Genome sequence of Shigella flexneri 2a: insights into pathogenicity through comparison with genomes of Escherichia coli K12 and O157.
We have sequenced the genome of Shigella flexneri serotype 2a, the most prevalent species and serotype that causes bacillary dysentery or shigellosis in man. The whole genome is composed of a 4 607 203 bp chromosome and a 221 618 bp virulence plasmid, designated pCP301. While the plasmid shows minor divergence from that sequenced in serotype 5a, striking characteristics of the chromosome have been revealed. The S.flexneri chromosome has, astonishingly, 314 IS elements, more than 7-fold over those possessed by its close relatives, the non-pathogenic K12 strain and enterohemorrhagic O157:H7 strain of Escherichia coli. There are 13 translocations and inversions compared with the E.coli sequences, all involve a segment larger than 5 kb, and most are associated with deletions or acquired DNA sequences, of which several are likely to be bacteriophage-transmitted pathogenicity islands. Furthermore, S.flexneri, resembling another human-restricted enteric pathogen, Salmonella typhi, also has hundreds of pseudogenes compared with the E.coli strains. All of these could be subjected to investigations towards novel preventative and treatment strategies against shigellosis.
Jin
Qi
Q
State Key Laboratory for Molecular Virology and Genetic Engineering, Beijing 100052, China. zdsys@sina.com
Yuan
Zhenghong
Z
Xu
Jianguo
J
Wang
Yu
Y
Shen
Yan
Y
Lu
Weichuan
W
Wang
Jinhua
J
Liu
Hong
H
Yang
Jian
J
Yang
Fan
F
Zhang
Xiaobing
X
Zhang
Jiyu
J
Yang
Guowei
G
Wu
Hongtao
H
Qu
Di
D
Dong
Jie
J
Sun
Lilian
L
Xue
Ying
Y
Zhao
Ailan
A
Gao
Yishan
Y
Zhu
Junping
J
Kan
Biao
B
Ding
Keyue
K
Chen
Shuxia
S
Cheng
Hongsong
H
Yao
Zhijian
Z
He
Bingkun
B
Chen
Runsheng
R
Ma
Dalong
D
Qiang
Boqin
B
Wen
Yumei
Y
Hou
Yunde
Y
Yu
Jun
J
D000595:Amino Acid Sequence; D001483:Base Sequence; D007446:Chromosome Inversion; D004251:DNA Transposable Elements; D004926:Escherichia coli / Q000235:genetics; D019453:Escherichia coli O157 / Q000235:genetics; D016680:Genome, Bacterial; D008969:Molecular Sequence Data; D010957:Plasmids; D011544:Pseudogenes; D016415:Sequence Alignment; D012763:Shigella flexneri / Q000235:genetics* / Q000472:pathogenicity*; D014178:Translocation, Genetic
D004251:DNA Transposable Elements