Incompatibility of Escherichia coli rho mutants with plasmids is mediated by plasmid-specific transcription.

AUTOR(ES)

Li, T K

RESUMO

The Escherichia coli rho-15 mutant (deficient in transcription termination) is known to be incompatible with pBR322 and other plasmids (J. S. Fassler, G. F. Arnold, and I. Tessman, Mol. Gen. Genet. 204:424-429, 1986). We show that failure of pBR322 to transform rho-15 is mediated by transcription from the tet promoter and readthrough from the tet gene into the rom region. Using an isopropyl-beta-D-thiogalactopyranoside-inducible promoter to replace the tet promoter, we have demonstrated that plasmid-specific transcription inhibits growth of the rho-15 host, possibly due to the expression of the Rom protein. The involvement of Rom protein in pBR322-rho-15 incompatibility is further indicated by the following two experiments. (i) Functional inactivation of the rom gene in pBR322 enabled plasmids to transform E. coli rho-15. (ii) Specific overexpression of the rom gene abolished plasmid transformation into E. coli rho-15. An rpoB8(Ts) mutant RNA polymerase which compensated for the termination defect in E. coli rho-15 also restored plasmid-host compatibility, suggesting that Rom-mediated plasmid-host incompatibility is linked to a defect in transcription termination.

Documentos Relacionados

• ColV plasmid-specific aerobactin synthesis by invasive strains of Escherichia coli.
• Plasmid-Specific Transformation in Staphylococcus aureus
• VirA, the plant-signal receptor, is responsible for the Ti plasmid-specific transfer of DNA to maize by Agrobacterium.
• Mutagenesis of the Tra1 core region of RK2 by using Tn5: identification of plasmid-specific transfer genes.
• Nucleotide sequence of the genome of Pf3, an IncP-1 plasmid-specific filamentous bacteriophage of Pseudomonas aeruginosa.