Multiple promoter inversions generate surface antigenic variation in Mycoplasma penetrans
Multiple promoter inversions generate surface antigenic variation in Mycoplasma penetrans
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DOI：
10.1128/jb.185.1.231-242.2003
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发表时间：
2003-01-01
影响因子：
3.2
通讯作者：
Kenri, T
中科院分区：
文献类型：
--
作者：
Horino, A;Sasaki, Y;Kenri, T
穿透支原体是支原体属中新发现的一种。它首先是从人类免疫缺陷病毒（HIV）感染患者的尿液样本中分离出来的。 M. penetrans 频繁地改变其表面抗原谱。这些变化源自表面膜脂蛋白 P35 家族的 ONOFF 相变化。 P35家族脂蛋白是在穿壁支原体感染期间被人类免疫系统识别的主要抗原，并且由mpl基因编码。 P35家族脂蛋白的相变发生在mpl基因的转录水平；然而，确切的遗传机制尚不清楚。在本研究中，研究了穿M. penetrans表面抗原谱变化的分子机制。重点是 46-kDa 蛋白质，该蛋白质存在于穿透分枝杆菌菌株 HF-2 中，但不存在于典型菌株 GTU 中。 46-kDa 蛋白是先前报道的 mpl 基因 pepIMP13 的产物，其氨基末端序列与 P35 家族脂蛋白的氨基末端序列相同。对pepIMP13基因区域的核苷酸测序分析表明，该基因含有启动子的135 bp DNA具有可逆元件的结构，充当基因表达的开关。此外，利用最近可用的该细菌的全基因组序列数据，鉴定了穿通穿甲杆菌 HF-2 的所有 mpl 基因。 M. penetrans HF-2 基因组中至少有 38 个 mpl 基因。有趣的是，这些 mpl 基因中的大多数都具有可逆的启动子样序列，类似于 pepIMP13 基因启动子的序列。提出了通过多个启动子倒位产生表面抗原变异的模型。
Mycoplasma penetrans is a newly identified species of the genus Mycoplasma. It was first isolated from a urine sample from a human immunodeficiency virus (HIV)-infected patient. M. penetrans changes its surface antigen profile with high frequency. The changes originate from ONOFF phase variations of the P35 family of surface membrane lipoproteins. The P35 family lipoproteins are major antigens recognized by the human immune system during M. penetrans infection and are encoded by the mpl genes. Phase variations of P35 family lipoproteins occur at the transcriptional level of mpl genes; however, the precise genetic mechanisms are unknown. In this study, the molecular mechanisms of surface antigen profile change in M. penetrans were investigated. The focus was on the 46-kDa protein that is present in M. penetrans strain HF-2 but not in the type strain, GTU. The 46-kDa protein was the product of a previously reported mpl gene, pepIMP13, with an amino-terminal sequence identical to that of the P35 family lipoproteins. Nucleotide sequencing analysis of the pepIMP13 gene region revealed that the promoter-containing 135-bp DNA of this gene had the structure of an invertible element that functioned as a switch for gene expression. In addition, all of the mpl genes of M. penetrans HF-2 were identified using the whole-genome sequence data that has recently become available for this bacterium. There are at least 38 mpl genes in the M. penetrans HF-2 genome. Interestingly, most of these mpl genes possess invertible promoter-like sequences, similar to those of the pepIMP13 gene promoter. A model for the generation of surface antigenic variation by multiple promoter inversions is proposed.