Naslov
The induction of Escherichia coli aidB gene in Salmonella typhimurium

Autori
Bačun-Družina, Višnja ; Džidić, Senka ; Perić, Nataša ; Ivančić, Mirela ; Franekić Čolić, Jasna

Izvornik
Periodicum biologorum (1849-0964) 105 (2003), 3; 257-262

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Escherichia coli; Salmonella typhimurium; adaptive response; aidB gene; aidB-lacZ induction

Sažetak
In Escherichia coli, the main response specific for alkylation damage has been called the adaptive response. It is a set of genes composed of the ada, alkA, alkB, and aidB genes. The AidB protein is involved in a detoxification pathway for N-methil-N^, -nitro-N-nitrosoguanidine (MNNG), although its function is still unclear. Adaptive reponse is not detectable in the closely related Salmonella typhimurium. It has been suggested that the lack of this reponse is due to the low ability of methylated Ada_ST to act as a transcriptional acitvator. We analyzed the induction of E. coli aidB gene i S. typhimurium applying aidB-lacZ operon fusion. The activation of aidB promoter was monitored in ada-dependent conditions as well as ada-independent induction during oxygen-limiting or acidic conditions. Material and Methods: The induction of E. coli aidB gene was monitored by assaying beta-galactosidase activity in extract obtained from cells containing operon fusion of Mu dl(bla, lac) to aidB. Results: Methylating agents MMNG and methyl methanesulfonate (MMS) induced ada-dependent transcription of aidB gene in S. typhimurium at the same level as in E. coli. Alkylating agents N-methyl-N-nitrosourea (MNU) and ethyl methanesulfonate (EMS) did not induce significant expression of aidB gene. Decreasing extracellular pH as well as semianaerobiosis, ada-independent induction, increased aidB gene expression in S. typhimurium. Conclusions: MNNG and MMS induction of E. coli aidB gene in S. typhimurium through ada-dependent mode indicates the possibility that methylated Ada_ST acts as a transcriptional activator.

Izvorni jezik
Engleski

Znanstvena područja
Biotehnologija

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