Path of DNA within the Mu transpososome. Transposase interactions bridging two Mu ends and the enhancer trap five DNA supercoils.
The phage Mu transpososome is assembled by interactions of transposase subunits with the left (L) and right (R) ends of Mu and an enhancer (E) located in between. A metastable three-site complex LER progresses into a more stable type 0 complex in which a tetrameric transposase is poised for DNA cleavage. "Difference topology" has revealed five trapped negative supercoils within type 0, three contributed by crossings of E with L and R, and two by crossings of L with R. This is the most complex DNA arrangement seen to date within a recombination synapse. Contrary to the prevailing notion, the enhancer appears not to be released immediately following type 0 assembly. Difference topology provides a simple method for determining the ordered sequestration of DNA segments within nucleoprotein assemblies.
Pathania
Shailja
S
Section of Molecular Genetics and Microbiology and Institute of Cellular and Molecular Biology, University of Texas at Austin, 78712, USA.
Jayaram
Makkuni
M
Harshey
Rasika M
RM
D010583:Bacteriophage mu / Q000235:genetics* / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D001681:Biological Assay; D004251:DNA Transposable Elements / Q000235:genetics*; D004278:DNA, Superhelical / Q000235:genetics* / Q000378:metabolism; D004279:DNA, Viral / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D015967:Gene Expression Regulation, Viral / Q000235:genetics; D019426:Integrases / Q000235:genetics / Q000378:metabolism; D015394:Molecular Structure; D010957:Plasmids / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D011995:Recombination, Genetic / Q000235:genetics; D019895:Transposases / Q000235:genetics*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism
D004251:DNA Transposable Elements; D004278:DNA, Superhelical; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D014764:Viral Proteins; C045073:Cre recombinase; D019426:Integrases; D019895:Transposases