Objective   To identify the sequences of the SOS boxes in genome of Pseudomonas aeruginosa PAO1.    Methods   Sixteen DNA fragments containing potential SOS box in genome of PAO1 were amplified with PCR

and then fragments were primary identified through electrophoretic mobility shift assay (EMSA) with purified LexA expressing protein. The SOS boxes sequence in the 2 positive fragments were identified by DNase Ⅰ foot printing testing

and the palindrome sequence in the 2 SOS boxes was analyzed. Based on the palindrome sequence

the putative SOS boxes and theirs regulated genes were primary searched in Pseudomonas aeruginosa PAO1.    Results   Two SOS boxes sequence in the genome of PAO1 were identified by DNase Ⅰfoot printing test

they are“CTGTCTACTTATACAG” sequence in the location of 4 052 647 to 4 052 662 bp and “CTGTCTACTTATACAG” sequence in the location of 5 349 888 to 5 349 903 bp in the genome of PAO1. And the palindrome sequence of the SOS boxes is “CTG…CAG”. Based on this sequence

10 putative SOS boxes and their regulated genes were searched.    Conclusion   Two SOS boxes sequences in genome of PAO1 are primary identified

and 10 putative SOS boxes are selected in this study.