Rhodobacter sphaeroides has two sets of flagellar genes, fla1 and fla2, that are responsible for the synthesis of two different flagellar structures. The expression of the fla2 genes is under control of CtrA. In several α-proteobacteria CtrA is also required for the expression of the flagellar genes, but the architecture of CtrA-dependent promoters has only been studied in detail in Caulobacter crescentus. In many cases the expression of fla genes originates from divergent promoters located a few base pairs apart, suggesting a particular arrangement of the cis-acting sites.
Última actualización: 16/11/2018