location, the prophage map is a circular permutation of the vegetative map, in agreement with Campbell's model for attachment of episomes. The permutation is the same in each case, but the orientation of prophage genes (clockwise or counterclockwise) varies. Further evidence that P2 is inserted into the host chromosome according to Campbell's model comes from the finding that a prophage in location II reduces the linkage between the bacterial genes metE and rha, which map on either side of the prophage. © 1969.