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Phage sequences in bacterial genomes
Spreading the tools of death
The Bacteriophage 933W
Certain bacterial viruses (called bacteriophages) carry with them extra genes that play no role in viral function. In some cases, the extra DNA encodes virulence factors, proteins that can make the difference between harmless and pathogenic bacteria. You are studying the bacteriophage 933W, which is known to insert itself into bacterial genomes as a prophage. 933W carries the gene for a potent toxin, Shiga toxin 2, which is responsible for the virulence of enterohemorrhagic E. coli (EHEC) strain EDL933 (the "Jack-in-the-Box strain" that caused an outbreak in the Pacific Northwest in 1993).
If the critical determinant of pathogenesis is carried by a bacteriophage, then the spread of phage can create new and potent pathogens.
What determines the bacterial targets phage 933W can infect?
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