|
|
|
Research Papers
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
Abstract
The expression of the yeast CYC1 and CYC7 genes is controlled by the HAP1 activator. A GAL4-like zinc finger (residues 1-148) specifies binding to the dissimilar sites UAS1 (of CYC1) and CYC7, and an acidic domain (residues 1307-1483) is essential for activation of transcription. To analyze how HAP1 binds to UAS1 and CYC7, we performed saturation mutagenesis of the DNA-binding domain and recovered mutants with altered activity. Class 1 mutants had a reduced activity at both UAS1 and CYC7, and class 2 mutants selectively eliminated activity at CYC7. Surprisingly, several mutants of both classes exhibited wild-type DNA binding, indicating that they were specifically defective in activation. These positive control (PC) mutants alter residues that bracket the zinc finger. We explain these mutants in a model involving cofactor proteins that bind UAS1 and CYC7 along with HAP1. The existence of PC mutants that only affect activity at CYC7 raises the possibility that different cofactors may exist for UAS1 and CYC7.
This article has been cited by other articles:
![]() |
T. Hon, H. C. Lee, Z. Hu, V. R. Iyer, and L. Zhang The Heme Activator Protein Hap1 Represses Transcription by a Heme-Independent Mechanism in Saccharomyces cerevisiae Genetics, March 1, 2005; 169(3): 1343 - 1352. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Lan, H. C. Lee, S. Tang, and L. Zhang A Novel Mode of Chaperone Action: HEME ACTIVATION OF Hap1 BY ENHANCED ASSOCIATION OF Hsp90 WITH THE REPRESSED Hsp70-Hap1 COMPLEX J. Biol. Chem., June 25, 2004; 279(26): 27607 - 27612. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Hon, A. Dodd, R. Dirmeier, N. Gorman, P. R. Sinclair, L. Zhang, and R. O. Poyton A Mechanism of Oxygen Sensing in Yeast: MULTIPLE OXYGEN-RESPONSIVE STEPS IN THE HEME BIOSYNTHETIC PATHWAY AFFECT Hap1 ACTIVITY J. Biol. Chem., December 12, 2003; 278(50): 50771 - 50780. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. C. Lee, T. Hon, C. Lan, and L. Zhang Structural Environment Dictates the Biological Significance of Heme-Responsive Motifs and the Role of Hsp90 in the Activation of the Heme Activator Protein Hap1 Mol. Cell. Biol., August 15, 2003; 23(16): 5857 - 5866. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. C. Lee, T. Hon, and L. Zhang The Molecular Chaperone Hsp90 Mediates Heme Activation of the Yeast Transcriptional Activator Hap1 J. Biol. Chem., February 22, 2002; 277(9): 7430 - 7437. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Hon, H. C. Lee, A. Hach, J. L. Johnson, E. A. Craig, H. Erdjument-Bromage, P. Tempst, and L. Zhang The Hsp70-Ydj1 Molecular Chaperone Represses the Activity of the Heme Activator Protein Hap1 in the Absence of Heme Mol. Cell. Biol., December 1, 2001; 21(23): 7923 - 7932. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. K. Lukens, D. A. King, and R. Marmorstein Structure of HAP1-PC7 bound to DNA: implications for DNA recognition and allosteric effects of DNA-binding on transcriptional activation Nucleic Acids Res., October 15, 2000; 28(20): 3853 - 3863. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Ha, K. Hellauer, and B. Turcotte Fusions with histone H3 result in highly specific alteration of gene expression Nucleic Acids Res., February 15, 2000; 28(4): 1026 - 1035. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Hach, T. Hon, and L. Zhang The Coiled Coil Dimerization Element of the Yeast Transcriptional Activator Hap1, a Gal4 Family Member, Is Dispensable for DNA Binding but Differentially Affects Transcriptional Activation J. Biol. Chem., January 7, 2000; 275(1): 248 - 254. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Hon, A. Hach, D. Tamalis, Y. Zhu, and L. Zhang The Yeast Heme-responsive Transcriptional Activator Hap1 Is a Preexisting Dimer in the Absence of Heme J. Biol. Chem., August 6, 1999; 274(32): 22770 - 22774. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Hach, T. Hon, and L. Zhang A New Class of Repression Modules Is Critical for Heme Regulation of the Yeast Transcriptional Activator Hap1 Mol. Cell. Biol., June 1, 1999; 19(6): 4324 - 4333. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Zhang, A. Hach, and C. Wang Molecular Mechanism Governing Heme Signaling in Yeast: a Higher-Order Complex Mediates Heme Regulation of the Transcriptional Activator HAP1 Mol. Cell. Biol., July 1, 1998; 18(7): 3819 - 3828. [Abstract] [Full Text] |
||||
![]() |
L Zhang and L Guarente The yeast activator HAP1--a GAL4 family member--binds DNA in a directly repeated orientation. Genes & Dev., September 1, 1994; 8(17): 2110 - 2119. [Abstract] [PDF] |
||||
![]() |
R. Reece and M Ptashne Determinants of binding-site specificity among yeast C6 zinc cluster proteins Science, August 13, 1993; 261(5123): 909 - 911. [Abstract] [PDF] |
||||