FIG. 1.

The presence of a single Tn917 insertion within the bee locus in mutant strain P101D12 was confirmed by Southern analysis using a Tn917-specific probe (a 1.9-kb internal region of Tn917 containing two HindIII restriction sites) as described previously (10). (A) Genomic DNA obtained from wild-type strain E99 and mutant P101D12 was restricted with HindIII (lanes 1 and 2) and EcoRI (lanes 4 and 5). (B) Southern hybridization was performed subsequently with the Tn917 probe obtained by using primers Tn917-1 and Tn917-2. The HindIII (lane 3)- and EcoRI (lane 6)-restricted plasmid pTV1-OK was used as the positive control. For size reference, a 1-kb DNA ladder (New England Biolabs, Beverly, MA) was used (lane M).