Polyamine modulon. [More information is available at EcoGene: EG10291]. FecI (sigma19) was first described as a protein that regulated the expression of genes involved in the transport of ferric citrate ; later, it was determined as sigma factor based on similarities to a subgroup of sigma70 factors, and it binds to the fec transport gene promoter upstream fecA . [More information is available at EcoCyc: EG10291].