An inverted repeat in the Tn21 integron determines the production of stem-loop DNA

A 580-bp-long stem-loop DNA (sl-DNA) molecule was produced by a recombinant plasmid containing complete int and aadA genes from the transposon Tn21 cloned in the vector pUC18. A 50-bp-long inverted repeat found near the int gene stop codon could be involved in the generation of the sl-DNA molecule. Cloning of the dhfrII gene between the plasmid replication origin and this IR produced an extended sl-DNA including the dhfrII gene. Tn21 recombination hot spot 2 was also able to direct the production of sl-DNA. © 1996 Academic Press, Inc.This work was supported by Grants SAL-0241 and PB93-0368 from the CICYT, Spain.Peer Reviewe