The maintenance affinities of KLF-1 proximal F merogenotes in Escherichia coli.

In conjugation with donor strains carrying proximal F merogenotes of KLF-1 type about 100-fold lower frequency of Leu+ or Lac+ recombinants was found. The determination of the level of beta-galactosidase synthesis during the initial period of mating indicated that the transfer process of plasmid DNA was not impaired. Among the recombinants selected a large fraction have not expressed the plasmic fertility functions. This phenomenon was found to be replicon specific and was observed only with proximal F merogenotes but not with classical F'lac and F'ORF-1 elements or R1-19 plasmid. The expression of KLF-1 plasmid functions in the cell seems to be affected by a chromosomal gene of the proximal F merogenote closely linked to leu marker.