FIG. 8.

Model for the roles of syp regulators in biofilm formation in V. fischeri. Transcription of the syp locus can be induced by overexpression of RscS or SypF (SypF1), acting through SypG. The Syp structural proteins contribute to the production of a Syp polysaccharide, involved in cell-cell aggregation phenotypes, such as wrinkled colonies and pellicles. SypE contributes by an unknown mechanism to these phenotypes; it also appears to inhibit SypG activity (not depicted). SypF overexpression may activate VpsR, ultimately promoting cellulose operon (VFA0881-885) expression or cellulose synthesis. The result of these interactions is enhanced cell-surface interactions. Block arrows indicate genes (depicted in gray for sypE and sypG and in white for sypF), and line arrows indicate activation. The question mark indicates that the level at which VpsR exerts its effect is not yet known.