Sequence analysis of Stx2-converting phage VT2-Sa shows a great divergence in early regulation and replication regions.
In enterohemorrhagic Escherichia coli, Shiga toxin is produced by lysogenic prophages. We have isolated the prophage VT2-Sa that is responsible for production of Shiga toxin type 2 protein, and determined the complete nucleotide sequence of this phage DNA. The entire DNA sequence consisted of 60,942 bp, exhibiting marked similarity to the 933W phage genome. However, several differences were observed in the immunity and replication regions, where cI, cII, cIII, N, cro, O, and P genes were present: Predicted amino acid sequences of N, cI, cro, O and P in the VT2-Sa genome did not show significant similarity to the counterparts of the 933W genome; however its cI showed higher similarity to lambda. Furthermore, O and P closely resembled those of phage HK022. These observations suggest that the various degrees of homology observed in the immunity and replication regions of VT2-Sa could have resulted from frequent recombination events among the lambdoid phages, and that these regions play a key role as a functional unit for phage propagation in competition with other lambdoid phages.
Miyamoto
H
H
Faculty of Biology-Oriented Science and Technology, Department of Molecular Genetics, Kinki University, Uchita, Wakayama, Japan. miyamoto@gene.waka.kindai.ac.jp
Nakai
W
W
Yajima
N
N
Fujibayashi
A
A
Higuchi
T
T
Sato
K
K
Matsushiro
A
A
D000595:Amino Acid Sequence; D001427:Bacterial Toxins / Q000235:genetics*; D010582:Bacteriophage lambda / Q000235:genetics; D001483:Base Sequence; D003090:Coliphages / Q000235:genetics*; D004768:Enterotoxins / Q000235:genetics*; D019453:Escherichia coli O157 / Q000821:virology*; D005786:Gene Expression Regulation; D017781:Genes, Immediate-Early; D005814:Genes, Viral; D006801:Humans; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D022603:Shiga Toxins; D012762:Shigella dysenteriae
D001427:Bacterial Toxins; D004768:Enterotoxins; D022603:Shiga Toxins