Few transcription factor binding motifs have been identified in Mtb. Transcription factors for which binding motifs have been identified include KstR [36] , DosR [67] , IdeR [68] , ZurB [69] , Crp [70] , CsoR [71] , FurA [72] , MprAB [73] , and Acr [74] . Because of the limited knowledge of transcriptional regulation in Mtb, we searched for additional motifs computationally. We combined comparative sequence analysis with microarray data to identify a large number of motifs conserved in Mycobacteria.