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The 19S proteasome subcomplex promotes the targeting of NuA4 HAT to the promoters of ribosomal protein genes to facilitate the recruitment of TFIID for transcriptional initiation in vivo.

Uprety B, Lahudkar S, Malik S, Bhaumik SR - Nucleic Acids Res. (2011)

Bottom Line: These observations support that the 19S proteasome subcomplex enhances the targeting of co-activator at the TFIID-dependent promoter.Such an enhanced targeting of NuA4 HAT (histone acetyltransferase) promotes the recruitment of the TFIID complex for transcriptional initiation.Collectively, our data demonstrate that the 19S proteasome subcomplex enhances the targeting of NuA4 HAT to activator Rap1p at the promoters of ribosomal protein genes to facilitate the recruitment of TFIID for transcriptional stimulation, hence providing a new role of the 19S proteasome subcomplex in establishing a specific regulatory network at the TFIID-dependent promoter for productive transcriptional initiation in vivo.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Southern Illinois University-School of Medicine, Carbondale, IL 62901, USA.

ABSTRACT
Previous studies have implicated SAGA (Spt-Ada-Gcn5-acetyltransferase) and TFIID (Transcription factor-IID)-dependent mechanisms of transcriptional activation in yeast. SAGA-dependent transcriptional activation is further regulated by the 19S proteasome subcomplex. However, the role of the 19S proteasome subcomplex in transcriptional activation of the TFIID-dependent genes has not been elucidated. Therefore, we have performed a series of chromatin immunoprecipitation, mutational and transcriptional analyses at the TFIID-dependent ribosomal protein genes such as RPS5, RPL2B and RPS11B. We find that the 19S proteasome subcomplex is recruited to the promoters of these ribosomal protein genes, and promotes the association of NuA4 (Nucleosome acetyltransferase of histone H4) co-activator, but not activator Rap1p (repressor-activator protein 1). These observations support that the 19S proteasome subcomplex enhances the targeting of co-activator at the TFIID-dependent promoter. Such an enhanced targeting of NuA4 HAT (histone acetyltransferase) promotes the recruitment of the TFIID complex for transcriptional initiation. Collectively, our data demonstrate that the 19S proteasome subcomplex enhances the targeting of NuA4 HAT to activator Rap1p at the promoters of ribosomal protein genes to facilitate the recruitment of TFIID for transcriptional stimulation, hence providing a new role of the 19S proteasome subcomplex in establishing a specific regulatory network at the TFIID-dependent promoter for productive transcriptional initiation in vivo.

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Analysis of recruitment of Rap1p and NuA4 HAT (Esa1p-myc) to the RPS5 promoter in the wild-type and rpt4-ts mutant strains following ts inactivation of Rpt4p at 37°C for 1 h. Immunoprecipitations were performed as described in Figures 3A and B.
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gkr977-F5: Analysis of recruitment of Rap1p and NuA4 HAT (Esa1p-myc) to the RPS5 promoter in the wild-type and rpt4-ts mutant strains following ts inactivation of Rpt4p at 37°C for 1 h. Immunoprecipitations were performed as described in Figures 3A and B.

Mentions: So far, it is clear that Rap1p, NuA4 HAT and 19S base play crucial roles to recruit TFIID for transcriptional initiation of RPS5. However, the specific regulatory network of these factors at the RPS5 promoter is not known. It has been demonstrated previously that the 19S base enhances the targeting of SAGA HAT co-activator to the activator Gal4p at the SAGA-dependent GAL1 gene for transcriptional initiation of GAL1 (35,36). Based on these results, we hypothesize that the 19S base might be similarly enhancing the targeting of NuA4 HAT to the activator Rap1p at the RPS5 UAS to facilitate the recruitment of TFIID for transcriptional initiation. To test this possibility, we analyzed the recruitment of Rap1p and NuA4 HAT to the RPS5 UAS in the wild-type and ts mutant strains of the Rpt4p ATPase component of the 19S base. If the 19S base increases the targeting of NuA4 HAT to Rap1p at the RPS5 UAS, we would observe a significant decrease in the recruitment of NuA4 HAT, but not Rap1p, at the RPS5 UAS in the rpt4-ts mutant strain as compared with the wild-type equivalent. Indeed, we find that Rap1p recruitment to the RPS5 UAS was not altered in the rpt4-ts mutant strain (Figure 5). However, the recruitment of NuA4 HAT (Esa1p-Myc) to the RPS5 UAS was significantly impaired in the rpt4-ts mutant strain (Figure 5). These results strongly support that the 19S base facilitates the targeting of NuA4 HAT to Rap1p at the RPS5 UAS. This observation is remarkably consistent with previous studies (35,36) that demonstrated the role of the 19S base in enhancing the targeting of SAGA HAT to the activator Gal4p at the SAGA-dependent GAL1 gene. Although previous studies (35,36) have shown the role of the 19S base in targeting SAGA to the SAGA-dependent gene, the role of the 19S base at the promoter of the TFIID-dependent gene remained unknown. This study demonstrates for the first time the role of the 19S base in enhanced targeting of NuA4 HAT to the activator of a TFIID-dependent ribosomal protein gene, RPS5 (Figure 5), and subsequently facilitates the recruitment of the TFIID complex for transcriptional initiation (Figure 4A and B).Figure 5.


The 19S proteasome subcomplex promotes the targeting of NuA4 HAT to the promoters of ribosomal protein genes to facilitate the recruitment of TFIID for transcriptional initiation in vivo.

Uprety B, Lahudkar S, Malik S, Bhaumik SR - Nucleic Acids Res. (2011)

Analysis of recruitment of Rap1p and NuA4 HAT (Esa1p-myc) to the RPS5 promoter in the wild-type and rpt4-ts mutant strains following ts inactivation of Rpt4p at 37°C for 1 h. Immunoprecipitations were performed as described in Figures 3A and B.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3300024&req=5

gkr977-F5: Analysis of recruitment of Rap1p and NuA4 HAT (Esa1p-myc) to the RPS5 promoter in the wild-type and rpt4-ts mutant strains following ts inactivation of Rpt4p at 37°C for 1 h. Immunoprecipitations were performed as described in Figures 3A and B.
Mentions: So far, it is clear that Rap1p, NuA4 HAT and 19S base play crucial roles to recruit TFIID for transcriptional initiation of RPS5. However, the specific regulatory network of these factors at the RPS5 promoter is not known. It has been demonstrated previously that the 19S base enhances the targeting of SAGA HAT co-activator to the activator Gal4p at the SAGA-dependent GAL1 gene for transcriptional initiation of GAL1 (35,36). Based on these results, we hypothesize that the 19S base might be similarly enhancing the targeting of NuA4 HAT to the activator Rap1p at the RPS5 UAS to facilitate the recruitment of TFIID for transcriptional initiation. To test this possibility, we analyzed the recruitment of Rap1p and NuA4 HAT to the RPS5 UAS in the wild-type and ts mutant strains of the Rpt4p ATPase component of the 19S base. If the 19S base increases the targeting of NuA4 HAT to Rap1p at the RPS5 UAS, we would observe a significant decrease in the recruitment of NuA4 HAT, but not Rap1p, at the RPS5 UAS in the rpt4-ts mutant strain as compared with the wild-type equivalent. Indeed, we find that Rap1p recruitment to the RPS5 UAS was not altered in the rpt4-ts mutant strain (Figure 5). However, the recruitment of NuA4 HAT (Esa1p-Myc) to the RPS5 UAS was significantly impaired in the rpt4-ts mutant strain (Figure 5). These results strongly support that the 19S base facilitates the targeting of NuA4 HAT to Rap1p at the RPS5 UAS. This observation is remarkably consistent with previous studies (35,36) that demonstrated the role of the 19S base in enhancing the targeting of SAGA HAT to the activator Gal4p at the SAGA-dependent GAL1 gene. Although previous studies (35,36) have shown the role of the 19S base in targeting SAGA to the SAGA-dependent gene, the role of the 19S base at the promoter of the TFIID-dependent gene remained unknown. This study demonstrates for the first time the role of the 19S base in enhanced targeting of NuA4 HAT to the activator of a TFIID-dependent ribosomal protein gene, RPS5 (Figure 5), and subsequently facilitates the recruitment of the TFIID complex for transcriptional initiation (Figure 4A and B).Figure 5.

Bottom Line: These observations support that the 19S proteasome subcomplex enhances the targeting of co-activator at the TFIID-dependent promoter.Such an enhanced targeting of NuA4 HAT (histone acetyltransferase) promotes the recruitment of the TFIID complex for transcriptional initiation.Collectively, our data demonstrate that the 19S proteasome subcomplex enhances the targeting of NuA4 HAT to activator Rap1p at the promoters of ribosomal protein genes to facilitate the recruitment of TFIID for transcriptional stimulation, hence providing a new role of the 19S proteasome subcomplex in establishing a specific regulatory network at the TFIID-dependent promoter for productive transcriptional initiation in vivo.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Southern Illinois University-School of Medicine, Carbondale, IL 62901, USA.

ABSTRACT
Previous studies have implicated SAGA (Spt-Ada-Gcn5-acetyltransferase) and TFIID (Transcription factor-IID)-dependent mechanisms of transcriptional activation in yeast. SAGA-dependent transcriptional activation is further regulated by the 19S proteasome subcomplex. However, the role of the 19S proteasome subcomplex in transcriptional activation of the TFIID-dependent genes has not been elucidated. Therefore, we have performed a series of chromatin immunoprecipitation, mutational and transcriptional analyses at the TFIID-dependent ribosomal protein genes such as RPS5, RPL2B and RPS11B. We find that the 19S proteasome subcomplex is recruited to the promoters of these ribosomal protein genes, and promotes the association of NuA4 (Nucleosome acetyltransferase of histone H4) co-activator, but not activator Rap1p (repressor-activator protein 1). These observations support that the 19S proteasome subcomplex enhances the targeting of co-activator at the TFIID-dependent promoter. Such an enhanced targeting of NuA4 HAT (histone acetyltransferase) promotes the recruitment of the TFIID complex for transcriptional initiation. Collectively, our data demonstrate that the 19S proteasome subcomplex enhances the targeting of NuA4 HAT to activator Rap1p at the promoters of ribosomal protein genes to facilitate the recruitment of TFIID for transcriptional stimulation, hence providing a new role of the 19S proteasome subcomplex in establishing a specific regulatory network at the TFIID-dependent promoter for productive transcriptional initiation in vivo.

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