AN IN-SILICO EVALUATION OF TN916 AS A TOOL FOR GENERALIZED MUTAGENESIS IN HAEMOPHILUS-INFLUENZAE RD

The transposon Tn916 was evaluated as a tool for generalized mutagenes is of the genome of Haemophilus influenzae. This was achieved in silic o by searching the genome sequence of H. influenzae Rd for the publish ed Tn916 target site consensus sequence 5' TT/ATTTT(N)(6)AAAAA/TA. Thi s search identified 16 putative target sites. In subsequent experiment s, integration of Tn916 did not occur at any of these sites. Using the nucleotide sequences of these observed integration sites, a new conse nsus sequence, 5' TTTTT(N)(x)AAAAA (4 less than or equal to x less tha n or equal to 7), was derived. This sequence reflects the curve-twist- curve DNA topology which is a feature common to all Tn916 integration sites. A search of the ii. influenzae Rd genome using the new consensu s sequence identified 167 potential target sites, representing approxi mately 1% of the total genome. Only 80 of these sites were located wit hin ORFs. The presence of such a limited number of target sites places severe constraints on the use of Tn916 as a tool for generalized muta genesis of the genome of H. influenzae.