Transcriptome comparison of B. anthracis Ames and isogenic sinR-null mutant, UTA21

To establish the SinR regulon in B. anthracis, gene expression of the fully virulent Ames strain and the isogenic sinR-null strains were compared using expression microarray analysis. Cultures of the two B. anthracis strains tested were grown in triplicate in LB broth to mid-exponential phase (O.D.600 = 0.5-0.6) or early stationary phase of growth (O.D.600 = 3.5-3.9). Cells were pelleted through centrifugation and frozen at -80ºC. Total RNA was isolated using a hot phenol method, converted to cDNA, fragmented, labeled, and hybridized to our Affymetrix microarray. Estimates of gene expression were calculated using GCOS software v1.4.