Disease relevance of xylE

• The gene xylE, coding for xylose-proton symport in Escherichia coli, was cloned and its DNA sequence determined [1].
• Transcriptional fusion of the vgb gene promoter to the xylE reporter gene on the broad host range plasmid, pKD-49, was used to demonstrate that the vgb promoter can be expressed in other gram-negative organisms, including Pseudomonas, Azotobacter, and Rhizobium [2].
• A promoter probe transposon, Tn5099, containing a promoterless xylE gene, transposed in Streptomyces griseofuscus and S. fradiae, and transcriptional fusions were readily identified [3].
• The decay of the hybrid xylE transcript has been analyzed in E. coli and Erwinia, and in both strains this mRNA was among the most stable [4].
• This plasmid, p alpha omega, contains an expression cassette derived from bacteriophage T4 gene 32, into which we have inserted the coding sequence for the xylE enzyme (C2,3O) of the TOL plasmid pWWO [4].

High impact information on xylE

• The xylE gene was identified as a 1473-base pair open reading frame, located 373 base pairs downstream of malG, encoding a hydrophobic protein of Mr 53,607 [1].
• The cloning and DNA sequence of the gene xylE for xylose-proton symport in Escherichia coli K12 [1].
• It is proposed that the gene for the xylose-H+ symport system be called xylE [5].
• In vivo, the binding of MobL was studied by monitoring catechol 2,3-dioxygenase (xylE) activities driven by promoters of the divergently transcribed mobL and mobS genes [6].
• Transcripts initiating from cp3 were observed in RNA preparations from S. lividans containing the c gene deleted for cp1 and cp2, but gene fusions using DNA which should contain any putative promoting activity from this region transcriptionally fused to the xylE gene showed very low levels of expression of catechol 2,3 dioxygenase in S. lividans [7].

Chemical compound and disease context of xylE

• Catechol 2,3-oxygenase formed in E. coli carrying an xylE-containing plasmid is similar, or identical, to that formed in P. putida carrying the TOL plasmid [8].

Biological context of xylE

• A cosmid (pND320) bearing 42.5 kb of Escherichia coli chromosomal DNA, including the genes between xylE and ssb near minute 92 on the linkage map, was isolated by selection for complementation of a dnaB mutation [9].
• These included induction of xylose-specific operons (xylE, xylFGHR, and xylAB) regulated by XylR and the cyclic AMP-CRP system and repression of Mlc-regulated genes encoding glucose uptake (ptsHIcrr, ptsG) and mannose uptake (manXYZ) during growth on xylose [10].
• Two low-background promoter-probe vectors were constructed based on these cloning vectors with either lacZ or xylE as reporter genes; these were shown to report gene expression effectively in M. extorquens AM1 [11].
• Next, it is shown that inversion frequencies of xylE-encoding DNA, bracketed by Rci substrate sequences, may be modulated by changes in the 19-bp consensus sequences which are essential components of Rci substrate DNA [12].
• Transcriptional fusions of the promoter regions from rrnA and rrnB were constructed by utilizing the reporter molecule encoded by xylE and analyzed under various growth conditions, in both a wild-type background and an rrnBC mutant background [13].

Anatomical context of xylE

• Some derivatives contain promoterless trp-lacZ (TnMax11), xylE (TnMax10), phoA (TnMax6) or blaM (TnMax7, TnMax9) genes next to the IR, suitable for the generation of in vivo gene- and operon fusions to study gene regulation, protein export, or to determine the topology of proteins in bacterial membranes [14].

Associations of xylE with chemical compounds

• The xylE product, catechol 2,3-dioxygenase, was induced by m-xylene or m-methylbenzyl alcohol in the cells containing the fused operon when a 2.8-kilobase segment of the TOL plasmid was provided in trans [15].
• Utilization of D-ribose through D-xylose transporter [16].
• Insertion of the xylE gene within the BglII-ClaI fragment disrupted the induction of the 48-kilodalton polypeptide, GDPmannose dehydrogenase activity, and alg-5 complementing ability [17].

Other interactions of xylE

• The expression is based on the regulation of the tac promoter by the Lac repressor which was assayed with the xylE gene from Pseudomonas putida as a marker gene [18].

Analytical, diagnostic and therapeutic context of xylE

• When the xylE gene was maximally expressed, the induced enzyme constituted approx. 50% of total cellular protein as judged by laser densitometry following sodium dodecyl sulfate-polyacrylamide-gel electrophoresis [19].
• To investigate the control of these genes the three transcriptional promoters from this region were cloned by PCR and inserted into xylE promoter probe vectors [20].

References