SpvR binds to regulatory sequences upstream of both the spvR and spvA promoters , inducing its own expression of the spvABCD operon .
SpvR positively regulates the plasmid-encoded spvABCD operon
Furthermore , RpoS appears essential for SpvR-assisted induction of the spvABCD genes .
SpvR induces the expression of the spvABCD operon .