Figure 5.

A schematic model of biofilm formation and gene expression involving YmdB, RpoS, and RNase III. Two different pathways for biofilm formation are proposed: an RNase III-dependent pathway in which other uncharacterized factor(s) inhibit RNase III activity, thereby upregulating biofilm formation, and an RNase III-independent pathway in which both YmdB and RpoS interdependently regulate the inhibition of biofilm formation. In terms of gene expression, the level of RpoS is post-transcriptionally regulated by YmdB either directly or indirectly via the inhibition of RNase III activity [18,20], while the level of YmdB is regulated transcriptionally by the RpoS protein [18].