It has been observed that the class III bacteriophages Mu and D108 and the class II elements, Tn3, Tn1000, IS101 and Tn951, share the characteristics of replicatively transposing to random positions, producing 5 bp target site duplications and of containing the sequence 5$ sp prime$-PUCGAAAPu-3$ sp prime$ at bp 21 from their ends. These shared characteristics led to the hypothesis that these class III and class II elements evolved from a common ancestor transposon. Functional evidence which supports this hypothesis was obtained using the band retardation and in vivo transposition-mating assays. / Mu and D108 transposase proteins were shown to mediate the formation of specific protein-DNA complexes with the ends of Tn3 and IS101, but not with the ends of the IS102 element (class I) demonstrating the conservation of the first step in the transposition reaction between Mu, D108, Tn3 and IS101. / Transposition-mating assays with Mu transposase and the Tn3kan element demonstrated that recombination (rec A independent) products between Tn3kan-containing plasmids and the target (pOX38cam) were formed in the absence of Mu transposase, but their formation was stimulated 200-fold in the presence of Mu transposase protein. These transposition-mating products were resolved in rec $A sp+$ hosts, to generate resolution products suggestive of replicative transposition. Upon subsequent analysis, it was shown that the resolved products (pOX38cam::Tn3kan) had not been cleaved precisely at the Tn3kan element ends, but in the adjacent donor plasmid (pDV-cam) sequences. / Similar experiments with the IS101 element demonstrated that plasmids containing IS101 plus adjacent pSC101 sequences (bp 2233 to 2424), including a formerly unknown, but functional (bound by IHF) IHF site (bp 2238-2251), produced resolvable transposition-mating products in the presence of Mu transposase. These resolution products suggested that IS101 (like Tn3kan) was replicatively transposed. / The results presented provide functional evidence that links (evolutionarily) the class III transposable phages Mu and D108 and the class II elements Tn3 and IS101.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.70323 |
| Date | January 1992 |
| Creators | Cameron, Robin K. (Robin Katrine) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Microbiology and Immunology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001302281, proquestno: AAINN74799, Theses scanned by UMI/ProQuest. |
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