Multiple homeostatic mechanisms in the control of P1 plasmid replication

Das, Nilangshu; Valjavec-Gratian, Majda; Basuray, Ashish N.; Fekete, Richard A.; Papp, Péter; Paulsson, Johan O.; Chattoraj, Dhruba K.

doi:10.1073/pnas.0409790102

Cited by 44 publications

(40 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Including the entire ig2 and rctA in the test plasmid would indicate the contribution of RctB limitation in controlling the copy number of oriCII VC replicon. In any event, initiator limitation by autoregulation alone cannot control replication: the basal level of initiator increases following replication due to the increase in the number of initiator genes (5). There ought to be other mechanisms to reduce initiator synthesis or availability or origin availability following replication to prevent runaway replication.…”

Section: Discussionmentioning

confidence: 99%

“…RctB was supplied either from an inducible source, pTVC11, or constitutively from pTVC13 (a pET28a derivative, but the cells did not have a source of T7 polymerase) when rctA was also present in the same cell. cation or cell growth (5). To the extent that it was overproduced, RctB was not found to be detrimental to E. coli growth (Fig.…”

Section: Vol 187 2005 Multipartite Regulation Of Rctb V Cholerae 7171mentioning

confidence: 99%

See 1 more Smart Citation

Multipartite Regulation ofrctB, the Replication Initiator Gene ofVibrio choleraeChromosome II

et al. 2005

Self Cite

View full text Add to dashboard Cite

Replication initiator proteins in bacteria not only allow DNA replication but also often regulate the rate of replication initiation as well. The regulation is mediated by limiting the synthesis or availability of initiator proteins. The applicability of this principle is demonstrated here for RctB, the replication initiator for the smaller of the two chromosomes of Vibrio cholerae. A strong promoter for the rctB gene named rctBp was identified and found to be autoregulated in Escherichia coli. Promoter activity was lower in V. cholerae than in E. coli, and a part of this reduction is likely to be due to autorepression. Sequences upstream of rctBp, implicated earlier in replication control, enhanced the repression. The action of the upstream sequences required that they be present in cis, implying long-range interactions in the control of the promoter activity. A second gene specific for chromosome II replication, rctA, reduced rctB translation, most likely by antisense RNA control. Finally, optimal rctBp activity was found to be dependent on Dam. Increasing RctB in trans increased the copy number of a miniplasmid carrying oriCII VC , implying that RctB can be rate limiting for chromosome II replication. The multiple modes of control on RctB are expected to reduce fluctuations in the initiator concentration and thereby help maintain chromosome copy number homeostasis.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Vol 187 2005 Multipartite Regulation Of Rctb V Cholerae 7171mentioning

confidence: 99%

Multipartite Regulation ofrctB, the Replication Initiator Gene ofVibrio choleraeChromosome II

et al. 2005

Self Cite

View full text Add to dashboard Cite

show abstract

“…In B. subtilis, DnaA boxes are probably also involved in the regulation of chromosome replication; the oriC region is also flanked by several clusters of DnaA boxes (32,42), and strong incompatibility was observed between plasmid and chromosomal oriC regions when an additional cluster of DnaA boxes was delivered on a plasmid (55). Chromosomal replication control in Streptomyces and B. subtilis has similarities to replication control of low-copy-number plasmids, such as P1, RK2, pSC101 P1, RK2, pSC101, and F, which harbor binding sites for initiator protein (iterons) which are found not only in the origin but also outside ori (9,46). When deleted and cloned in trans, these sites increase and reduce plasmid copy number, respectively.…”

Section: Discussionmentioning

confidence: 99%

Cluster of DnaA Boxes Involved in Regulation of Streptomyces Chromosome Replication: from In Silico to In Vivo Studies

et al. 2006

View full text Add to dashboard Cite

In Streptomyces coelicolor, replication is initiated by the DnaA protein in the centrally located oriC region and proceeds bidirectionally until the replication forks reach the ends of the linear chromosome. We identified three clusters of DnaA boxes (H69, H24, and D78) which are in a relatively short segment of the chromosome centered on the oriC region. Of the clusters analyzed, D78 exhibited the highest affinity for the DnaA protein; the affinity of DnaA for the D78 cluster was about eightfold higher than the affinity for oriC. The high-affinity DnaA boxes appear to be involved in the control of chromosome replication. Deletion of D78 resulted in more frequent chromosome replication (an elevated ratio of origins to chromosome ends was observed) and activated aerial mycelium formation, leading to earlier colony maturation. In contrast, extra copies of D78 (delivered on a plasmid) caused slow colony growth, presumably because of a reduction in the frequency of initiation of chromosome replication. This suggests that the number of high-affinity DnaA boxes is relatively constant in hyphal compartments and that deletion of D78 therefore permits an increased copy number of either the chromosomal origin region or a plasmid harboring the D78 cluster. This system conceivably influences the timing of decisions to initiate aerial mycelial formation and sporulation.

show abstract

“…We have argued that controlling replication initiation frequency by initiator autoregulation and titration cannot be sufficient because it can only dampen initiator increase after duplication of the initiator gene upon passage of the replication fork (34). To prevent reinitiation, the initiator level must decrease as a consequence of replication.…”

Section: Discussionmentioning

confidence: 99%

Transcriptional inactivation of a regulatory site for replication of Vibrio cholerae chromosome II

Venkova-Canova¹,

Srivastava²,

Chattoraj³

2006

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

View full text Add to dashboard Cite

The oriCII region that includes the initiator gene, rctB, can function as a plasmid in E. coli. Here we show that RctB suffices for the oriCII-based plasmid replication, and rctA in cis or trans reduces the plasmid copy number, thereby serving as a negative regulator. The inhibitory activity could be overcome by increasing the concentration of RctB, suggesting that rctA titrates the initiator. Purified RctB bound to a DNA fragment carrying rctA, confirming that the two can interact. Although rctA apparently works as a titrating site, it is nonetheless transcribed. We find that the transcription attenuates the inhibitory activity of the gene, presumably by interfering with RctB binding. RctB, in turn, repressed the rctA promoter and, thereby, could control its own titration by modulating the transcription of rctA. This control circuit appears to be a putative novel mechanism for homeostasis of initiator availability.O ur knowledge of DNA replication control in bacteria comes largely from studying the chromosome and plasmids of Escherichia coli (1, 2). In general, controlling proteins that initiate replication, initiator proteins, seems to be the central mechanism to regulate replication. A variety of mechanisms have been found to control the initiator.Transcriptional autoregulation of the initiator gene is common in plasmids with iterated initiator-binding sites (iterons), where the initiator serves as the repressor of its own synthesis (3). The E. coli initiator, DnaA, also is autoregulated (4). In addition, the dnaA promoter is inactivated by sequestration to the cell membrane for approximately one-third of the cell generation (5). More traditional modes of transcriptional control using repressors and activators also have been found in phage and plasmid RK2 (6, 7).Initiator translation is regulated by antisense RNAs in a variety of plasmids, the classic examples being plasmids R1 and pT181 (8, 9). The antisense RNA either blocks the ribosomebinding site of the initiator gene directly or of a regulatory peptide for the initiator gene (10).Most other mechanisms operate posttranslationally either by titrating or inactivating the initiator protein. In E. coli, there are Ϸ300 DnaA-binding sites scattered all over the chromosome (11,12). Titration of the initiator to these sites is believed to reduce availability of the protein after replication initiation, because new sites are created during replication elongation.Initiator inactivation is the most widely used mechanism to prevent premature replication reinitiation. The pT181 initiator is inactivated by covalent modification at the end of one round of replication (13). E. coli DnaA is converted from an active ATP bound form to an inactive ADP form after replication (14-16). A similar mechanism also operates in Bacillus subtilis (17). The initiators of iteron-carrying plasmids are inactivated by dimerization, the active form being monomers (18). Dimerization not only reduces monomer concentration, the dimers also participate in inactivating origins (19)(20)(21). Euk...

show abstract

Multiple homeostatic mechanisms in the control of P1 plasmid replication

Cited by 44 publications

References 44 publications

Multipartite Regulation ofrctB, the Replication Initiator Gene ofVibrio choleraeChromosome II

Multipartite Regulation ofrctB, the Replication Initiator Gene ofVibrio choleraeChromosome II

Cluster of DnaA Boxes Involved in Regulation of Streptomyces Chromosome Replication: from In Silico to In Vivo Studies

Transcriptional inactivation of a regulatory site for replication of Vibrio cholerae chromosome II

Contact Info

Product

Resources

About