Previous Article | Next Article ![]()
Mol Cell Biol, May 1998, p. 2650-2658, Vol. 18, No. 5
UPR 9002 du CNRS "Structure des
Macromolécules Biologiques et Mécanismes de
Reconnaissance," IBMC, 67084 Strasbourg Cedex, France
Received 16 October 1997/Returned for modification 24 November
1997/Accepted 17 February 1998
Staf is a transcriptional activator of prime importance for
enhanced transcription of small nuclear (snRNA) and snRNA-type genes
transcribed by RNA polymerases II and III (Pol II and III). In addition
to this activity, it also possesses the capacity to stimulate
expression from an RNA polymerase II mRNA promoter. This
promiscuous activator thus provides a useful model system for studying
the mechanism by which one single transcription factor can
activate a large variety of promoters. Here, we report the use of in
vivo assays to identify the Staf activation domains involved in
promoter selectivity. Analysis of Staf mutants reveals the existence of
two physically and functionally distinct regions, outside of the DNA
binding domain, responsible for mediating selective transcriptional
activation. While a 93-amino-acid domain, with the striking presence of
four repeated units, is specialized for transcriptional activation of
an mRNA promoter, a segment of only 18 amino acids, with a critical
Leu-213 residue, acts specifically on Pol II and Pol III snRNA and
snRNA-type promoters. In addition, this study disclosed the
fundamental importance of invariant leucine and aspartic acid residues
located in each repeat unit of the mRNA activation domain. Staf is
therefore the first transcriptional activator described so far
to harbor two physically and functionally distinct activator domains.
This finding suggests that the same activator can contact different,
specialized transcription complexes formed on different types of basal
promoters through promoter-specific transactivation pathways.
0270-7306/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Two Distinct Domains in Staf To Selectively
Activate Small Nuclear RNA-Type and mRNA Promoters
*
Corresponding author. Mailing address: UPR 9002 du CNRS
"Structure des Macromolécules Biologiques et Mécanismes
de Reconnaissance," IBMC, 15, rue René Descartes, 67084 Strasbourg Cedex, France. Phone: (33) 3.88.41.70.50. Fax: (33)
3.88.60.22.18. E-mail: p.carbon{at}ibmc.u-strasbg.fr.
This article has been cited by other articles:
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|