Generation of Campylobacter fetus S‐layer protein diversity utilizes a single promoter on an invertible DNA segment
Generation of Campylobacter fetus S‐layer protein diversity utilizes a single promoter on an invertible DNA segment
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DOI：
10.1111/j.1365-2958.1996.tb02469.x
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发表时间：
1996-03
影响因子：
3.6
通讯作者：
J. Dworkin;M. Blaser
中科院分区：
文献类型：
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作者：
J. Dworkin;M. Blaser
胎儿弯曲杆菌野生型菌株含有表面层蛋白（SLP）的单分子阵列，并改变表达的主要SLP的抗原性。编码97 - 149 kDa SLP的8个基因组SLP基因盒之间的相互重组事件允许这种变异。为了探索SLP表达是否利用单个启动子，我们通过从质粒中拯救标记物使用插入诱变来创建突变细菌菌株。对所产生的突变体的实验分析清楚地表明，SLP表达仅利用单个sapA启动子，而对于变异C。胎儿使用DNA重排机制，包括含有该启动子的6.2kb DNA片段的倒位。这种DNA倒位将sapA启动子定位在两个相反方向的SLP基因盒之一的上游，导致其表达。此外，发生DNA重排的第二种机制以替换包围可逆元件的两个SLP基因盒中的至少一个。如先前报道的，原核生物、酵母和病毒中的启动子倒位涉及至多两个结构基因的交替表达，C.胎儿利用这一现象表达多个盒中的一个是新颖的。
Wild‐type strains of Campylobacter fetus contain a monomolecular array of surface layer proteins (SLPs) and vary the antigenicity of the predominant SLP expressed. Reciprocal recombination events among the eight genomic SLP gene cassettes, which encode 97‐ to 149 kDa SLPs, permit this variation. To explore whether SLP expression utilizes a single promoter, we created mutant bacterial strains using insertional mutagenesis by rescue of a marker from plasmids. Experimental analysis of the mutants created clearly indicates that SLP expression solely utilizes the single sapA promoter, and that for variation C. fetus uses a mechanism of DNA rearrangement involving inversion of a 6.2 kb segment of DNA containing this promoter. This DNA inversion positions the sapA promoter immediately upstream of one of two oppositely oriented SLP gene cassettes, leading to its expression. Additionally, a second mechanism of DNA rearrangement occurs to replace at least one of the two SLP gene cassettes bracketing the invertible element. As previously reported promoter inversions in prokaryotes, yeasts and viruses involve alternate expression of at most two structural genes, the ability of C. fetus to use this phenomenon to express one of multiple cassettes is novel.