Genetic determinants of swimming motility in the squid light-organ symbiont Vibrio fischeri
Genetic determinants of swimming motility in the squid light-organ symbiont Vibrio fischeri
复制标题
DOI：
10.1002/mbo3.96
复制
发表时间：
2013-08-01
期刊：
影响因子：
3.4
通讯作者：
Ruby, Edward G.
中科院分区：
文献类型：
--
作者：
Brennan, Caitlin A.;Mandel, Mark J.;Ruby, Edward G.
细菌鞭毛的运动是一种复杂的细胞行为，夏威夷短尾乌贼的发光器官需要由有益的生物发光共生菌费氏弧菌定植。我们通过以下方式对这一行为的基础进行了表征：(I)进行正向遗传筛选，以确定软琼脂运动能力缺陷的突变体；以及(Ii)转录分析，以确定鞭毛主调控子fla下游表达的基因。发现了软琼脂运动性严重缺陷的突变体，这是因为插入了与鞭毛运动性有关的基因和意想不到的基因，包括那些预测编码假想蛋白质和细胞分裂相关蛋白质的基因。对突变体进入产生性共生的能力的分析表明，鞭毛运动性突变体是缺乏的，而趋化性突变体能够将幼体鱿鱼的一部分定植到发光水平。在没有Flra的情况下，软琼脂中正常运动所需的33个基因也下调了，这表明它们属于费氏弧菌的鞭毛调节子。对鞭毛运动基因motA1、motB1、fliL1和fliL2可能的平行对偶基因的突变表明，motA1、motB1和fliL1和fliL2都可能对软琼脂的运动起作用，而motA2和motB2则不起作用。利用这些互补的方法，我们鉴定了鱼鞭毛运动性的遗传基础，并进一步了解了鞭毛运动性和趋化性在幼乌贼定植中的作用，包括鉴定了11个新的突变体，这些突变体不能进入生产性的光-器官共生。
Bacterial flagellar motility is a complex cellular behavior required for the colonization of the light-emitting organ of the Hawaiian bobtail squid, Euprymna scolopes, by the beneficial bioluminescent symbiont Vibrio fischeri. We characterized the basis of this behavior by performing (i) a forward genetic screen to identify mutants defective in soft-agar motility, as well as (ii) a transcriptional analysis to determine the genes that are expressed downstream of the flagellar master regulator FlrA. Mutants with severe defects in soft-agar motility were identified due to insertions in genes with putative roles in flagellar motility and in genes that were unexpected, including those predicted to encode hypothetical proteins and cell division-related proteins. Analysis of mutants for their ability to enter into a productive symbiosis indicated that flagellar motility mutants are deficient, while chemotaxis mutants are able to colonize a subset of juvenile squid to light-producing levels. Thirty-three genes required for normal motility in soft agar were also downregulated in the absence of FlrA, suggesting they belong to the flagellar regulon of V. fischeri. Mutagenesis of putative paralogs of the flagellar motility genes motA, motB, and fliL revealed that motA1, motB1, and both fliL1 and fliL2, but not motA2 and motB2, likely contribute to soft-agar motility. Using these complementary approaches, we have characterized the genetic basis of flagellar motility in V. fischeri and furthered our understanding of the roles of flagellar motility and chemotaxis in colonization of the juvenile squid, including identifying 11 novel mutants unable to enter into a productive light-organ symbiosis.