Exploring the functional role of the bacterial protein SeqA and co--?occurring genome stability systems in TnsE--?mediated Tn7 transposition using the E. coli model system
Transposon Tn7, is unique among transposons for both its target specificity and selectivity. One of its target selection pathways, mediated by the protein TnsE, has been found to allow Tn7 to preferentially transpose into mobile plasmids despite there only composing approximately 1% of the bacterial genome. Prior research in the Peters laboratory revealed both a physical interaction between TnsE and the bacterial protein SeqA as well as a functional role of the TnsE--?SeqA interaction in TnsE--?mediated transposition. Based on this work a model was developed, whereby SeqA occludes TnsE’s access to the replicating chromosome. An unrelated study from another group found that the genes yfbV, metJ, holD, mutH, and matP co--?occurred with seqA in genomes with an ancestral dam gene. In this project, an in vivo Tn7 transposition assay was used to investigate the role of the SeqA--?TnsE interaction in the TnsE pathway of Tn7 transposition. The same transposition assay was also used on the co--?occuring set of bacterial proteins in order to identify a possible association with their gene products and TnsE--?mediated transposition. The Tn7 transposition events were then mapped using two complementary assays. The results suggest that in the absence of SeqA, TnsE--?mediated Tn7 transposition increases significantly and that a much higher percentage of the insertions occur into the chromosome in a DseqA background, thus supporting our model. The results for the other proteins were much less clear, with the only significant change in TnsE--?mediated transposition frequency occurring in the DmetJ mutant, where no successful Tn7 transpositions were observed within the detection of our assay.
Biological sciences honors program; mobile genetic elements; Tn7; Escherichia coli; transposition
B.A. of Biological Sciences
Bachelor of Arts
dissertation or thesis