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tRNA genes and pathogenicity islands: influence on virulence and metabolic properties of uropathogenic Escherichia coli
Author(s) -
Ritter Angelika,
Blum Gabriele,
Emödy Levente,
Kerenyi Monika,
Böck August,
Neuhieri Bernhard,
Rabsch Wolfgang,
Scheutz Flemming,
Hacker Jörg
Publication year - 1995
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1995.mmi_17010109.x
Subject(s) - biology , virulence , pathogenicity island , transfer rna , gene , escherichia coli , selenocysteine , mutant , genetics , fimbria , microbiology and biotechnology , rna , biochemistry , enzyme , cysteine
The uropathogenic Escherichia coli strain 536 (O6:K15:H31) carries two unstable DNA regions on its chromosome which were termed pathogenicity islands (Pais). Both pathogenicity islands, Pai I and Pai II, are incorporated into tRNA specific loci: Pai I is located in the tRNA gene for selenocysteine ( selC ), and Pai II is integrated in the leucine‐specific tRNA locus leuX . Mutant strain 536−21 has lost the two pathogenicity islands together with the intact tRNA genes. While 536 is a virulent strain, 536−21 has lost a number of properties, including in vivo virulence. In previous publications we reported that the genes coding for two haemolysins ( hly I, hly II) and P‐related fimbria ( prf ) are located on the Pais. In this paper, we demonstrate that the expression of other gene products influencing metabolic properties in addition to in vivo virulence are strongly dependent on the intact tRNA loci selC and leuX . In order to determine the influence of the two tRNAs on the expression of these properties, the genes seIC and leuX were cloned from the genome of strain 536 and then introduced into the mutant 536−21. Our results clearly show that the selenocysteine‐specific tRNA (tRNA Sec ) directly influences the ability of the bacteria to grow under anaerobic conditions, because selenocysteine is part of the enzyme formate dehydrogenase (FDH) which is involved in mixed acid fermentation. The rare leucine‐specific tRNA 5 Leu , encoded by leuX , influences a number of properties including type 1 fimbria production, flagellation and motility, production of enterobactin and serum resistance, and is also necessary for full in vivo virulence. While the tRNA Sec is directly involved in the production of FDHs, the leuX specific tRNA 5 Leu appears to influence the expression of various factors through specific transcriptional or translational control mechanisms.