Journal of Microbiology

P22-Based Challenge Phage Constructs to Study DNA-Protein Interactions between the [sigma]^54-Dependent Promoter, dctA, and Its Transcriptional Regulators: Eungbin Kim , Daeyou Kim , Joon Haeng Lee; J. Microbiol. 2000;38(3):176-179.

Abstract: A challenge phage system was used to study the DNA-protein interaction between C_4 -dicarboylic acid transport protein D (DCTD) or [sigma]^54 , and a [sigma]^54 -dependent promoter, dctAp. R. meliloti dctA promoter regulatory region replaced the O_mnt site on the phage. S. typhimurium strains overproducing either DCTD or [sigma]^54 directed this challenge phage towards lysogeny, indicating that DCTD or E[sigma]^54 recognized the dctA promoter on the phage and repressed transcription of the ant gene. These challenge phage constructs will be useful for examining interactions between DCTD (or [sigma]^54 ) and the dctA promoter region.

P22-Based Challenge Phage Constructs to Study Protein-Protein Interactions between the [sigma]^54 -Dependent Promoter, dctA, and Its Transcriptional Regulators: Jeong Min Song , Eungbin Kim , Joon H. Lee; J. Microbiol. 2002;40(3):205-210.

Abstract: To study interactions between C_4 -dicarboxylic acid transport protein D and E[sigma]^54 in the dctA promoter regulatory region, we used the challenge phage system. An ant'-'lac fusion was recombined onto the challenge phage, and this ant'-'lac fusion along with Pant and the R. meliloti dctA promoter regulatory region were cloned onto a plasmid. The plasmid bearing the ant'-'lac fusion was used as a reporter plasmid in a coupled transcription-translation system. Addition of purified [sigma]^54 to the coupled system specifically repressed transcription of the plasmid-borne ant'-'lac fusion. When DCTD was added along with [sigma]^54 to the coupled system, transcription of the ant'-'lac fusion was even further repressed, suggesting that DCTD may stabilize closed complexes between E[sigma]^54 and the dctA promoter.

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