The complete sequence and analysis of the large virulence plasmid pSS of Shigella sonnei.
The complete sequence of pSS, which is the large virulence plasmid of Shigella sonnei, was determined. The 214-kb plasmid is composed of segments of virulence-associated genes, the O-antigen gene clusters, a range of replication and maintenance genes, and large numbers of insertion sequence (IS) elements. Two hundred and forty-one open reading frames (ORFs) were identified, of which 117 are highly homologous to IS elements or transposases, 57 are homologous to known pathogenesis-associated proteins, and 30 are related to replication, plasmid maintenance, or other metabolic functions. Thirty-seven ORFs have no similarity to proteins with a known function, including two with no significant similarity to any hypothetical proteins. Interestingly, 10 ORFs encoding O-antigen gene clusters were identified on the plasmid and this is markedly different from most other Shigella spp. virulent plasmids. A novel toxin-antitoxin system, a series of stbDE homologs, was found on the plasmid immediately downstream of the replication region; the sole segregation stability system may be responsible for the instability of pSS. The pSS plasmid is a mixture of genes with different origins and functions. The sequence suggests a remarkable history of IS-mediated recombination and acquisition of DNA across a range of bacterial species.
Jiang
Yan
Y
State Key Laboratory for Molecular Virology and Genetic Engineering, 6 Rongjing Eastern Street, BDA Beijing 100176, China.
Yang
Fan
F
Zhang
Xiaobing
X
Yang
Jian
J
Chen
Lihong
L
Yan
Yongliang
Y
Nie
Huan
H
Xiong
Zhaohui
Z
Wang
Jing
J
Dong
Jie
J
Xue
Ying
Y
Xu
Xingye
X
Zhu
Yafang
Y
Chen
Shuxia
S
Jin
Qi
Q
D001426:Bacterial Proteins / Q000235:genetics; D001482:Base Composition; D019915:DNA Primase; D004261:DNA Replication / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D004706:Endodeoxyribonucleases / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics; D005090:Exodeoxyribonucleases / Q000235:genetics; D022761:Gene Transfer, Horizontal; D008969:Molecular Sequence Data; D005810:Multigene Family; D019081:O Antigens / Q000235:genetics; D016366:Open Reading Frames; D010957:Plasmids / Q000235:genetics*; D017421:Sequence Analysis; D012764:Shigella sonnei / Q000235:genetics / Q000472:pathogenicity*; D014774:Virulence / Q000235:genetics
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D019081:O Antigens; C052883:chromosome partition proteins, bacterial; D019915:DNA Primase; D012321:DNA-Directed RNA Polymerases; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases; C121791:dnaG protein, E coli