Protein lysine 43 methylation by EZH1 promotes AML1-ETO transcriptional repression in leukemia

Liping Dou,Chongjian Chen,Yihan Xu,Aref Al‐Kali ,Puja Singh,Yvchi Gao,Li Gao,Young In ,Mark R Litzow,Lili Wang,Shujun Liu,Lei Zhou,Tao Liu,Jianxin Shi ,Lijun Wang,Dandan Li,Yonghui Li,Jiuxia Pang,Guido Marcucci,Na Shen,Haojie Huang,Chunhui Liu,Daoyuan Zheng ,Dai‐Hong Liu ,Qian Wang,Fei Yan,Ann M Bode,Li Yu

doi:10.1038/s41467-019-12960-6

Abstract

The oncogenic fusion protein AML1-ETO retains the ability of AML1 to interact with the enhancer core DNA sequences, but blocks AML1-dependent transcription. Previous studies have shown that post-translational modification of AML1-ETO may play a role in its regulation. Here we report that AML1-ETO-positive patients, with high histone lysine methyltransferase Enhancer of zeste homolog 1 (EZH1) expression, show a worse overall survival than those with lower EZH1 expression. EZH1 knockdown impairs survival and proliferation of AML1-ETO-expressing cells in vitro and in vivo. We find that EZH1 WD domain binds to the AML1-ETO NHR1 domain and methylates AML1-ETO at lysine 43 (Lys43). This requires the EZH1 SET domain, which augments AML1-ETO-dependent repression of tumor suppressor genes. Loss of Lys43 methylation by point mutation or domain deletion impairs AML1-ETO-repressive activity. These findings highlight the role of EZH1 in non-histone lysine methylation, indicating that cooperation between AML1-ETO and EZH1 and AML1-ETO site-specific lysine methylation promote AML1-ETO transcriptional repression in leukemia.

Highlights

The oncogenic fusion protein AML1-ETO retains the ability of AML1 to interact with the enhancer core DNA sequences, but blocks AML1-dependent transcription
Enhancer of zeste homolog 1 (EZH1) upregulation predicts worse prognosis in AML1-ETO acute myeloid leukemia (AML). Their functional abnormalities are strongly associated with many types of cancer27, whether or how EZH1/2 regulates AML1-ETO leukemia remains elusive
We showed that the NHR1 domain of AML1-ETO directly interacts with the WD domain of EZH1, and that this protein interaction is required for EZH1 to methylate AML1-ETO lysine 43 (Lys43)

Summary

Introduction

The oncogenic fusion protein AML1-ETO retains the ability of AML1 to interact with the enhancer core DNA sequences, but blocks AML1-dependent transcription. AML1-ETO retains the ability of AML1 to interact with the enhancer core DNA sequence, but blocks AML1-dependent transcription1–4 It activates certain genes, AML1-ETO dominantly represses AML1 targets, leading to perturbation of normal hematopoiesis. AML1-ETO recruits copartners (e.g., HDACs, DNMTs, and p300) to target promoters resulting in gene repression/activation It still remains largely unknown how AML1-ETO interacts with diverse transcriptional factors and target DNAs. Previous studies showed that p300 acetylates AML1-ETO at lysine 43 (Lys43) enhancing AML1-ETO functions. EZH1 possesses lower histone lysine methyltransferase activity compared to EZH226, which is further supported by a recent study showing that EZH1 knockdown in mice has a limited effect on global trimethylation of H3K2727 These findings support the idea that EZH1 could regulate genes in a histone methylationindependent manner, which has not been explored. We demonstrate that Lys methylation by EZH1 is critical means of AML1-ETO-driven transcription

Methods

Results

Conclusion