Swanson J, Morrison S, Barrera O, Hill S
Laboratory of Microbial Structure and Function, National Institute of Allergy and Infectious Disease, Rocky Mountain Laboratories, Hamilton, Montana 59840.
J Exp Med. 1990 Jun 1;171(6):2131-9. doi: 10.1084/jem.171.6.2131.
Recombination-dependent alterations of their expressed pilin gene (pilE) enable gonococci to synthesize a myriad of structurally/antigenically different pili and to reversibly switch their pilus production on and off. These changes have been ascribed both to DNA transformation and to intragenomic recombination between pilE and silent pilin genes (pilS). We examined the pilus changes in gonococci that are incompetent for transformation because of their DNA uptake deficiency (dud) mutation, pilus- (P-) phenotype, or both. Though incompetent for DNA transformation, dud cells displayed pilus antigenic variation and underwent reversible pilus variations much like their wild-type parent. Wild-type P- with a pilE nonsense mutation were also virtually nontransformable, but they reverted to P+ at high frequencies. The pilin mRNA sequence changes that accompanied pilus transitions in these nontransformable dud and P- gonococci represent insertion of pilS stretches into their respective pilE, apparently via intragenomic recombination.
其表达的菌毛蛋白基因（pilE）依赖重组的改变使淋球菌能够合成大量结构/抗原性不同的菌毛，并能可逆地开启和关闭菌毛产生。这些变化既归因于DNA转化，也归因于pilE与沉默菌毛蛋白基因（pilS）之间的基因组内重组。我们研究了由于DNA摄取缺陷（dud）突变、菌毛（P-）表型或两者兼而有之而无法进行转化的淋球菌中的菌毛变化。尽管dud细胞无法进行DNA转化，但它们表现出菌毛抗原变异，并经历了与野生型亲本非常相似的可逆菌毛变异。具有pilE无义突变的野生型P-实际上也无法转化，但它们以高频率回复为P+。在这些无法转化的dud和P-淋球菌中，伴随菌毛转变的菌毛蛋白mRNA序列变化代表pilS片段显然通过基因组内重组插入到它们各自的pilE中。
