Abstract
We have shown previously that the cII gene product of the non-lambdoid temperate bacteriophage 186 is required for the establishment of lysogeny. We show here that CII, a potential helix-turn-helix DNA-binding protein, establishes lysogeny by activating a promoter (PE) which spans the apl/cII intergenic region, upstream of the lysogenic promoter, PL. The start site of the PE transcript (+1) has been mapped by primer extension and we have identified the CII binding determinants at PE by DNase I footprinting. CII binds to inverted repeat sequences separated by two turns of the helix, with binding half-sites centred at the 38 and -58 positions of PE. Oligomerisation studies with purified CII protein indicate that a CII tetramer may be the species that binds to this site. We also show that PE is subject to direct negative feedback by the CI repressor.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Base Sequence
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Binding Sites
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Coliphages / genetics*
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DNA Footprinting
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DNA, Viral / chemistry
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DNA, Viral / metabolism
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DNA-Binding Proteins*
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Lysogeny / genetics*
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Molecular Sequence Data
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Molecular Weight
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Nucleic Acid Conformation
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Promoter Regions, Genetic / genetics*
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Protein Conformation
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RNA, Messenger / genetics
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RNA, Viral / genetics
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Repetitive Sequences, Nucleic Acid / genetics
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Repressor Proteins / metabolism
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Transcription Factors / chemistry
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Transcription Factors / metabolism*
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Transcriptional Activation / genetics*
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Viral Proteins
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Viral Regulatory and Accessory Proteins
Substances
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DNA, Viral
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DNA-Binding Proteins
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RNA, Messenger
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RNA, Viral
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Repressor Proteins
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Transcription Factors
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Viral Proteins
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Viral Regulatory and Accessory Proteins
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cII protein, bacteriophage lambda
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phage repressor proteins