"Optimal Toxin Gene Expression"

"Our data strongly suggest that an additional factor(s) is involved in regulation of pag and that the relative amounts of such a factor(s) and AtxA are important for optimal toxin gene expression."

Regulation of anthrax toxin activator gene (atxA) expression in Bacillus anthracis: temperature, not CO2/bicarbonate, affects AtxA synthesis.
http://iai.asm.org/content/65/7/2576.abstract