Lysogeny maintenance and termination

(a) A homodimeric repressor protein binds to 17-bp operator sequences to regulate its own transcription and maintain lysogeny. (b) UV light and other DNA-damaging agents activate RecA, which cleaves l repressor monomers to inactivate repressor protein. (c) Lysogeny ends with the removal of l repressor protein from operator sequences and the initiation of transcription of cro(a) A homodimeric repressor protein binds to 17-bp operator sequences to regulate its own transcription and maintain lysogeny. (b) UV light and other DNA-damaging agents activate RecA, which cleaves l repressor monomers to inactivate repressor protein. (c) Lysogeny ends with the removal of l repressor protein from operator sequences and the initiation of transcription of cro

(a) Repressor Repressor monomer dimer Amino acids (inactive) (active) 132—236 (b) Inactive UV— Activated ReCA damaged RGCA \b (C) cro transcription