The mγδ-1 element, a small γδ (Tn1000) derivative useful for plasmid mutagenesis, allele replacement and DNA sequencing

Transposon γδ (Tn1000), a 6-kb member of the Tn3 family, is widely used for plasmid mutagenesis. A 1.8-kb derivative of γδ was constructed that contains the kan gene from Tn5 and the resolution (res) site from γδ cloned between 40-bp inverted repeats of γδ's delta (δ) end. This element, named mγδ-1, lacks the genes encoding transposase and resolvase, and therefore depends on its host to supply transposition and resolution functions. Thus, in strains lacking γδ, mγδ-1 will not transpose. The mγδ-1 element is shown to be useful for mutagenesis of plasmids, DNA sequencing, and allele replacement (in Streptomyces avermitilis).