TY - JOUR
T1 - Incompatibility of Escherichia coli rho mutants with plasmids is mediated by plasmid-specific transcription
AU - Li, Tsai Kun
AU - Panchenko, Yuri A.
AU - Drolet, Marc
AU - Liu, Leroy-Fong
PY - 1997/9
Y1 - 1997/9
N2 - 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-β-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.
AB - 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-β-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.
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M3 - Article
C2 - 9294436
AN - SCOPUS:0030883563
VL - 179
SP - 5789
EP - 5794
JO - Journal of Bacteriology
JF - Journal of Bacteriology
SN - 0021-9193
IS - 18
ER -