Disease relevance of mobA

• In Escherichia coli, in the presence of a chromosomally integrated derivative of the broad-host-range IncP plasmid, RP4, TnpZ was able to promote plasmid mobilization in cis and was able to function in trans to enable the mobilization of a co-resident plasmid carrying an RSA site [1].
• The 6.3 kb Clostridium perfringens transposon Tn4451 encodes a 50 kDa protein, TnpZ, which has amino acid sequence similarity to a group of plasmid mobilization and recombination proteins that comprise the Mob/Pre family [1].
• To test the hypothesis that the putative oriT site in pIP501 played a role in conjugal transfer, we conducted plasmid mobilization studies in Enterococcus faecalis [2].
• Thus, plasmid mobilization promoted by pVA1702 (pIP501) works in a fashion similar to that known to occur widely in gram-negative bacteria [2].
• Plasmid pIPO2 had a broad IncQ plasmid mobilization and self-transfer range among the alpha, beta, and gamma subclasses of the Proteobacteria but did not show productive transfer to gram-positive bacteria [3].

High impact information on mobA

• Gene walking analysis of the upstream region of mobA revealed an open reading frame (mobR) that encodes a transcriptional regulator of the MarR family [4].
• A primer extension experiment was performed to determine the transcription start site for mobA and identified it at 83 bp upstream of the mobA start codon, accompanied by a typical sigma(70)-type promoter [4].
• The operator site is located between the start codon and the promoter region for mobA, suggesting that MobR functions as a transcriptional repressor for mobA expression [4].
• Here, we report that MobR negatively regulates the expression of mobA, and that the repression is relieved by binding of 3-hydroxybenzoate, the substrate for MobA [4].
• In addition to the requirement for high affinity binding to oriT, efficient in vitro nicking and in vivo plasmid mobilization requires a pyrimidine immediately 5' of the nick site [5].

Biological context of mobA

• Identification and characterization of RP1 Tra1 cistrons involved in pilus function and plasmid mobilization [6].
• Since the deleted fragments correspond to the mobility region of ColE1, the cAMP dependency of the gene expression should be somehow related to the plasmid mobilization function [7].
• The ORF-2 encoded protein showed 31 to 35% sequence homology to proteins identified to have a role in plasmid mobilization [8].
• Molecular mechanism of Ti plasmid mobilization by R plasmids: isolation of Ti plasmids with transposon-insertions in Agrobacterium tumefaciens [9].
• The third plasmid from the set could not be correlated with a drug-resistance phenotype, but does appear to play a crucial role in plasmid mobilization [10].

Associations of mobA with chemical compounds

• Analysis of exconjugant cells revealed that plasmid mobilization occurs via cointegrate formation involving transposition of IS21 [11].

Analytical, diagnostic and therapeutic context of mobA

• Site-directed mutagenesis of two bases within the RSA site resulted in a significant reduction in mobilization frequency, demonstrating that the RSA site is required for efficient plasmid mobilization [1].
• An analogous series of vectors that are defective in their plasmid-mobilization function, and that exhibit a degree of biological containment comparable to that of current Escherichia coli vector plasmids, are also described [12].
• Transformation using artificial competence, high-voltage electroporation, and plasmid mobilization experiments with the mobilizing plasmid RP4, failed to ascertain the 83 kb plasmid was responsible for Ag(+)-resistance [13].

References