BACTERIAL ADP-RIBOSYLTRANSFERASES--A ROLE IN SYMBIOSIS

费氏弧菌-小角真核菌轻器官共生是典型的动物细菌相互作用的例证——稳定的、非致病性的细菌定植在宿主组织中，动物及其微生物群能够识别、发出信号并相互影响发育。一些轻器官组织的发育变化只发生在感染费氏弧菌的动物身上，然而，细菌定植和诱导发育的机制尚不清楚。本研究的目的是研究费氏弧菌（V. fischeri）输出的两种新型adp -核糖基转移酶（adpr） HvnA和HvnB在大肠杆菌定殖和引发发育变化中的作用。adpr共价修饰蛋白质，内源性的adpr调节重要的细胞过程，而已知的细菌分泌的adpr在致病相互作用中对宿主产生毒性作用。因此，我们假设adpr在这种共生关系中发挥作用。我们建议：(i)克隆和表征鱿鱼共生体的hvnA和hvnB操作子，（ii）确定hvnA和hvnB基因是否在鱿鱼光器官中表达，（iii）测试缺乏hvnA和/或hvnB的突变体在鱿鱼光器官中定植和触发发育的能力，（iv）在光器官中免疫定位hvnA和hvnB， (v)确定特异性宿主蛋白是否被hvnA和hvnB进行adp核糖化。

DESCRIPTION The Vibrio fischeri-Euprymna scolopes light organ symbiosis exemplifies typical animal bacterial interactions-stable, non-pathogenic bacterial colonization of host tissue with both the animal and its microflora able to recognize, signal, and developmentally influence one another. Several developmental changes in light organ tissue occur only in animals infected with V. fischeri, however the mechanisms underpinning bacterial colonization and induction of development are unknown. The aim of this proposal is to investigate the role of two noel ADP-ribosyltransferases (ADPrs) exported by V. fischeri, HvnA and HvnB, in this bacterium's ability to colonize and trigger developmental changes in E. scolopes. ADPRs covalently modify proteins, and endogenous ones regulate important cellular processes while known excreted bacterial ADPrs exert toxic effects on hosts in pathogenic interactions. We therefore hypothesize that ADPrs play a role in this symbiosis We propose to: (i) clone and characterize the hvnA and hvnB operons from a squid symbion, (ii) determine whether hvnA and hvnB genes are expressed in the E. scolopes light organ, (iii) test the ability of mutants lacking hvnA and/or hvnB to colonize and trigger development in E. scolopes, (iv) localize HvnA and HvnB within the light organ immunologically and (v) determine whether specific host proteins are ADP-ribosylated by HvnA and HvnB.