Carson S D, Stone B, Beucher M, Fu J, Sparling P F
Departments of Microbiology and Immunology and Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
Mol Microbiol. 2000 May;36(3):585-93. doi: 10.1046/j.1365-2958.2000.01873.x.
FetA, the recently characterized gonococcal ferric enterobactin receptor, exhibited extremely rapid phase variation between high- and low-expression levels. The frequency of phase variation was approximately 1.3% in both directions in gonococcal strain FA1090. FetA expression in the 'high phase' was significantly greater than the level of expression in the 'low phase'. Expression levels correlated with the number of cytosine residues in a string of cytosines located close to the transcriptional start site for fetA between the putative -10 and -35 consensus sequences. Antibody production against FetA commonly occurs in infected patients, and we therefore hypothesize that phase variation reflects a balance between the advantages of being able to use a ferric siderophore as an iron source and evasion of the host immune response.
FetA是最近鉴定出的淋病奈瑟菌铁肠菌素受体，其在高表达水平和低表达水平之间呈现出极快的相变。在淋病奈瑟菌菌株FA1090中，两个方向的相变频率约为1.3%。“高表达阶段”的FetA表达明显高于“低表达阶段”的表达水平。表达水平与位于fetA转录起始位点附近、假定的-10和-35共有序列之间的一串胞嘧啶中的胞嘧啶残基数量相关。感染患者中通常会产生针对FetA的抗体，因此我们推测相变反映了能够利用铁载体作为铁源的优势与逃避宿主免疫反应之间的平衡。
