Complete circuit diagram of key regulatory genes in sporulation.

<p>Spo0A is a key protein that directs the transcriptional regulation of downstream gene, including asymmetric division and the expression of SigF and SigE, which are special transcription factors of pre-spore and mother cell, respectively. The two transcription factors decide the regulation of the development of spore. Red line, inhibition; Orange line, activation; Green, translation.