CORRELATION OF A SUBSET OF THE PLC PLASMIDS TO THE PHYSICAL MAP OF ESCHERICHIA-COLI K-12

We determined map positions of the Escherichia coli K-12 portions of a subset of the hybrid E. coli-ColE1 plasmids constructed by Clarke and Carbon. The probe DNA of pLC plasmids was labeled with digoxigenine-dUTP, hybridized to the 476 phage clones of the E. coli ordered clone bank miniset, which was adsorbed on a strip of nylon membrane filters, and detected by enzyme-linked immunoassay and a subsequent enzyme-catalyzed color reaction. The total number of Clarke-Carbon plasmids we analyzed was 518, for which chromosomal locations of 297 clones were newly determined in the present study. Another 180 plasmids gave results that agreed with those reported previously, and the remaining 41 plasmids gave map positions different from those described in the previous report. A chromosome map of E. coli which shows the locations of 518 pLC plasmids on it is presented, as well as a table which correlates the pLC plasmids with the clones of the E. coli ordered clone bank miniset on the basis of the hybridization data. We estimate that approximately one-half of the entire genome of E. coli was covered by the pLC plasmids used in this study.