title: Fusion proteins of the retinoic acid receptor-alpha recruit histone deacetylase in promyelocytic leukaemia.
abstract: The transforming proteins of acute promyelocytic leukaemias (APL) are fusions of the promyelocytic leukaemia (PML) and the promyelocytic leukaemia zinc-finger (PLZF) proteins with retinoic acid receptor-alpha (RARalpha). These proteins retain the RARalpha DNA- and retinoic acid (RA)-binding domains, and their ability to block haematopoietic differentiation depends on the RARalpha DNA-binding domain. Thus RA-target genes are downstream effectors. However, treatment with RA induces differentiation of leukaemic blast cells and disease remission in PML-RARalpha APLs, whereas PLZF-RARa APLs are resistant to RA. Transcriptional regulation by RARs involves modifications of chromatin by histone deacetylases, which are recruited to RA-target genes by nuclear co-repressors. Here we show that both PML-RARalpha and PLZF-RARalpha fusion proteins recruit the nuclear co-repressor (N-CoR)-histone deacetylase complex through the RARalpha CoR box. PLZF-RARalpha contains a second, RA-resistant binding site in the PLZF amino-terminal region. High doses of RA release histone deacetylase activity from PML-RARalpha, but not from PLZF-RARalpha. Mutation of the N-CoR binding site abolishes the ability of PML-RARalpha to block differentiation, whereas inhibition of histone deacetylase activity switches the transcriptional and biological effects of PLZF-RARalpha from being an inhibitor to an activator of the RA signalling pathway. Therefore, recruitment of histone deacetylase is crucial to the transforming potential of APL fusion proteins, and the different effects of RA on the stability of the PML-RARalpha and PLZF-RARalpha co-repressor complexes determines the differential response of APLs to RA.
authors.affiliation: Istituto di Medicina Interna e Scienze Oncologiche, Perugia University, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Grignani
authors.forename: S
authors.initials: S
authors.lastname: De Matteis
authors.forename: C
authors.initials: C
authors.lastname: Nervi
authors.forename: L
authors.initials: L
authors.lastname: Tomassoni
authors.forename: V
authors.initials: V
authors.lastname: Gelmetti
authors.forename: M
authors.initials: M
authors.lastname: Cioce
authors.forename: M
authors.initials: M
authors.lastname: Fanelli
authors.forename: M
authors.initials: M
authors.lastname: Ruthardt
authors.forename: F F
authors.initials: FF
authors.lastname: Ferrara
authors.forename: I
authors.initials: I
authors.lastname: Zamir
authors.forename: C
authors.initials: C
authors.lastname: Seiser
authors.forename: F
authors.initials: F
authors.lastname: Grignani
authors.forename: M A
authors.initials: MA
authors.lastname: Lazar
authors.forename: S
authors.initials: S
authors.lastname: Minucci
authors.forename: P G
authors.initials: PG
authors.lastname: Pelicci
mesh_terms: D001665:Binding Sites; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases / Q000235:genetics / Q000502:physiology*; D006877:Hydroxamic Acids / Q000494:pharmacology; D015473:Leukemia, Promyelocytic, Acute / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D016296:Mutagenesis; D009363:Neoplasm Proteins / Q000235:genetics / Q000502:physiology*; D009687:Nuclear Proteins / Q000235:genetics / Q000502:physiology; D056971:Nuclear Receptor Co-Repressor 1; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000502:physiology*; D011485:Protein Binding; D018168:Receptors, Retinoic Acid / Q000235:genetics / Q000502:physiology*; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology; D000072482:Retinoic Acid Receptor alpha; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D014212:Tretinoin / Q000494:pharmacology; D025521:Tumor Suppressor Proteins
chemical_list: D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D056971:Nuclear Receptor Co-Repressor 1; D015514:Oncogene Proteins, Fusion; D018168:Receptors, Retinoic Acid; D012097:Repressor Proteins; D000072482:Retinoic Acid Receptor alpha; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; C012589:trichostatin A; D014212:Tretinoin; D006655:Histone Deacetylases