title: AML1-ETO decreases ETO-2 (MTG16) interactions with nuclear receptor corepressor, an effect that impairs granulocyte differentiation.
abstract: The t(8;21) chromosome abnormality in acute myeloid leukemia targets the AML1 and ETO genes to produce the leukemia fusion protein AML1-ETO. Another member of the ETO family, ETO-2/MTG16, is highly expressed in murine and human hematopoietic cells, bears >75% homology to ETO, and like ETO, contains a conserved MYND domain that interacts with the nuclear receptor corepressor (N-CoR). AML1-ETO prevents granulocyte but not macrophage differentiation of murine 32Dcl3 granulocyte/macrophage progenitors. One possible mechanism is recruitment of N-CoR to aberrantly repress AML1 target genes. We wished to examine another mechanism by which AML1-ETO might impair granulocyte differentiation. We demonstrate that AML1-ETO decreases interactions between ETO-2 and N-CoR. Furthermore, overexpression of ETO-2 relieves AML1-ETO-induced granulocyte differentiation arrest. This suggests that decreased interactions between ETO-2 and N-CoR may contribute to granulocyte differentiation impairment. The MYND domain coimmunoprecipitates with N-CoR and inhibits interactions between ETO-2 and N-CoR, presumably by occupying the ETO-2 binding site on N-CoR. This inhibition of ETO-2 interactions with N-CoR is specific because the MYND domain does not inhibit retinoic acid receptor interactions with N-CoR. To examine the effect of decreasing interactions between ETO-2 and N-CoR in hematopoietic cells, without effects of AML1-ETO such as direct repression of AML1 target genes, the MYND domain was expressed in 32Dcl3 and human CD34+ cells. The MYND domain prevented granulocyte but not macrophage differentiation of both 32Dcl3 and human CD34+ cells, recapitulating this effect of AML1-ETO. In conclusion, decreasing interactions between ETO-2 and N-CoR, an effect of AML1-ETO, inhibits granulocyte differentiation.
authors.affiliation: Section of Hematology/Oncology, Department of Medicine, University of Illinois, Chicago, USA.
authors.forename: Vinzon
authors.initials: V
authors.lastname: Ibañez
authors.forename: Arun
authors.initials: A
authors.lastname: Sharma
authors.forename: Silvia
authors.initials: S
authors.lastname: Buonamici
authors.forename: Amit
authors.initials: A
authors.lastname: Verma
authors.forename: Sudhakar
authors.initials: S
authors.lastname: Kalakonda
authors.forename: Jianxiang
authors.initials: J
authors.lastname: Wang
authors.forename: ShriHari
authors.initials: S
authors.lastname: Kadkol
authors.forename: Yogen
authors.initials: Y
authors.lastname: Saunthararajah
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D050676:Core Binding Factor Alpha 2 Subunit; D005312:Fetal Blood / Q000166:cytology; D006098:Granulocytes / Q000166:cytology / Q000378:metabolism*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D008264:Macrophages / Q000166:cytology / Q000378:metabolism; D051379:Mice; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D056971:Nuclear Receptor Co-Repressor 1; D015514:Oncogene Proteins, Fusion / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D010446:Peptide Fragments / Q000096:biosynthesis / Q000235:genetics; D010750:Phosphoproteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D000075142:RUNX1 Translocation Partner 1 Protein; D012097:Repressor Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D014162:Transfection; D025521:Tumor Suppressor Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: C107844:AML1-ETO fusion protein, human; C115744:CBFA2T3 protein, human; C117411:Cbfa2t3 protein, mouse; D050676:Core Binding Factor Alpha 2 Subunit; C539127:NCOR1 protein, human; C539128:Ncor1 protein, mouse; D009687:Nuclear Proteins; D056971:Nuclear Receptor Co-Repressor 1; D015514:Oncogene Proteins, Fusion; D010446:Peptide Fragments; D010750:Phosphoproteins; D000075142:RUNX1 Translocation Partner 1 Protein; D012097:Repressor Proteins; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins