Tn7 Transposition

Bell, Stephen D (1992) Tn7 Transposition. PhD thesis, University of Glasgow.

Abstract

This project addressed a variety of aspects of the bacterial transposon Tn7. Firstly, the known sequence of the element was completed and the entire sequence compiled and presented. This was analysed with particular emphasis on the evolutionary implications of a series of directly repeated DNA motifs in the interior of Tn7 were discussed. These repeats were tested by gel retardation analysis for potential function as binding sites for Tn7 encoded proteins. These data are presented in Chapter 3. Chapter 4 deals with the construction of plasmids designed to co-ordinately over-express the TnsA, B, C and D proteins. These plasmids were tested for their ability to support transposition in vivo. One plasmid gave rise to a peculiar phenomenon in these assays,, a model is proposed for its action. A number of attempts to establish a Tn7 in vitro reaction are also described. Chapter 5 addresses the level of TnsD activity present in various cell extracts. An interaction between TnsD and one or more of TnsABC is detected and investigated and found be regulated by the hydrolysis of ATP. In the absence of ATP and magnesium ions a TnsABCD extract has no TnsD activity detectable by gel retardation assays, however in the presence of ATP and magnesium the same extract displays a detectable activity. Extracts containing TnsC and TnsD or TnsD on its own are not affected in this way. Chapter 6 presents data, initially identifying an IHF binding site in the attTn7 locus and localising the sequence determinants required for binding. IHF is demonstrated to induce a bend at the locus is demonstrated. The role of IHF in vivo in Tn7 transposition is investigated and it is demonstrated that transposition is reduced 6 fold in the absence of IHF. The potential role of IHF in the expression of the phoS gene, adjacent to attTn7 is also addressed.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: Dave Sherratt
• Keywords: Genetics
• Date of Award: 1992
• Depositing User: Enlighten Team
• Unique ID: glathesis:1992-75013
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 27 Sep 2019 14:36
• Last Modified: 27 Sep 2019 14:36
• URI: https://theses.gla.ac.uk/id/eprint/75013