Effects on mRNA degradation by Escherichia coli transcription termination factor Rho and pBR322 copy number control protein rop

Sozhamannan, Shanmuga; Stitt, Barbara L.

doi:10.1006/jmbi.1997.1004

Cited by 25 publications

(17 citation statements)

References 74 publications

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“…Moreover, deletion of rppH, which triggers mRNA degradation (12), also increased BCM sensitivity. Both of these results are consistent with the theory that Rho is involved in RNA turnover (32). It is possible that stabilization of the kilR transcript accounts for the hypersensitivity of these mutants, although an overall increase in RNA and RNA-DNA hybrids, toxic in Rho-deficient cells, is not ruled out.…”

Section: Discussionsupporting

confidence: 86%

Single-Gene Deletion Mutants of Escherichia coli with Altered Sensitivity to Bicyclomycin, an Inhibitor of Transcription Termination Factor Rho

Tran¹,

Baarsel²,

Washburn

et al. 2011

J Bacteriol

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We have screened the entire KEIO collection of 3,985 single-gene knockouts in Escherichia coli for increased susceptibility or resistance to the antibiotic bicyclomycin (BCM), a potent inhibitor of the transcription termination factor Rho. We also compared the results to those of a recent study we conducted with a large set of antibiotics (A. Liu et al., Antimicrob. Agents Chemother. 54:1393-1403, 2010). We find that deletions of many different types of genes increase sensitivity to BCM. Some of these are involved in multidrug sensitivity/ resistance, whereas others are specific for BCM. Mutations in a number of DNA recombination and repair genes increase BCM sensitivity, indicating that DNA damage leading to single-and double-strand breaks is a downstream effect of Rho inhibition. MDS42, which is deleted for all cryptic prophages and insertion elements In Escherichia coli, the ATP-dependent RNA-DNA helicase Rho (2, 31) terminates transcription at numerous sites (5, 10, 34). A recent study (4) revealed that critical Rho-dependent E. coli terminators are found in the cryptic prophages. Thus, Rho, aided by its cofactors NusA and NusG, is required to terminate transcription upstream of toxic foreign genes. Rho is the target for the antibiotic bicyclomycin (BCM) that binds specifically to Rho and inhibits its action (21, 39). BCM enhances transcription of horizontally transferred genes, including the various cryptic prophage genes that are otherwise silenced (4). One of these, the kil gene of the cryptic rac prophage, is lethal to the cell when expressed (18) and represents a major cause of cell death upon Rho inactivation. Cells lacking the kil gene are still sensitive to BCM but only at higher concentrations than that for the wild type (4).What other pathways render cells sensitive to Rho inactivation? Previous work identified a number of recombinational repair functions that sensitized cells to rho mutations (17). We recently showed that Rho prevents replication fork collapse caused by transcription overrunning replication, resulting in DNA double-strand breaks (36). We wished to determine if other functions were involved in protecting the cell from BCM (intrinsic resistance). We therefore screened the KEIO collection (1) of 3,985 individual E. coli gene deletion mutants to identify mutants hypersensitive to BCM. All KEIO deletions were deliberately constructed so that the kan promoter is directed downstream and the kan gene is followed by no known terminator. This eliminates effects from transcriptional polarity, although translational polarity may, in some cases, still be possible. These mutants were compared with those in a similar study we carried out with 22 other antibiotics (23). We show that many different types of functions protect against Rho inactivation and that mutants lacking some of these functions sensitize the cell to BCM even in the absence of Kil function and other cryptic prophage genes. MATERIALS AND METHODSSynergy experiments. BW25113 (11) was used in minimal medium A containing glucose (27)...

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Section: Discussionsupporting

confidence: 86%

Single-Gene Deletion Mutants of Escherichia coli with Altered Sensitivity to Bicyclomycin, an Inhibitor of Transcription Termination Factor Rho

Tran¹,

Baarsel²,

Washburn

et al. 2011

J Bacteriol

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“…6). Significant homologies to the RNA stabilizer protein Rop (Sozhamannan and Stitt, 1997) suggest that the enhancement role of CؒLlaI on LlaI restriction maybe to stabilize the llaI transcript. The involvement of CؒLlaI in inhibiting in vivo restriction at elevated temperature sheds new light on this age old phenomenon and now provides a basis for investigating its involvement in the temperature sensitivity of prokaryotic R/M systems.…”

Section: Discussionmentioning

confidence: 99%

Control of expression of LlaI restriction in Lactococcus lactis

O’Sullivan

Klaenhammer

1998

Molecular Microbiology

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SummaryThe plasmid encoded LlaI R/M system from Lactococcus lactis ssp. lactis consists of a bidomain methylase, with close evolutionary ties to type IIS methylases, and a trisubunit restriction complex. Both the methylase and restriction subunits are encoded on a polycistronic 6.9 kb operon. In this study, the 5Ј end of the llaI 6.9 kb transcript was determined by primer extension analysis to be 254 completely abolished any enhancement of restriction activity. These data provide molecular evidence for a mechanism on how the expression of a restriction system in a prokaryote can be drastically reduced during elevated growth temperatures, by a small regulatory protein.

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“…A pSC101-derived plasmid pHYD760 carrying rom þ was able to suppress increase in pACYC184 content and associated lethality in the nusG and rho mutants (Figure 4(D)). Plasmid pUCrop þ (a pUC19 derivative carrying rom þ ), 30 unlike pUC19 itself, yielded viable transformants in the nusG and rho strains (data not shown).…”

Section: Suppression Of Plasmid-associated Lethality By Rnase H1 or Rmentioning

confidence: 97%

Host Factor Titration by Chromosomal R-loops as a Mechanism for Runaway Plasmid Replication in Transcription Termination-defective Mutants of Escherichia coli

Harinarayanan

Gowrishankar

2003

Journal of Molecular Biology

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Effects on mRNA degradation by Escherichia coli transcription termination factor Rho and pBR322 copy number control protein rop

Cited by 25 publications

References 74 publications

Single-Gene Deletion Mutants of Escherichia coli with Altered Sensitivity to Bicyclomycin, an Inhibitor of Transcription Termination Factor Rho

Single-Gene Deletion Mutants of Escherichia coli with Altered Sensitivity to Bicyclomycin, an Inhibitor of Transcription Termination Factor Rho

Control of expression of LlaI restriction in Lactococcus lactis

Host Factor Titration by Chromosomal R-loops as a Mechanism for Runaway Plasmid Replication in Transcription Termination-defective Mutants of Escherichia coli

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