Tetracycline resistance transposon Tn1721: recA-dependent gene amplification and expression of tetracycline resistance

Wiebauer, Karin; Schraml, S; Shales, Stuart W.; Schmitt, Rüdiger

doi:10.1128/jb.147.3.851-859.1981

Cited by 35 publications

(21 citation statements)

References 35 publications

(76 reference statements)

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“…The tandem duplication of genes provides a mechanism for amplifying gene expression. Analysis of bacteria selected for increased antibiotic resistance has shown that they often contain tandem duplicated copies of an antibiotic resistance gene that is present in low copy number in unselected bacteria (Wiebauer et al, 1981). By analogy with bacteria, the tandem repetition of the MATE genes could provide a mechanism for increasing the resistance of plants to toxic compounds in the soil.…”

Section: Discussionmentioning

confidence: 99%

Arabidopsis ALF5, a Multidrug Efflux Transporter Gene Family Member, Confers Resistance to Toxins

Diener¹

2001

The Plant Cell Online

111

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The Arabidopsis genome contains many gene families that are not found in the animal kingdom. One of these is the multidrug and toxic compound extrusion (MATE) family, which has homology with bacterial efflux transporters. Arabidopsis has at least 54 members of this family, which often are found in tandem repeats. Analysis of ALF5, one member of this Arabidopsis family, suggests that its function is required for protection of the roots from inhibitory compounds. Loss of ALF5 function results in the sensitivity of the root to a number of compounds, including a contaminant of commercial agar. Moreover, expression of the Arabidopsis ALF5 cDNA in yeast confers resistance to tetramethylammonium. These phenotypes are consistent with a role for ALF5 as an efflux transporter. Both transcriptional and translational fusions of ALF5 to the beta-glucuronidase reporter gene show that ALF5 is expressed strongly in the root epidermis, a tissue in direct contact with the external environment. The distinct requirement for ALF5 function is remarkable because of the large number of MATE gene family members in Arabidopsis, one of which is adjacent to ALF5 and 83% identical to ALF5 at the amino acid level.

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Section: Discussionmentioning

confidence: 99%

Arabidopsis ALF5, a Multidrug Efflux Transporter Gene Family Member, Confers Resistance to Toxins

Diener¹

2001

The Plant Cell Online

111

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“…Tnl 724 is a derivative of Tn) 721 with a chloramphenicol resistance determinant encoded on a 3.3-kb HindIII fragment (from R plasmid Sa; 9, 28), which was ligated into the single HindIII site of Tn)722 (24). Tn1725 was derived from Tnl724 by the recA-dependent elimination of the tet region (29), resulting in a modified Tn1722 that carries a chloramphenicol resistance marker (P. Rogowsky, unpublished data).…”

Section: Methodsmentioning

confidence: 99%

“…The majority of clones thus selected contained insertions of Tnl725 into pJOE398. Plasmids from each clone were separately isolated by the rapid isolation method (29) and transformed into strain HB11. The number of chloramphenicol-resistant transformants ranged between 0 and 200.…”

Section: Transformation and In Vitro Generation Of Deletionsmentioning

confidence: 99%

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Tn1721-encoded tetracycline resistance: mapping of structural and regulatory genes mediating resistance

Altenbuchner¹,

Schmid²,

Schmitt³

1983

J Bacteriol

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The genes encoding inducible tetracycline resistance in Tn1721 were located in a 2.1-kilobase portion of the transposon. Using deletions and insertions, we mapped and characterized two tet genes by their mutant phenotypes. Two tetracycline-inducible polypeptides synthesized in minicells were assigned to the tet genes. The polarity of the tet genes was determined by employing a deletion and a gene fusion which altered the carboxy termini of the polypeptides. The gene responsible for resistance (tetA) encompasses 1,250 base pairs and encodes a membrane-bound protein with an apparent molecular weight of 34,000. The second gene (tetR) encompasses at least 650 base pairs and encodes a soluble 26,000-dalton protein, identified by complementation analysis as the repressor. The two adjacent genes have opposite transcriptional polarity, suggesting that the sites controlling their expression are located in the intercistronic region between tetA and tetR.

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“…In TB90, mutagenesis can be induced with the addition of L-(+)-arabinose (Sigma; Methods S1; Table S6). The TB90 strain lacks the recA gene, to reduce recombination and gene loss among duplicate TEM-1 copies as well as to minimize the incidence of higher order amplifications (Reams et al 2010), which have already been studied (Wiebauer et al 1981;Goldberg and Mekalanos 1986;Reams et al 2012). For all E. coli cultures, we used LB medium (Becton-Dickinson).…”

Section: Bacterial Strains and Mediummentioning

confidence: 99%

Increased Gene Dosage Plays a Predominant Role in the Initial Stages of Evolution of Duplicate Tem-1 Beta Lactamase Genes

2014

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Gene duplication is important in evolution, because it provides new raw material for evolutionary adaptations. Several existing hypotheses about the causes of duplicate retention and diversification differ in their emphasis on gene dosage, subfunctionalization, and neofunctionalization. Little experimental data exist on the relative importance of gene expression changes and changes in coding regions for the evolution of duplicate genes. Furthermore, we do not know how strongly the environment could affect this importance. To address these questions, we performed evolution experiments with the TEM-1 beta lactamase gene in Escherichia coli to study the initial stages of duplicate gene evolution in the laboratory. We mimicked tandem duplication by inserting two copies of the TEM-1 gene on the same plasmid. We then subjected these copies to repeated cycles of mutagenesis and selection in various environments that contained antibiotics in different combinations and concentrations. Our experiments showed that gene dosage is the most important factor in the initial stages of duplicate gene evolution, and overshadows the importance of point mutations in the coding region.

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Tetracycline resistance transposon Tn1721: recA-dependent gene amplification and expression of tetracycline resistance

Cited by 35 publications

References 35 publications

Arabidopsis ALF5, a Multidrug Efflux Transporter Gene Family Member, Confers Resistance to Toxins

Arabidopsis ALF5, a Multidrug Efflux Transporter Gene Family Member, Confers Resistance to Toxins

Tn1721-encoded tetracycline resistance: mapping of structural and regulatory genes mediating resistance

Increased Gene Dosage Plays a Predominant Role in the Initial Stages of Evolution of Duplicate Tem-1 Beta Lactamase Genes

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