The Effects of Mutations in the Ant Promoter of Phage P22 Depend on Context

AUTOR(ES)

Grana, D.

RESUMO

Recombination was used to construct 22 two- or three-way combinations of down- and up-mutations in P(ant), 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 β-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 P(ant) 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.

Documentos Relacionados

• Mutations That Improve the ANT Promoter of Salmonella Phage P22
• Hierarchies of base pair preferences in the P22 ant promoter.
• The Circularity of the Phage P22 Linkage Map
• Genetic analysis of the Rhizobium meliloti nifH promoter, using the P22 challenge phage system.
• Conformational transformations in the protein lattice of phage P22 procapsids.