The Uropathogenic Specific Protein Gene <i>usp</i> from <i>Escherichia coli</i> and <i>Salmonella bongori</i> is a Novel Member of the TyrR and H-NS Regulons

• Main Authors: Erik Rihtar, Darja Žgur Bertok, Zdravko Podlesek
• Format: Article
• Language: English
• Published: MDPI AG 2020-02-01
• Series: Microorganisms
• Subjects: <i>usp</i> promoter expression; tyrr regulon; h-ns nucleoid associated protein; <i>escherichia coli</i>; <i>salmonella bongori</i>; aromatic amino acids; temperature; urea
• Online Access: https://www.mdpi.com/2076-2607/8/3/330

The <i>Escherichia coli</i> PAI<i>usp</i> is a small pathogenicity island encoding <i>usp,</i> for the uropathogenic specific protein (Usp), a genotoxin and three associated downstream <i>imu1-3</i> genes that protect the producer against its own toxin. Bioinformatic analysis revealed the presence of the PAI<i>usp</i> also in publically available <i>Salmonella bongori</i> and <i>Salmonella enterica</i> subps. <i>salamae</i> genome sequences. PAI<i>usp</i> is in all examined sequences integrated within the <i>aroP-pdhR </i>chromosomal intergenic region. The focus of this work was identification of the <i>usp</i> promoter and regulatory elements controlling its activity. We show that, in both <i>E. coli</i> and <i>S. bongori</i>, the divergent TyrR regulated P3 promoter of the <i>aroP</i> gene, encoding an aromatic amino acid membrane transporter, drives <i>usp</i> transcription while H-NS acts antagonistically repressing expression. Our results show that the horizontally acquired PAI<i>usp</i> has integrated into the TyrR regulatory network and that environmental factors such as aromatic amino acids, temperature and urea induce <i>usp</i> expression.