All three phage genomes included a homologue of the tum gene of coliphage 186 , which encodes a LexA-repressed cI antirepressor .
Control region of Fels-2 tum gene includes a LexA-repressed promoter .
The tum homologue of Fels-2 was responsible for lexA lethality and had a LexA-repressed promoter .
LexA protein represses the phage tum