Inversions over the terminus region in Salmonella and Escherichia coli:: IS200s as the sites of homologous recombination inverting the chromosome of Salmonella enterica serovar Typhi
Inversions over the terminus region in Salmonella and Escherichia coli:: IS200s as the sites of homologous recombination inverting the chromosome of Salmonella enterica serovar Typhi
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DOI：
10.1128/jb.184.22.6190-6197.2002
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发表时间：
2002-11-01
影响因子：
3.2
通讯作者：
Sanderson, KE
中科院分区：
文献类型：
--
作者：
Alokam, S;Liu, SL;Sanderson, KE
在培养物中，肠道细菌如沙门氏菌血清型鼠伤寒LT 2和大肠杆菌K12中的基因组重排（复制和倒位）很常见（10（-3）至10（-5）），但在野生型菌株中，这些基因组重排很少存活。然而，倒位通常存在于复制末端（TER）区域，在那里双向DNA复制终止;肠道血清型鼠伤寒沙门氏菌（S.伤寒肠杆菌CT 18、伤寒肠杆菌E. coli K12和E. coliO 157：H7中发现了跨越TER区域的基因组倒位。假设S.在伤寒CT 18血清型中发现了556 kb的倒位，在大肠杆菌中发现了约700 kb的倒位。coli K12和E. coli O157：H7。此外，在E. coli O 157：H7与E. coli K12。PCR分析证实所有S.所测试的伤寒沙门氏菌血清型菌株，而不是其它沙门氏菌血清型菌株，在IS 200插入的确切位点处具有倒位。我们的结论是，TER区域的倒位存活下来，因为它们不会显着改变复制平衡，或者因为它们是补偿机制的一部分，以恢复染色体平衡后，它被插入，删除或其他倒位破坏。
Genomic rearrangements (duplications and inversions) in enteric bacteria such as Salmonella enterica serovar Typhimurium LT2 and Escherichia coli K12 are frequent (10(-3) to 10(-5)) in culture, but in wild-type strains these genomic rearrangements seldom survive. However, inversions commonly survive in the terminus of replication (TER) region, where bidirectional DNA replication terminates; nucleotide sequences from S. enterica serovar Typhimurium LT2, S. enterica serovar Typhi CT18, E. coli K12, and E. coli O157:H7 revealed genomic inversions spanning the TER region. Assuming that S. enterica serovar Typhimurium LT2 represents the ancestral genome structure, we found an inversion of 556 kb in serovar Typhi CT18 between two of the 25 IS200 elements and an inversion of about 700 kb in E. coli K12 and E. coli O157:H7. In addition, there is another inversion of 500 kb in E. coli O157:H7 compared with E. coli K12. PCR analysis confirmed that all S. enterica serovar Typhi strains tested, but not strains of other Salmonella serovars, have an inversion at the exact site of the IS200 insertions. We conclude that inversions of the TER region survive because they do not significantly change replication balance or because they are part of the compensating mechanisms to regain chromosome balance after it is disrupted by insertions, deletions, or other inversions.