RNA-polymerase binding sites within the tra region of the F factor of Escherichia coli K-12.

Chimeric plasmids containing the tra operon of the Escherichia coli K-12 F factor were used to map by electron microscopy the RNA polymerase binding sites within the contiguous F EcoRI restriction fragments f6, f16, f1, f17, f19 and f2. [These fragments have been previously cloned in the EcoRI site of pSC101 to give the chimeric plasmids pRS27 (f6, f15), pRS29 (f15, f1) and pRS31 (f17, f19 and f2)]. The results may reflect the presence of a number of previously unrecognized promoters within the traY----Z operon.