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Antagonistic Gcn5-Hda1 interactions revealed by mutations to the Anaphase Promoting Complex in yeast.

Islam A, Turner EL, Menzel J, Malo ME, Harkness TA - Cell Div (2011)

Bottom Line: Occlusion of Gcn5 recruitment to these promoters involved Hda1 and Tup1.Our data suggests large Gcn5 and Hda1 containing complexes may compete for space on promoters that utilize the Ssn6/Tup1 repressor complex.We predict that in apc5CA cells the accumulation of an APC target may compensate for the loss of both GCN5 and HDA1.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK, S7N 5E5, Canada. troy.harkness@usask.ca.

ABSTRACT

Background: Histone post-translational modifications are critical for gene expression and cell viability. A broad spectrum of histone lysine residues have been identified in yeast that are targeted by a variety of modifying enzymes. However, the regulation and interaction of these enzymes remains relatively uncharacterized. Previously we demonstrated that deletion of either the histone acetyltransferase (HAT) GCN5 or the histone deacetylase (HDAC) HDA1 exacerbated the temperature sensitive (ts) mutant phenotype of the Anaphase Promoting Complex (APC) apc5CA allele. Here, the apc5CA mutant background is used to study a previously uncharacterized functional antagonistic genetic interaction between Gcn5 and Hda1 that is not detected in APC5 cells.

Results: Using Northerns, Westerns, reverse transcriptase PCR (rtPCR), chromatin immunoprecipitation (ChIP), and mutant phenotype suppression analysis, we observed that Hda1 and Gcn5 appear to compete for recruitment to promoters. We observed that the presence of Hda1 can partially occlude the binding of Gcn5 to the same promoter. Occlusion of Gcn5 recruitment to these promoters involved Hda1 and Tup1. Using sequential ChIP we show that Hda1 and Tup1 likely form complexes at these promoters, and that complex formation can be increased by deleting GCN5.

Conclusions: Our data suggests large Gcn5 and Hda1 containing complexes may compete for space on promoters that utilize the Ssn6/Tup1 repressor complex. We predict that in apc5CA cells the accumulation of an APC target may compensate for the loss of both GCN5 and HDA1.

No MeSH data available.


Related in: MedlinePlus

A model depicting potential interactions between Gcn5 and Hda1. (A) The HAT Gcn5 and the HDAC Hda1 have opposing functions that individually benefit APC function. (B) and (C) Gcn5 and Hda1 appear to compete for Tup1 binding. (B) If Hda1 first gains access to the promoter, recruitment of Gcn5 is partially blocked. (C) Under conditions where gene transcription must be derepressed, Tup1 may recruit Gcn5 to the promoter to prime transcriptional initiation, thus displacing Hda1. The protein labelled × represents a DNA binding factor that recruits the Tup1/Ssn6 corepressor complex to silent genes.
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Figure 8: A model depicting potential interactions between Gcn5 and Hda1. (A) The HAT Gcn5 and the HDAC Hda1 have opposing functions that individually benefit APC function. (B) and (C) Gcn5 and Hda1 appear to compete for Tup1 binding. (B) If Hda1 first gains access to the promoter, recruitment of Gcn5 is partially blocked. (C) Under conditions where gene transcription must be derepressed, Tup1 may recruit Gcn5 to the promoter to prime transcriptional initiation, thus displacing Hda1. The protein labelled × represents a DNA binding factor that recruits the Tup1/Ssn6 corepressor complex to silent genes.

Mentions: Taken together, the results presented in this report suggest a competitive interaction can occur between Hda1/Tup1 and Gcn5 at promoters (Figure 8). Our results suggest that the presence of Hda1/Tup1 (and likely Ssn6) occludes, at least partially, the recruitment of Gcn5 to some promoters. Gcn5, on the other hand, may impede Tup1-Hda1 interactions by competing for Tup1 binding. It is possible that the gcn5Δ/hda1Δ genetic interaction is prominent in apc5CA cells due to the accumulation of an APC target, perhaps another HAT, capable of suppressing gcn5 hda1Δ impairments.


Antagonistic Gcn5-Hda1 interactions revealed by mutations to the Anaphase Promoting Complex in yeast.

Islam A, Turner EL, Menzel J, Malo ME, Harkness TA - Cell Div (2011)

A model depicting potential interactions between Gcn5 and Hda1. (A) The HAT Gcn5 and the HDAC Hda1 have opposing functions that individually benefit APC function. (B) and (C) Gcn5 and Hda1 appear to compete for Tup1 binding. (B) If Hda1 first gains access to the promoter, recruitment of Gcn5 is partially blocked. (C) Under conditions where gene transcription must be derepressed, Tup1 may recruit Gcn5 to the promoter to prime transcriptional initiation, thus displacing Hda1. The protein labelled × represents a DNA binding factor that recruits the Tup1/Ssn6 corepressor complex to silent genes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3141613&req=5

Figure 8: A model depicting potential interactions between Gcn5 and Hda1. (A) The HAT Gcn5 and the HDAC Hda1 have opposing functions that individually benefit APC function. (B) and (C) Gcn5 and Hda1 appear to compete for Tup1 binding. (B) If Hda1 first gains access to the promoter, recruitment of Gcn5 is partially blocked. (C) Under conditions where gene transcription must be derepressed, Tup1 may recruit Gcn5 to the promoter to prime transcriptional initiation, thus displacing Hda1. The protein labelled × represents a DNA binding factor that recruits the Tup1/Ssn6 corepressor complex to silent genes.
Mentions: Taken together, the results presented in this report suggest a competitive interaction can occur between Hda1/Tup1 and Gcn5 at promoters (Figure 8). Our results suggest that the presence of Hda1/Tup1 (and likely Ssn6) occludes, at least partially, the recruitment of Gcn5 to some promoters. Gcn5, on the other hand, may impede Tup1-Hda1 interactions by competing for Tup1 binding. It is possible that the gcn5Δ/hda1Δ genetic interaction is prominent in apc5CA cells due to the accumulation of an APC target, perhaps another HAT, capable of suppressing gcn5 hda1Δ impairments.

Bottom Line: Occlusion of Gcn5 recruitment to these promoters involved Hda1 and Tup1.Our data suggests large Gcn5 and Hda1 containing complexes may compete for space on promoters that utilize the Ssn6/Tup1 repressor complex.We predict that in apc5CA cells the accumulation of an APC target may compensate for the loss of both GCN5 and HDA1.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK, S7N 5E5, Canada. troy.harkness@usask.ca.

ABSTRACT

Background: Histone post-translational modifications are critical for gene expression and cell viability. A broad spectrum of histone lysine residues have been identified in yeast that are targeted by a variety of modifying enzymes. However, the regulation and interaction of these enzymes remains relatively uncharacterized. Previously we demonstrated that deletion of either the histone acetyltransferase (HAT) GCN5 or the histone deacetylase (HDAC) HDA1 exacerbated the temperature sensitive (ts) mutant phenotype of the Anaphase Promoting Complex (APC) apc5CA allele. Here, the apc5CA mutant background is used to study a previously uncharacterized functional antagonistic genetic interaction between Gcn5 and Hda1 that is not detected in APC5 cells.

Results: Using Northerns, Westerns, reverse transcriptase PCR (rtPCR), chromatin immunoprecipitation (ChIP), and mutant phenotype suppression analysis, we observed that Hda1 and Gcn5 appear to compete for recruitment to promoters. We observed that the presence of Hda1 can partially occlude the binding of Gcn5 to the same promoter. Occlusion of Gcn5 recruitment to these promoters involved Hda1 and Tup1. Using sequential ChIP we show that Hda1 and Tup1 likely form complexes at these promoters, and that complex formation can be increased by deleting GCN5.

Conclusions: Our data suggests large Gcn5 and Hda1 containing complexes may compete for space on promoters that utilize the Ssn6/Tup1 repressor complex. We predict that in apc5CA cells the accumulation of an APC target may compensate for the loss of both GCN5 and HDA1.

No MeSH data available.


Related in: MedlinePlus