Meier J T, Simon M I, Barbour A G
Cell. 1985 Jun;41(2):403-9. doi: 10.1016/s0092-8674(85)80013-1.
Borrelia hermsii, an agent of relapsing fever, undergoes antigenic variation in its host. Surface-exposed proteins with differing primary structures determine the serotype of each organism. Using amino acid sequence data from two of these variable proteins, we synthesized two mixed-sequence oligonucleotides and then used the oligonucleotides to probe mRNA and DNA of three isogenic serotypes of B. hermsii. In Northern blots the probes were specific for the mRNA of the homologous serotype. Southern blots revealed two classes of hybridizing fragments: those common to the three serotypes and those specific for a particular serotype. A serotype-specific DNA fragment, which had hybridized to both oligonucleotide probes, was cloned. Subsequent use of the cloned fragment as a probe provided further evidence that antigenic variation in B. hermsii is associated with DNA rearrangements and with occurrence of expression-linked copies of all, or part, of an antigen-specifying gene.
赫氏疏螺旋体是回归热的病原体，在宿主体内会发生抗原变异。具有不同一级结构的表面暴露蛋白决定了每个生物体的血清型。利用其中两种可变蛋白的氨基酸序列数据，我们合成了两条混合序列寡核苷酸，然后用这些寡核苷酸探测赫氏疏螺旋体三种同基因血清型的mRNA和DNA。在Northern印迹中，探针特异于同源血清型的mRNA。Southern印迹显示出两类杂交片段：一类是三种血清型共有的，另一类是特定血清型特有的。一个与两条寡核苷酸探针都杂交的血清型特异性DNA片段被克隆。随后将克隆片段用作探针进一步证明，赫氏疏螺旋体的抗原变异与DNA重排以及抗原特异性基因全部或部分的表达连锁拷贝的出现有关。
