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. Author manuscript; available in PMC: 2016 Apr 19.
Published in final edited form as: Mol Microbiol. 1993 Apr;8(1):143–157. doi: 10.1111/j.1365-2958.1993.tb01211.x

Fig. 4.

Fig. 4

Schematic diagram for construction of the isogenic strains DP-L1510 and DP-L1535, in which readthrough transcription of prfA was blocked.

A. Chromosomal integration of pDP1498 by homologous recombination between the cloned Pstl (P)- and EcoRI (E)-generated fragment present on the plasmid and the homologous chromosomal sequence. The designated cross-over points are arbitrary. P1 and P2 indicate the two promoter elements immediately upstream of prfA while PplcA indicates the single plcA promoter (Mengaud et al., 1989; 1991; N. Freitag unpublished).

B. The resulting integration structure on the chromosome of both mutant strains. The integration strains were selected for, and maintained by, growth at a non-permissive temperature for plasmid replication in the presence of chloramphenicol. The plasmid was shown by Southern blot analysis to have integrated multiple times in a head-to-head configuration (data not shown).