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Molecular and Cellular Biology, November 2001, p. 7331-7344, Vol. 21, No. 21
Department of Biochemistry and Molecular
Biology, Pennsylvania State University, University Park,
Pennsylvania 16802-4500
Received 15 June 2001/Returned for modification 19 July
2001/Accepted 30 July 2001
Yeast TAF90p is a component of at least two transcription
regulatory complexes, the general transcription factor TFIID and the
Spt-Ada-Gcn5 histone acetyltransferase complex (SAGA). Broad transcription defects have been observed in mutants of other
TAFIIs shared by TFIID and SAGA but not in the only two
TAF90 mutants isolated to date. Given that the numbers
of mutants analyzed thus far are small, we isolated and characterized
11 temperature-sensitive mutants of TAF90 and analyzed
their effects on transcription and integrity of the TFIID and SAGA
complexes. We found that the mutants displayed a variety of
allele-specific defects in their ability to support transcription and
maintain the structure of the TFIID and SAGA complexes. Sequencing of
the alleles revealed that all have mutations corresponding to
the C terminus of the protein, with most clustering within the
conserved WD40 repeats; thus, the C terminus of TAF90p is required for
its incorporation into TFIID and function in SAGA. Significantly,
inactivation of one allele, taf90-20, caused the
dramatic reduction in the levels of total mRNA and most specific
transcripts analyzed. Analysis of the structure and/or activity of both
TAF90p-containing complexes revealed that this allele is the most
disruptive of all. Our analysis defines the requirement for the WD40
repeats in preserving TFIID and SAGA function, demonstrates that the
defects associated with distinct mutations in TAF90 vary
considerably, and indicates that TAF90 can be classified
as a gene required for the transcription of a large number of genes.
0270-7306/01/$04.00+0 DOI: 10.1128/MCB.21.21.7331-7344.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Analysis of TAF90 Mutants Displaying
Allele-Specific and Broad Defects in Transcription
*
Corresponding author. Mailing address: Department of
Biochemistry and Molecular Biology, Pennsylvania State University, 203 Althouse Laboratory, University Park, PA 16802-4500. Phone: (814) 865-1976. Fax: (814) 863-7024. E-mail: jcr8{at}psu.edu.
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