HORIZONTAL TRANSFER OF A PHOSPHATASE GENE AS EVIDENCE FOR MOSAIC STRUCTURE OF THE SALMONELLA GENOME
HORIZONTAL TRANSFER OF A PHOSPHATASE GENE AS EVIDENCE FOR MOSAIC STRUCTURE OF THE SALMONELLA GENOME
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DOI：
10.1002/j.1460-2075.1992.tb05175.x
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发表时间：
1992-04-01
期刊：
影响因子：
11.4
通讯作者：
OCHMAN, H
中科院分区：
文献类型：
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作者：
GROISMAN, EA;SAIER, MH;OCHMAN, H
大肠杆菌和鼠伤寒沙门氏菌的基因组在碱基组成、染色体大小以及基因的顺序、方向和间距方面相似，但在29个“环”（一个物种特有的区域）方面有所不同。为了评估肠道细菌基因组结构和组织的遗传基础，我们检测了编码非特异性酸性磷酸酶（phoN）的基因，该基因在96分钟时映射到鼠伤寒沙门氏菌染色体上的一个环。我们检测到非典型碱基组成、密码子使用模式和三核苷酸频率。含有phoN的1.4 kb区域的总体碱基组成为43% G + C，而phoN阅读框密码子第三位的G + C含量仅为39%，远低于沙门氏菌染色体的平均52%。测定了14种革兰氏阴性菌的非特异性酸性磷酸酶活性，结果表明，仅在基因组G + C含量较低的摩根氏摩根菌和斯华普罗维登菌中检测到非特异性酸性磷酸酶活性。沙门氏菌中phoN基因的上游序列与incFII质粒的轨道区域高度相似，这表明phoN基因以及整个环结构可能是在质粒介导的事件中通过横向传播获得的。
The genomes of Escherichia coli and Salmonella typhimurium are similar with respect to base composition, chromosome size, and the order, orientation and spacing of genes, but differ with respect to some 29 'loops', regions unique to one species. To evaluate the genetic basis for the structure and organization of the enteric bacterial genomes, we examined the gene encoding a nonspecific acid phosphatase (phoN) which maps to a loop at 96 min on the S.typhimurium chromosome. We detected atypical base composition, codon usage pattern and trinucleotide frequencies. The 1.4 kb region containing phoN had an overall base composition of 43% G + C, while the G + C content at the third positions of codons in the phoN reading frame is only 39%, much lower than the Salmonella chromosome which averages 52%. Non-specific acid phosphatase activity, assayed in 14 Gram-negative species, was detected only in Morganella morganii and Providencia stuartii, organisms with low genomic G + C contents. Upstream of the phoN gene in Salmonella is a sequence with high similarity to the obit region of incFII plasmid, suggesting that the phoN gene, and perhaps the entire loop structure, was acquired by lateral transmission in a plasmid-mediated event.