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Revision as of 16:47, 3 March 2012
- Midhat Patel 15:50, 27 February 2012 (EST): Can sigma factors be used to regulate gene expression? If we use a promoter associated with a sigma factor that operates under specific conditions, can it be used as a promoter for a system and integrated into E. coli?
- Yi Kou 10:07, 3 March 2012 (EST): Good idea! Here is one paper of similar "genetic transplantation" of sigma factor. But I think for actual application, it is not so simple as one factor and binding sequence could do the work. Many regulations, involving posttranslational regulation and auto-regulation have been confirmed for many types of sigma factors. And if these accompanies are not well considered, I think it would be hard to observe the expected result or phenotype. Also, it has been suggested that the sigma factor is not "on and off" the core pol but rather shows a "self-changing" pattern associated with the RNA pol. This might add another influence of "interaction spectrum" with this sigma factor "transplantation" idea.
- Jeffrey E. Barrick 11:16, 3 March 2012 (EST):How did they create the "insulator" sequence that didn't have any known transcription factor binding sites? Did they make it up from scratch, or did they grab it from somewhere else in a different genome?
- Karlinsey JE and Hughes KT. . pmid:16352826.
- Mukhopadhyay J, Kapanidis AN, Mekler V, Kortkhonjia E, Ebright YW, and Ebright RH. . pmid:11525731.
- Burgess-Beusse B, Farrell C, Gaszner M, Litt M, Mutskov V, Recillas-Targa F, Simpson M, West A, and Felsenfeld G. . pmid:12154228.
- Ben Slater 15:47, 3 March 2012 (EST): In your section on promoters, you say "there has not been a promoter found in E. coli that is of the consensus sequence, it would likely bind so strongly that elongation would not occur." Since transcription rate increases as the promoter approaches the consensus sequence, but plummets if it actually IS the consensus sequence, where is the cutoff? Will only 1 bp difference be the optimal rate?