Latifi A, Winson M K, Foglino M, Bycroft B W, Stewart G S, Lazdunski A, Williams P
Laboratoire d'Ingenierie et Dynamique des Systémes Membranaires, Centre National de la Recherche Scientifique, Marseille, France.
Mol Microbiol. 1995 Jul;17(2):333-43. doi: 10.1111/j.1365-2958.1995.mmi_17020333.x.
In Pseudomonas aeruginosa PAO1, expression of elastase is dependent upon an interaction between the positive transcriptional activator LasR and the auto-inducer molecule N-(3-oxododecanoyl)-L-homoserine lactone (OdDHL), the synthesis of which is directed by LasI. Previously we have shown that in PAN067, an elastase-negative mutant of PAO1, elastase production can be restored to some extent by addition of exogenous N-(3-oxohexanoyl)-L-homoserine lactone (OHHL). Here we report that PAN067 is also defective in the production of alkaline protease, haemolysin, cyanide, pyocyanin and autoinducer(s). As neither addition of exogenous OdDHL nor introduction of lasR restored PAN067 to the parental phenotype, we sought to complement PAN067 with PAO1 DNA. From a cosmid library, a 2 kb DNA fragment was identified which re-established production of autoinducer(s) and exoproducts in PAN067. From the nucleotide sequence of this fragment, two genes termed rhIR and rhII were identified. RhII is responsible for autoinducer synthesis and shares 31% homology with LasI; RhIR has been previously identified in P. aeruginosa strain DSM2659 as a regulator of rhamnolipid biosynthesis and shares 28% identity with LasR. These data provide clear evidence that multiple families of quorum-sensing modulons interactively regulate gene expression in P. aeruginosa.
在铜绿假单胞菌PAO1中，弹性蛋白酶的表达取决于正向转录激活因子LasR与自诱导分子N-(3-氧代十二烷酰基)-L-高丝氨酸内酯(OdDHL)之间的相互作用，OdDHL的合成由LasI指导。此前我们已经表明，在PAO1的弹性蛋白酶阴性突变体PAN067中，添加外源性N-(3-氧代己酰基)-L-高丝氨酸内酯(OHHL)可在一定程度上恢复弹性蛋白酶的产生。在此我们报告，PAN067在碱性蛋白酶、溶血素、氰化物、绿脓菌素和自诱导物的产生方面也存在缺陷。由于添加外源性OdDHL或引入lasR均未使PAN067恢复到亲本表型，我们试图用PAO1 DNA对PAN067进行互补。从一个黏粒文库中，鉴定出一个2 kb的DNA片段，该片段可在PAN067中重新建立自诱导物和胞外产物的产生。从该片段的核苷酸序列中，鉴定出两个基因，分别称为rhIR和rhII。RhII负责自诱导物的合成，与LasI具有31%的同源性；RhIR先前在铜绿假单胞菌DSM2659菌株中被鉴定为鼠李糖脂生物合成的调节因子，与LasR具有28%的同一性。这些数据提供了明确的证据，表明多个群体感应调节子家族在铜绿假单胞菌中相互作用地调节基因表达。
