title: Multiple procaryotic ribonucleic acid polymerase sigma factors.
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics*; D005075:Biological Evolution; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics*; D009876:Operon; D011401:Promoter Regions, Genetic; D012808:Sigma Factor / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D012808:Sigma Factor; D014157:Transcription Factors; D012321:DNA-Directed RNA Polymerases