GSBS Student Publications


The effects of mutations in the ant promoter of phage P22 depend on context

GSBS Program

Biochemistry & Molecular Pharmacology

UMMS Affiliation

Graduate School of Biomedical Sciences; Department of Molecular Genetics and Microbiology



Document Type


Medical Subject Headings

Base Sequence; Cloning, Molecular; *Genes, Viral; *Mutation; Plasmids; *Promoter Regions (Genetics); Recombination, Genetic; Salmonella Phages; beta-Galactosidase


Life Sciences | Medicine and Health Sciences


Recombination was used to construct 22 two- or three-way combinations of down- and up-mutations in Pant, a strong, near-consensus promoter of phage P22. The relative strengths of these promoters in vivo were assayed by fusing them to an ant/lacZ gene fusion and measuring beta-galactosidase levels produced by lysogens carrying the fusions on single-copy prophages. The results of these assays show that the magnitude of the effect of a promoter mutation can vary considerably when its context is changed by the presence of another mutation. In addition, as Pant approaches conformity with the consensus promoter sequence, the up-mutations decrease promoter strength, even though the same mutations increase promoter strength in the presence of a down-mutation. These context effects imply that individual consensus base pairs cannot be considered to contribute to promoter strength independently.

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Citation: Genetics. 1988 Oct;120(2):319-27.

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Link to article in PubMed

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