Molecular analysis of the recombination junctions of lambda bio transducing phages

To examine the mechanism of recombination involved in the formation of specialized transducing phage during the induction of bacteriophage lambda, we have determined the nucleotide sequences of the recombination junctions of lambda bio phages. The results indicate that abnormal excision takes place at many sites on both bacterial and phage genomes and that the recombination sites have short regions of homology (5-14 bp). Some of the sequences of the recombination sites were similar to the consensus sequences of DNA gyrase-cleavage sites and repetitive extragenic palindromic (REP) sequences. These results showed that abnormal excision is a type of illegitimate recombination. The possible involvement of DNA gyrase in this recombination is discussed.