The C terminus of the alpha subunit of RNA polymerase is not essential for transcriptional activation of sigma 54 holoenzyme - PubMed (original) (raw)

The C terminus of the alpha subunit of RNA polymerase is not essential for transcriptional activation of sigma 54 holoenzyme

H S Lee et al. J Bacteriol. 1993 Apr.

Abstract

Several activators of sigma 70 holoenzyme whose binding sites lie upstream of the -35 region of promoters require the C-terminal region of the alpha subunit of RNA polymerase to activate transcription. (These are among class I activators, which require the C-terminal region of the alpha subunit for transcription activation.) Because transcription by sigma 54 holoenzyme universally depends upon activators whose binding sites lie well upstream (or downstream) of promoters, we determined whether the C-terminal region of the alpha subunit was also required for transcription from the sigma 54-dependent promoter for the glnA operon. Nitrogen regulatory protein C-dependent activation from the glnA promoter remained good when RNA polymerases containing C-terminal truncations of the alpha subunit were employed. This was also the case for nitrogen fixation protein A-dependent activation if a nitrogen fixation protein A-binding site was appropriately placed upstream of the glnA promoter. These results lead to the working hypothesis (as yet untested) that activators of sigma 54 holoenzyme, which appear to make direct physical contact with the polymerase to catalyze a change in its conformation, activate the sigma 54 holoenzyme by contacting the sigma subunit rather than the alpha subunit of the core enzyme.

PubMed Disclaimer

Cited by

Genetic regulation of nitrogen fixation in rhizobia.
Fischer HM. Fischer HM. Microbiol Rev. 1994 Sep;58(3):352-86. doi: 10.1128/mr.58.3.352-386.1994. Microbiol Rev. 1994. PMID: 7968919 Free PMC article. Review.
Identification of close contacts between the sigma N (sigma 54) protein and promoter DNA in closed promoter complexes.
Cannon W, Austin S, Moore M, Buck M. Cannon W, et al. Nucleic Acids Res. 1995 Feb 11;23(3):351-6. doi: 10.1093/nar/23.3.351. Nucleic Acids Res. 1995. PMID: 7885829 Free PMC article.
The C-terminal region of the alpha subunit of Escherichia coli RNA polymerase is required for transcriptional activation of the flagellar level II operons by the FlhD/FlhC complex.
Liu X, Fujita N, Ishihama A, Matsumura P. Liu X, et al. J Bacteriol. 1995 Sep;177(17):5186-8. doi: 10.1128/jb.177.17.5186-5188.1995. J Bacteriol. 1995. PMID: 7665504 Free PMC article.
The TyrR protein of Escherichia coli is a class I transcription activator.
Lawley B, Fujita N, Ishihama A, Pittard AJ. Lawley B, et al. J Bacteriol. 1995 Jan;177(1):238-41. doi: 10.1128/jb.177.1.238-241.1995. J Bacteriol. 1995. PMID: 7798138 Free PMC article.

References

1. Annu Rev Genet. 1979;13:59-97 - PubMed
1. Nucleic Acids Res. 1993 Jan 25;21(2):319-26 - PubMed
1. Nature. 1983 Jan 27;301(5898):307-13 - PubMed
1. J Mol Biol. 1984 Dec 25;180(4):881-909 - PubMed
1. Nucleic Acids Res. 1985 Nov 11;13(21):7607-20 - PubMed

The C terminus of the alpha subunit of RNA polymerase is not essential for transcriptional activation of sigma 54 holoenzyme - PubMed (original) (raw)