THE M-GAMMA-DELTA-1 ELEMENT, A SMALL GAMMA-DELTA (TN1000) DERIVATIVE USEFUL FOR PLASMID MUTAGENESIS, ALLELE REPLACEMENT AND DNA SEQUENCING

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