Coupling of transcription and replication machineries in the λ DNA replication initiation: evidence for direct interaction of Escherichia coli RNA polymerase and the lambda O protein

Transcription proceeding downstream of the lambda phage replication origin was previously shown to support initial steps of the lambda primosome assembly in vitro and to regulate frequency and directionality of lambda DNA replication in vivo. In this report, the data are presented indicating that the RNA polymerase beta subunit makes a direct contact with the lambdaO protein, a replication initiator of lambda phage. These results suggest that the role of RNA polymerase during the initiation of lambda phage DNA replication may be more complex than solely influencing DNA topology. Results demonstrated in this study also show that gyrase supercoiling activity stimulates the formation of a complex between lambdaO and RNA polymerase, suggesting that the introduction of negative supercoils by DNA gyrase, besides lowering the energy required for DNA strand separation, may play an additional role in modeling protein–protein interactions at early steps of DNA replication initiation

Wprowadzenie

Wprowadzenie do nr 270 Acta Universitatis Lodziensis, Folia Oeconomic

Zarządzanie przedsięwzięciami budowlanymi w gospodarce polskiej: podstawy, procedury, przykłady

Zdjęcia w tekście: Jarosław Hałuszczak, Inwestycja II linii Metra w Warszawie, Inwestycja Złote Tarasy, Inwestycja Gemini Park, Inwestycja Tryton Park, Inwestycja GDDKiA, Inwestycja Autostrada Wielkopolska II – GDDKiA, Marcin Jurek, Inwestycje PGNiG SA, Elżbieta StrzeleckaProjekt okładki: Studio GKDS, www.gkds.pl; w tym zdjęcia: flickr.com, Wojciech Klemm – Inwestycja UNIBUD Sp. z o.o. w Łodzi, Photogenica.pl, Elżbieta Strzelecka – Politechnika Łódzka w ŁodziCelem publikacji jest przedstawienie wybranych zagadnień dotyczących zarządzania przedsięwzięciami budowlanymi na krajowym rynku budowlanym z uwzględnieniem aspektów technicznych, technologicznych, organizacyjnych, ekonomicznych, społecznych i środowiskowych. Podręcznik ten adresowany jest do studentów, menedżerów, praktyków związanych z budowlanymi projektami inwestycyjnymi. Zagadnienia poruszane w nim mogą stanowić ułatwienie w studiowaniu problematyki kierowania procesem inwestycyjnym, organizacji procesu inwestycyjnego, planowania i finansowania procesów inwestycyjnych, zarządzania ryzykiem, zarządzania jakością w procesach budowlanych, prawnych uwarunkowań procesów inwestycyjnych i ich wpływu na planowanie przestrzenne, zrównoważonego rozwoju w budownictwie

Coupling of transcription and replication machineries in λ DNA replication initiation: evidence for direct interaction of Escherichia coli RNA polymerase and the λO protein

Transcription proceeding downstream of the λ phage replication origin was previously shown to support initial steps of the λ primosome assembly in vitro and to regulate frequency and directionality of λ DNA replication in vivo. In this report, the data are presented indicating that the RNA polymerase β subunit makes a direct contact with the λO protein, a replication initiator of λ phage. These results suggest that the role of RNA polymerase during the initiation of λ phage DNA replication may be more complex than solely influencing DNA topology. Results demonstrated in this study also show that gyrase supercoiling activity stimulates the formation of a complex between λO and RNA polymerase, suggesting that the introduction of negative supercoils by DNA gyrase, besides lowering the energy required for DNA strand separation, may play an additional role in modeling protein–protein interactions at early steps of DNA replication initiation

Influence of the Escherichia coli oxyR gene function on λ prophage maintenance

In Escherichia coli hosts, hydrogen peroxide is one of the factors that may cause induction of λ prophage. Here, we demonstrate that H2O2-mediated λ prophage induction is significantly enhanced in the oxyR mutant host. The mRNA levels for cI gene expression were increased in a λ lysogen in the presence of H2O2. On the other hand, stimulation of the pM promoter by cI857 overproduced from a multicopy plasmid was decreased in the ΔoxyR mutant in the presence of H2O2 but not under normal growth conditions. The purified OxyR protein did bind specifically to the pM promoter region. This binding impaired efficiency of interaction of the cI protein with the OR3 site, while stimulating such a binding to OR2 and OR1 sites, in the regulatory region of the pM promoter. We propose that changes in cI gene expression, perhaps in combination with moderately induced SOS response, may be responsible for enhanced λ prophage induction by hydrogen peroxide in the oxyR mutant. Therefore, OxyR seems to be a factor stimulating λ prophage maintenance under conditions of oxidative stress. This proposal is discussed in the light of efficiency of induction of lambdoid prophages bearing genes coding for Shiga toxins

Suppression of the Escherichia coli dnaA46 mutation by changes in the activities of the pyruvate-acetate node links DNA replication regulation to central carbon metabolism.

To ensure faithful transmission of genetic material to progeny cells, DNA replication is tightly regulated, mainly at the initiation step. Escherichia coli cells regulate the frequency of initiation according to growth conditions. Results of the classical, as well as the latest studies, suggest that the DNA replication in E. coli starts at a predefined, constant cell volume per chromosome but the mechanisms coordinating DNA replication with cell growth are still not fully understood. Results of recent investigations have revealed a role of metabolic pathway proteins in the control of cell division and a direct link between metabolism and DNA replication has also been suggested both in Bacillus subtilis and E. coli cells. In this work we show that defects in the acetate overflow pathway suppress the temperature-sensitivity of a defective replication initiator-DnaA under acetogenic growth conditions. Transcriptomic and metabolic analyses imply that this suppression is correlated with pyruvate accumulation, resulting from alterations in the pyruvate dehydrogenase (PDH) activity. Consequently, deletion of genes encoding the pyruvate dehydrogenase subunits likewise resulted in suppression of the thermal-sensitive growth of the dnaA46 strain. We propose that the suppressor effect may be directly related to the PDH complex activity, providing a link between an enzyme of the central carbon metabolism and DNA replication