Transcription factor βγ(RAP30/74) from rat liver was previously shown in biochemical studies to control the binding of RNA polymerase II to promoters by a mechanism analogous to that utilized by bacterial σ factors, by decreasing the affinity of polymerase for nonpromoter sites on DNA and by increasing the affinity of the enzyme for the preinitiation complex (Conaway, R. C., Garrett, K. P., Hanley, J. P., and Conaway, J. W. (1991) Proc. Natl. Acad. Sci. U. S. A. 88, 6205-6209). By constructing and analyzing mutants of βγ, we have identified a novel functional domain located in the carboxyl terminus of the γ(RAP30) subunit. This domain shares sequence similarity with region 4 of bacterial σ factors; in particular, it exhibits striking similarity to the carboxyl-terminal regions 4.1 and 4.2 of SpoIIIC (Bacillus subtilis σk). Evidence from biochemical studies argues that a mutant γ(RAPSO), lacking amino acid sequences similar to σ homology region 4.2, is able to assemble with the β(RAP74) subunit to form a mutant βγ(RAP30/74) with impaired ability to interact with RNA polymerase II.
|Original language||English (US)|
|Number of pages||8|
|Journal||Journal of Biological Chemistry|
|State||Published - Nov 25 1992|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology