Genomic Identification of SinR Transcription Factor Binding Sites in Nitrogen Fixing Bacterium Bradyrhizobium japonicum

Abstract

SinR is a transcription factor which controls expression of stress tolerance sin genes related to alternate development processes under stress condition. Identification of genome wide SinR-box motif and their regulated genes has not been worked out yet in Bradyrhizobium japonicum. For this, a weight matrix of 9 bp was developed from the known promoter sequences of Bacillus subtilis, which was then used for genome wide identification of co-regulated genes. The methodology first involves phylogenetic footprinting of SinR regulated genes and then construction of scoring matrix through ‘Consensus’ and confirmation through MEME & D-Matrix tools. Genomic prediction was done through ‘Patser’ program and confirmation through ‘PossumSearch’ program in Linux system. Results showed that all the 371 predicted genes belongs to 9 different functional classes, in which 221 found in operons with more than 80% Sin-box motif similarity. Similar approach can be used in other bacteria to explore hidden genomic regulatory network.