Back to article: Milestones in Bacillus subtilis sporulation research
FIGURE 5: Cascade of sporulation-specific σ factors in B. subtilis. Immediately after polar septation, σF is activated in the forespore. σF activation triggers an intercompartmental signaling cascade that leads to the activation of σE in the mother cell. Together σF and σE control gene expression during engulfment. Roughly coincident with the completion of engulfment, σF is replaced by σG in the forespore, which leads to the subsequent activation of σK in the mother cell. σG and σK control gene expression in the forespore and the mother cell, respectively, after engulfment.