Gottesman S, Trisler P, Torres-Cabassa A
J Bacteriol. 1985 Jun;162(3):1111-9. doi: 10.1128/jb.162.3.1111-1119.1985.
The synthesis of the Escherichia coli capsular polysaccharide varies with growth medium, temperature of growth, and genetic background. lac fusions to genes necessary for capsule synthesis (cps) demonstrated that these genes are regulated negatively in vivo by the lon gene product. We have now isolated, characterized, and mapped mutations in three new regulatory genes (rcs, for regulator of capsule synthesis) that control expression of these same fusions. rcsA and rcsB are positive regulators of capsule synthesis. rcsA is located at min 43 on the E. coli map, whereas rcsB lies at 47 min. rcsC, a negative regulator of capsule synthesis, is located at min 47, close to rcsB. All three regulatory mutations are unlinked to either the structural genes cpsA-F or lon. Mutations in all three rcs genes are recessive to the wild type. We postulate that lon may regulate capsule synthesis indirectly, by regulating the availability of one of the positive regulators.
大肠杆菌荚膜多糖的合成会因生长培养基、生长温度和遗传背景的不同而有所变化。与荚膜合成（cps）所需基因的lac融合表明，这些基因在体内受到lon基因产物的负调控。我们现已分离、鉴定并定位了三个新的调控基因（rcs，即荚膜合成调节因子）中的突变，这些基因控制着相同融合基因的表达。rcsA和rcsB是荚膜合成的正调控因子。rcsA位于大肠杆菌图谱的43分钟处，而rcsB位于47分钟处。rcsC是荚膜合成的负调控因子，位于47分钟处，靠近rcsB。所有这三个调控突变均与结构基因cpsA - F或lon不连锁。所有三个rcs基因的突变相对于野生型都是隐性的。我们推测，lon可能通过调节其中一个正调控因子的可用性来间接调节荚膜合成。
