Dataset Information

Characterization of the F-plasmid conjugative transfer gene traU.

ABSTRACT: We characterized the traU gene of the Escherichia coli K-12 conjugative plasmid F. Plasmids carrying segments of the F transfer operon were tested for their capacity to complement F lac traU526. The protein products of TraU+ clones were identified, and the nucleotide sequence of traU was determined. traU mapped between traW and trbC. It encodes a 330-amino-acid, Mr36,786 polypeptide that is processed. Ethanol caused accumulation of a precursor polypeptide; removal of ethanol permitted processing of the protein to occur. Because F lac traU526 strains appear to be resistant to F-pilus-specific phages, traU has been considered an F-pilus assembly gene. However, electron microscopic analysis indicated that the traU526 amber mutation caused only a 50% reduction in F-piliation. Since F lac traU526 strains also retain considerable transfer proficiency, new traU mutations were constructed by replacing a segment of traU with a kanamycin resistance gene. Introduction of these mutations into a transfer-proficient plasmid caused a drastic reduction in transfer proficiency, but pilus filaments remained visible at approximately 20% of the wild-type frequency. Like traU526 strains, such mutants were unable to plaque F-pilus-specific phages but exhibited a slight sensitivity on spot tests. Complementation with a TraU+ plasmid restored the wild-type transfer and phage sensitivity phenotypes. Thus, an intact traU product appears to be more essential to conjugal DNA transfer than to assembly of pilus filaments.

SUBMITTER: Moore D

PROVIDER: S-EPMC213250 | biostudies-other | 1990 Aug

REPOSITORIES: biostudies-other

ACCESS DATA

Publications

Characterization of the F-plasmid conjugative transfer gene traU.

Moore D D Maneewannakul K K Maneewannakul S S Wu J H JH Ippen-Ihler K K Bradley D E DE

Journal of bacteriology 19900801 8

We characterized the traU gene of the Escherichia coli K-12 conjugative plasmid F. Plasmids carrying segments of the F transfer operon were tested for their capacity to complement F lac traU526. The protein products of TraU+ clones were identified, and the nucleotide sequence of traU was determined. traU mapped between traW and trbC. It encodes a 330-amino-acid, Mr36,786 polypeptide that is processed. Ethanol caused accumulation of a precursor polypeptide; removal of ethanol permitted processing ...[more]

PMID: 2198250

Similar Datasets

Project description:BACKGROUND: Our observation that in the Mexican Salmonella Typhimurium population none of the ST19 and ST213 strains harbored both the Salmonella virulence plasmid (pSTV) and the prevalent IncA/C plasmid (pA/C) led us to hypothesize that restriction to horizontal transfer of these plasmids existed. We designed a conjugation scheme using ST213 strain YU39 as donor of the blaCMY-2 gene (conferring resistance to ceftriaxone; CRO) carried by pA/C, and two E. coli lab strains (DH5? and HB101) and two Typhimurium ST19 strains (SO1 and LT2) carrying pSTV as recipients. The aim of this study was to determine if the genetic background of the different recipient strains affected the transfer frequencies of pA/C. RESULTS: YU39 was able to transfer CRO resistance, via a novel conjugative mechanism, to all the recipient strains although at low frequencies (10-7 to 10-10). The presence of pSTV in the recipients had little effect on the conjugation frequency. The analysis of the transconjugants showed that three different phenomena were occurring associated to the transfer of blaCMY-2: 1) the co-integration of pA/C and pX1; 2) the transposition of the CMY region from pA/C to pX1; or 3) the rearrangement of pA/C. In addition, the co-lateral mobilization of a small (5 kb) ColE1-like plasmid was observed. The transconjugant plasmids involving pX1 re-arrangements (either via co-integration or ISEcp1-mediated transposition) obtained the capacity to conjugate at very high levels, similar to those found for pX1 (10-1). Two versions of the region containing blaCMY-2 were found to transpose to pX1: the large version was inserted into an intergenic region located where the "genetic load" operons are frequently inserted into pX1, while the short version was inserted into the stbDE operon involved in plasmid addiction system. This is the first study to report the acquisition of an extended spectrum cephalosporin (ESC)-resistance gene by an IncX1 plasmid. CONCLUSIONS: We showed that the transfer of the YU39 blaCMY-2 gene harbored on a non- conjugative pA/C requires the machinery of a highly conjugative pX1 plasmid. Our experiments demonstrate the complex interactions a single strain can exploit to contend with the challenge of horizontal transfer and antibiotic selective pressure.

Dataset Information

Characterization of the F-plasmid conjugative transfer gene traU.

Publications

Characterization of the F-plasmid conjugative transfer gene traU.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets