RESEARCH ARTICLE


Identification of Salmonella enterica Serovar Typhi DNA Fragments with Transcriptional Activity Under Different Growth Conditions



Daniele Saverino*, 1, Jennifer McDermott2, McDermott Ferrari3, Marta Terrile4, 5, Gabriella Piatti3
1 Università Degli Studi di Genova, Dipartimento di Medicina Sperimentale, DiMeS, Sezione di Anatomia Umana, Italy
2 Advanced Biotechnology Center, ABC, Genova, Italy
3 Università degli Studi di Genova, Dipartimento Interdisciplinare di Scienze Speialistiche, Chirurgiche, di Microbiologia e dei Trapianti d’Organo (DISCMIT), Sezione di Microbiologia “C. A. Romanzi”, Italy
4 Laboratorio di Oncologia Sperimentale F, Istituto Nazionale per la Ricerca sul Cancro, IST, Genova, Italy
5 Laboratorio di Oncologia Sperimentale F, Istituto Nazionale per la Ricerca sul Cancro, IST, Genova, Italy


© 2008 Saverino et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Università Degli Studi di Genova, Dipartimento di Medicina Sperimentale, DiMeS, Sezione di Anatomia Umana, Di.Me.S., Via De Toni, 14, 16132 Genova, Italy. E-mail: daniele.saverino@unige.it


Abstract

Salmonella enterica serovar Typhi is a human pathogenic microorganism with a very complex infective cycle, involving the transit of bacteria across different microenvironments; to optimize the performance of attenuated Salmonella strains suitable as live carriers of heterologous antigens, fine tuning of wild type bacteria gene expression is essential.

Several DNA fragments were obtained from a Salmonella enterica serovar Typhi (vi+, fim+) blood isolate and 18 clones were selected according to the dimension of the insert (range <0.2-1.6 kb). These fragments showed a transcriptional activity in a promoterless vector cloned in Escherichia coli background, according to homogeneous parameters. The results obtained provide an insight about signals mediating gene activation in vivo, particularly in the microenvironments known to exist during the infectious process, even if the fragments are not promoters sequences. Finally, the functional characterization of several fragments showed that they possessed an efficient and homogeneous transcriptional activity, worth to be further investigated.

Keywords: Promoter regions, Salmonella enterica serovar Typhi, gene expression.