scholarly journals Maximal Stimulation of Meiotic Recombination by a Yeast Transcription Factor Requires the Transcription Activation Domain and a DNA-Binding Domain

Genetics ◽  
1999 ◽  
Vol 152 (1) ◽  
pp. 101-115 ◽  
Author(s):  
David T Kirkpatrick ◽  
Qingqing Fan ◽  
Thomas D Petes

Abstract The DNA sequences located upstream of the yeast HIS4 represent a very strong meiotic recombination hotspot. Although the activity of this hotspot requires the transcription activator Rap1p, the level of HIS4 transcription is not directly related to the level of recombination. We find that the recombination-stimulating activity of Rap1p requires the transcription activation domain of the protein. We show that a hybrid protein with the Gal4p DNA-binding domain and the Rap1p activation domain can stimulate recombination in a strain in which Gal4p-binding sites are inserted upstream of HIS4. In addition, we find recombination hotspot activity associated with the Gal4p DNA-binding sites that is independent of known transcription factors. We suggest that yeast cells have two types of recombination hotspots, α (transcription factor dependent) and β (transcription factor independent).

Genetics ◽  
1988 ◽  
Vol 120 (1) ◽  
pp. 63-74
Author(s):  
M Johnston ◽  
J Dover

Abstract The GAL4 protein of Saccharomyces cerevisiae binds to DNA upstream of each of six genes and stimulates their transcription. To locate regions of the protein responsible for these processes, we identified and characterized 88 gal4 mutations selected in vivo to reduce the ability to GAL4 protein to activate transcription. These mutations alter two regions of GAL4 protein: the DNA binding domain, and the transcription activation domain. Some mutations in the DNA binding domain that abolish the ability of GAL4 protein to bind to DNA in vitro change amino acid residues proposed to form a zinc finger, confirming that this structure is indeed involved in DNA binding. Four different amino acid changes in the zinc finger appear to reduce (but not abolish) the affinity of GAL4 protein for zinc ions, thereby identifying some of the amino acids involved in forming the zinc-binding structure. Several other mutations that abolish the DNA binding activity of the protein alter the 20 amino acids adjacent to the zinc finger, suggesting that these residues are part of the DNA binding domain. Two amino acid changes in the region adjacent to the zinc finger also appear to affect the ability of GAL4 protein to bind zinc ions, suggesting that this region of the protein can influence the structure of the zinc binding domain. The transcription activation domain of GAL4 protein is remarkably resistant to single amino acid changes: only 4 of the 42 mutations that alter this region of the protein are of the missense type. This observation is consistent with other lines of evidence that GAL4 protein possesses multiple transcription activation domains with unusual sequence flexibility.


1998 ◽  
Vol 18 (7) ◽  
pp. 4197-4208 ◽  
Author(s):  
Kannan Thirunavukkarasu ◽  
Muktar Mahajan ◽  
Keith W. McLarren ◽  
Stefano Stifani ◽  
Gerard Karsenty

ABSTRACT Osf2/Cbfa1, hereafter called Osf2, is a member of the Runt-related family of transcription factors that plays a critical role during osteoblast differentiation. Like all Runt-related proteins, it contains a runt domain, which is the DNA-binding domain, and a C-terminal proline-serine-threonine-rich (PST) domain thought to be the transcription activation domain. Additionally, Osf2 has two amino-terminal domains distinct from any other Runt-related protein. To understand the mechanisms of osteoblast gene regulation by Osf2, we performed an extensive structure-function analysis. After defining a short Myc-related nuclear localization signal, a deletion analysis revealed the existence of three transcription activation domains and one repression domain. AD1 (for activation domain 1) comprises the first 19 amino acids of the molecule, which form the first domain unique to Osf2, AD2 is formed by the glutamine-alanine (QA) domain, the second domain unique to Osf2, and AD3 is located in the N-terminal half of the PST domain and also contains sequences unique to Osf2. The transcription repression domain comprises the C-terminal 154 amino acids of Osf2. DNA-binding, domain-swapping, and protein interaction experiments demonstrated that full-length Osf2 does not interact with Cbfβ, a known partner of Runt-related proteins, whereas a deletion mutant of Osf2 containing only the runt and PST domains does. The QA domain appears to be responsible for preventing this heterodimerization. Thus, our results uncover the unique functional organization of Osf2 by identifying functional domains not shared with other Runt-related proteins that largely control its transactivation and heterodimerization abilities.


1995 ◽  
Vol 15 (8) ◽  
pp. 4319-4330 ◽  
Author(s):  
J Zuo ◽  
D Rungger ◽  
R Voellmy

Upon heat stress, monomeric human heat shock transcription factor 1 (hHSF1) is converted to a trimer, acquires DNA-binding ability, is transported to the nucleus, and becomes transcriptionally competent. It was not known previously whether these regulatory changes are caused by a single activation event or whether they occur independently from one another, providing a multilayered control that may prevent inadvertant activation of hHSF1. Comparison of wild-type and mutant hHSF1 expressed in Xenopus oocytes and human HeLa cells suggested that retention of hHSF1 in the monomeric form depends on hydrophobic repeats (LZ1 to LZ3) and a carboxy-terminal sequence element in hHSF1 as well as on the presence of a titratable factor in the cell. Oligomerization of hHSF1 appears to induce DNA-binding activity as well as to uncover an amino-terminally located nuclear localization signal. A mechanism distinct from that controlling oligomerization regulates the transcriptional competence of hHSF1. Components of this mechanism were mapped to a region, including LZ2 and nearby sequences downstream from LZ2, that is clearly separated from the carboxy-terminally located transcription activation domain(s). We propose the existence of a fold-back structure that masks the transcription activation domain in the unstressed cell but is opened up by modification of hHSF1 and/or binding of a factor facilitating hHSF1 unfolding in the stressed cell. Activation of hHSF1 appears to involve at least two independently regulated structural transitions.


1992 ◽  
Vol 12 (1) ◽  
pp. 266-275 ◽  
Author(s):  
J J Schwarz ◽  
T Chakraborty ◽  
J Martin ◽  
J M Zhou ◽  
E N Olson

Myogenin is a skeletal muscle-specific transcription factor that can activate myogenesis when introduced into a variety of nonmuscle cell types. Activation of the myogenic program by myogenin is dependent on its binding to a DNA sequence known as an E box, which is associated with numerous muscle-specific genes. Myogenin shares homology with MyoD and other myogenic regulatory factors within a basic region and a helix-loop-helix (HLH) motif that mediate DNA binding and dimerization, respectively. Here we show that the basic region-HLH motif of myogenin alone lacks transcriptional activity and is dependent on domains in the amino and carboxyl termini to activate transcription. Analysis of these N- and C-terminal domains through creation of chimeras with the DNA-binding domain of the Saccharomyces cerevisiae transcription factor GAL4 revealed that they act as strong transcriptional activators. These transcription activation domains are dependent for activity on a specific amino acid sequence within the basic region, referred to as the myogenic recognition motif (MRM), when an E box is the target for DNA binding. However, the activation domains function independent of the MRM when DNA binding is mediated through a heterologous DNA-binding domain. The activation domain of the acidic coactivator VP16 can substitute for the myogenin activation domains and restore strong myogenic activity to the basic region-HLH motif. Within a myogenin-VP16 chimera, however, the VP16 activation domain also relies on the MRM for activation of the myogenic program. These findings reveal that DNA binding and transcriptional activation are separable functions, encoded by different domains of myogenin, but that the activity of the transcriptional activation domains is influenced by the DNA-binding domain. Activation of muscle-specific transcription requires collaboration between the DNA-binding and activation domains of myogenin and is dependent on events in addition to DNA binding.


2009 ◽  
Vol 29 (23) ◽  
pp. 6283-6293 ◽  
Author(s):  
Uschi Lindert ◽  
Mirjam Cramer ◽  
Michael Meuli ◽  
Oleg Georgiev ◽  
Walter Schaffner

ABSTRACT Metal-responsive transcription factor 1 (MTF-1) mediates both basal and heavy metal-induced transcription of metallothionein genes and also regulates other genes involved in the cell stress response and in metal homeostasis. In resting cells, MTF-1 localizes to both the cytoplasm and the nucleus but quantitatively accumulates in the nucleus upon metal load and under other stress conditions. Here we show that within the DNA-binding domain, a region spanning zinc fingers 1 to 3 (amino acids [aa] 137 to 228 in human MTF-1) harbors a nonconventional nuclear localization signal. This protein segment confers constitutive nuclear localization to a cytoplasmic marker protein. The deletion of the three zinc fingers impairs nuclear localization. The export of MTF-1 to the cytoplasm is controlled by a classical nuclear export signal (NES) embedded in the acidic activation domain. We show that this activation domain confers metal inducibility in distinct cell types when fused to a heterologous DNA-binding domain. Furthermore, the cause of a previously described stronger inducibility of human versus mouse MTF-1 could be narrowed down to a 3-aa difference in the NES; “humanizing” mouse MTF-1 at these three positions enhanced its metal inducibility to the level of human MTF-1.


1992 ◽  
Vol 12 (1) ◽  
pp. 266-275
Author(s):  
J J Schwarz ◽  
T Chakraborty ◽  
J Martin ◽  
J M Zhou ◽  
E N Olson

Myogenin is a skeletal muscle-specific transcription factor that can activate myogenesis when introduced into a variety of nonmuscle cell types. Activation of the myogenic program by myogenin is dependent on its binding to a DNA sequence known as an E box, which is associated with numerous muscle-specific genes. Myogenin shares homology with MyoD and other myogenic regulatory factors within a basic region and a helix-loop-helix (HLH) motif that mediate DNA binding and dimerization, respectively. Here we show that the basic region-HLH motif of myogenin alone lacks transcriptional activity and is dependent on domains in the amino and carboxyl termini to activate transcription. Analysis of these N- and C-terminal domains through creation of chimeras with the DNA-binding domain of the Saccharomyces cerevisiae transcription factor GAL4 revealed that they act as strong transcriptional activators. These transcription activation domains are dependent for activity on a specific amino acid sequence within the basic region, referred to as the myogenic recognition motif (MRM), when an E box is the target for DNA binding. However, the activation domains function independent of the MRM when DNA binding is mediated through a heterologous DNA-binding domain. The activation domain of the acidic coactivator VP16 can substitute for the myogenin activation domains and restore strong myogenic activity to the basic region-HLH motif. Within a myogenin-VP16 chimera, however, the VP16 activation domain also relies on the MRM for activation of the myogenic program. These findings reveal that DNA binding and transcriptional activation are separable functions, encoded by different domains of myogenin, but that the activity of the transcriptional activation domains is influenced by the DNA-binding domain. Activation of muscle-specific transcription requires collaboration between the DNA-binding and activation domains of myogenin and is dependent on events in addition to DNA binding.


Biochemistry ◽  
2004 ◽  
Vol 43 (51) ◽  
pp. 16027-16035 ◽  
Author(s):  
Shinichiro Oka ◽  
Yasuhisa Shiraishi ◽  
Takuya Yoshida ◽  
Tadayasu Ohkubo ◽  
Yukio Sugiura ◽  
...  

1996 ◽  
Vol 236 (3) ◽  
pp. 911-921 ◽  
Author(s):  
Jurgen Schultheiss ◽  
Olaf Kunert ◽  
Uwe Gase ◽  
Klaus-Dieter Scharf ◽  
Lutz Nover ◽  
...  

1994 ◽  
Vol 14 (9) ◽  
pp. 6056-6067
Author(s):  
M Tanaka ◽  
W Herr

The POU domain activator Oct-2 contains an N-terminal glutamine-rich transcriptional activation domain. An 18-amino-acid segment (Q18III) from this region reconstituted a fully functional activation domain when tandemly reiterated and fused to either the Oct-2 or GAL4 DNA-binding domain. A minimal transcriptional activation domain likely requires three tandem Q18III segments, because one or two tandem Q18III segments displayed little activity, whereas three to five tandem segments were active and displayed increasing activity with increasing copy number. As with natural Oct-2 activation domains, in our assay a reiterated activation domain required a second homologous or heterologous activation domain to stimulate transcription effectively when fused to the Oct-2 POU domain. These results suggest that there are different levels of synergy within and among activation domains. Analysis of reiterated activation domains containing mutated Q18III segments revealed that leucines and glutamines, but not serines or threonines, are critical for activity in vivo. Curiously, several reiterated activation domains that were inactive in vivo were active in vitro, suggesting that there are significant functional differences in our in vivo and in vitro assays. Reiteration of a second 18-amino-acid segment from the Oct-2 glutamine-rich activation domain (Q18II) was also active, but its activity was DNA-binding domain specific, because it was active when fused to the GAL4 than to the Oct-2 DNA-binding domain. The ability of separate short peptide segments derived from a single transcriptional activation domain to activate transcription after tandem reiteration emphasizes the flexible and modular nature of a transcriptional activation domain.


2017 ◽  
Author(s):  
Jungeui Hong ◽  
Nathan Brandt ◽  
Ally Yang ◽  
Tim Hughes ◽  
David Gresham

Understanding the molecular basis of gene expression evolution is a central problem in evolutionary biology. However, connecting changes in gene expression to increased fitness, and identifying the functional basis of those changes, remains challenging. To study adaptive evolution of gene expression in real time, we performed long term experimental evolution (LTEE) of Saccharomyces cerevisiae (budding yeast) in ammonium-limited chemostats. Following several hundred generations of continuous selection we found significant divergence of nitrogen-responsive gene expression in lineages with increased fitness. In multiple independent lineages we found repeated selection for non-synonymous mutations in the zinc finger DNA binding domain of the activating transcription factor (TF), GAT1, that operates within incoherent feedforward loops to control expression of the nitrogen catabolite repression (NCR) regulon. Missense mutations in the DNA binding domain of GAT1 reduce its binding affinity for the GATAA consensus sequence in a promoter-specific manner, resulting in increased expression of ammonium permease genes via both direct and indirect effects, thereby conferring increased fitness. We find that altered transcriptional output of the NCR regulon results in antagonistic pleiotropy in alternate environments and that the DNA binding domain of GAT1 is subject to purifying selection in natural populations. Our study shows that adaptive evolution of gene expression can entail tuning expression output by quantitative changes in TF binding affinities while maintaining the overall topology of a gene regulatory network.


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