Gene rearrangements in the vsa locus of Mycoplasma pulmonis
Gene rearrangements in the vsa locus of Mycoplasma pulmonis
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DOI：
10.1128/jb.182.10.2900-2908.2000
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发表时间：
2000-05-01
影响因子：
3.2
通讯作者：
Dybvig, K
中科院分区：
文献类型：
--
作者：
Shen, XJ;Gumulak, J;Dybvig, K
肺支原体的vsa基因编码V-1脂蛋白。大多数V-1蛋白含有重复结构域，被认为参与支原体-宿主细胞相互作用。在此之前，我们已经报道了6个vsa基因的分离和鉴定，这些基因包含M. pulmonis菌株RD 735 -15。在当前的研究中，使用vsa特异性探针从KD 735 -15 DNA的基因组文库中克隆了几个片段，并组装了包含11个vsa基因的单个20 kb重叠群。vsa基因座的中间区域包含一个大的开放阅读框（ORF），该读框不是vsa基因，并且在某些菌株中经历了内部缺失。预测ORF编码可能在疾病发病机制中起作用的膜蛋白。目的检测一株M.对与KD 735 -15无关的肺杆菌CT株进行了研究。通过Southern杂交和基因组克隆分析，发现CT具有KD 735 -15 vsaA、-C、-E和-F基因的同源物以及在KD 735 -15中未发现的两个独特基因（vsaG和vsaH）。高频率，位点特异性DNA倒位用于调节单个V-1蛋白的相位可变生产。作为结果的vsa重组产物的序列分析，提出了一个模型，其中DNA倒位产生的链交换涉及至少6个核苷酸的vrs框。
The vsa genes of Mycoplasma pulmonis encode the V-1 lipoproteins. Most V-1 proteins contain repetitive domains and are thought to be involved in mycoplasma-host cell interactions. Previously, we have reported the isolation and characterization of six vsa genes comprising a 10-kb region of the genome of M. pulmonis strain RD735-15. In the current study, vsa-specific probes were used to clone several fragments from a genomic library of KD735-15 DNA and assemble a single 20-kb contig containing 11 vsa genes. The middle region of the vsa locus contains a large open reading frame (ORF) that is not a vsa gene and has undergone an internal deletion in some strains. The ORF is predicted to encode a membrane protein that may have a role in disease pathogenesis. To examine vsa genes in a strain of M. pulmonis that is unrelated to KD735-15, strain CT was studied. Through Southern hybridization and genomic cloning analyses, CT was found to possess homologs of the KD735-15 vsaA, -C, -E, and -F genes and two unique genes (vsaG and vsaH) that were not found in KD735-15. High-frequency, site-specific DNA inversions serve to regulate the phase-variable production of individual V-1 proteins. As a result of the sequence analysis of vsa recombination products, a model in which DNA inversion arises from strand exchange involving at least six nucleotides of the vrs box is proposed.