Histone Acetyltransferase Activity of p300 Is Required for Transcriptional Repression by the Promyelocytic Leukemia Zinc Finger Protein

Fabien Guidez,Marek Cebrat,Melanie J Mcconnell,Mark Isalan,Philip A Cole,Sarah Ivins,Louise Howell,Jonathan Licht,Arthur Zelent,Sarah Pierce,Itsaso Hormaeche,Rhoda M Alani

doi:10.1128/mcb.25.13.5552-5566.2005

Abstract

Histone acetyltransferase (HAT) activities of proteins such as p300, CBP, and P/CAF play important roles in activation of gene expression. We now show that the HAT activity of p300 can also be required for down-regulation of transcription by a DNA binding repressor protein. Promyelocytic leukemia zinc finger (PLZF), originally identified as a fusion with retinoic acid receptor alpha in rare cases of all-trans-retinoic acid-resistant acute promyelocytic leukemia, is a transcriptional repressor that recruits histone deacetylase-containing corepressor complexes to specific DNA binding sites. PLZF associates with p300 in vivo, and its ability to repress transcription is specifically dependent on HAT activity of p300 and acetylation of lysines in its C-terminal C2-H2 zinc finger motif. An acetylation site mutant of PLZF does not repress transcription and is functionally deficient in a colony suppression assay despite retaining its abilities to interact with corepressor/histone deacetylase complexes. This is due to the fact that acetylation of PLZF activates its ability to bind specific DNA sequences both in vitro and in vivo. Taken together, our results indicate that a histone deacetylase-dependent transcriptional repressor can be positively regulated through acetylation and point to an unexpected role of a coactivator protein in transcriptional repression.

Highlights

Histone acetyltransferase (HAT) activities of proteins such as p300, CBP, and P/CAF play important roles in activation of gene expression
Given that the promyelocytic leukemia (PML) nuclear bodies may be associated with HAT activity and protein [22], for example in acetylation of p53 [63], we have sought to investigate whether Promyelocytic leukemia zinc finger (PLZF) could be a substrate for acetylation and what effect such a posttranslational modification would have on its function
Initial analysis of PLZF expressed endogenously in KG1 cells indicated that a fraction of the protein could be immunoprecipitated with anti-acetyl-lysine polyclonal antibody, suggesting that it exists in acetylated form (Fig. 1A, lane 1)

Summary

Introduction

Histone acetyltransferase (HAT) activities of proteins such as p300, CBP, and P/CAF play important roles in activation of gene expression. Promyelocytic leukemia zinc finger (PLZF), originally identified as a fusion with retinoic acid receptor alpha in rare cases of all-trans-retinoic acid-resistant acute promyelocytic leukemia, is a transcriptional repressor that recruits histone deacetylasecontaining corepressor complexes to specific DNA binding sites. PLZF associates with p300 in vivo, and its ability to repress transcription is dependent on HAT activity of p300 and acetylation of lysines in its C-terminal C2-H2 zinc finger motif. An acetylation site mutant of PLZF does not repress transcription and is functionally deficient in a colony suppression assay despite retaining its abilities to interact with corepressor/ histone deacetylase complexes This is due to the fact that acetylation of PLZF activates its ability to bind specific DNA sequences both in vitro and in vivo. An additional transcriptional repression domain, which binds the ETO protein and lies between the POZ domain and the zinc finger region, has been identified [58], and the first two zinc fingers of PLZF were found to be important for repression and activity of the chimeric PLZF-RAR␣ protein [14]

Methods

Results

Conclusion