title: The LAZ3(BCL-6) oncoprotein recruits a SMRT/mSIN3A/histone deacetylase containing complex to mediate transcriptional repression.
abstract: Recent works demonstrated that some transcriptional repressors recruit histone deacetylases (HDACs) either through direct interaction, or as a member of a multisubunit repressing complex containing other components referred to as corepressors. For instance, the bHLH-Zip transcriptional repressors MAD/MXI recruit HDACs together with the mSIN3 corepressors, whereas unliganded nuclear receptors contact another corepressor, SMRT (or its relative N-CoR), which, in turn, associates with both mSIN3 and HDACs to form the repressor complex. Recently, we reported that SMRT also directly associates with LAZ3(BCL-6), a POZ/Zn finger transcriptional repressor involvedin the pathogenesis of non-Hodgkin lymphomas. However, whether LAZ3 recruits the HDACs-containing repression complex is currently unknown. We report here that LAZ3 associates with corepressor mSIN3A both in vivo and in vitro , and found that a central region, which harbours autonomous repression activity, is mainly responsible for this interaction. Conversely, the N-terminal half of mSIN3A is both necessary and sufficient to bind LAZ3. Moreover, we show that LAZ3 also interacts with an HDAC (HDAC-1) through its POZ domain in vitro while the immunoprecipitation of LAZ3 results in the coretention of an endogenous HDAC activity in vivo . Finally, inhibitors of HDACs significantly reduce the LAZ3-mediated repression. Taken together, we conclude that LAZ3 recruits a repressing complex containing SMRT, mSIN3A and a HDAC, and that its full repressing potential on transcription requires HDACs activity. Our results identify HDACs as molecular targets of LAZ3 oncogene and further strengthen the connection between aberrant chromatin acetylation and human cancers.
authors.affiliation: U124 INSERM/IRCL, Place de Verdun, F-59045 Lille cedex, France and Howard Hughes Medical Institute and The Salk Institute for Biological Studies, La Jolla, CA 92037, USA. dhordain@infobiogen.fr
authors.forename: P
authors.initials: P
authors.lastname: Dhordain
authors.forename: R J
authors.initials: RJ
authors.lastname: Lin
authors.forename: S
authors.initials: S
authors.lastname: Quief
authors.forename: D
authors.initials: D
authors.lastname: Lantoine
authors.forename: J P
authors.initials: JP
authors.lastname: Kerckaert
authors.forename: R M
authors.initials: RM
authors.lastname: Evans
authors.forename: O
authors.initials: O
authors.lastname: Albagli
mesh_terms: D000107:Acetylation; D015153:Blotting, Western; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D056284:Histone Deacetylase 1; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases / Q000378:metabolism*; D006801:Humans; D056985:Nuclear Receptor Co-Repressor 2; D011233:Precipitin Tests; D011485:Protein Binding; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D051560:Proto-Oncogene Proteins c-bcl-6; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion / Q000235:genetics; D056264:Sin3 Histone Deacetylase and Corepressor Complex; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D016335:Zinc Fingers
chemical_list: C084103:BCL6 protein, human; D004268:DNA-Binding Proteins; D056572:Histone Deacetylase Inhibitors; C539130:NCOR2 protein, human; D056985:Nuclear Receptor Co-Repressor 2; D011518:Proto-Oncogene Proteins; D051560:Proto-Oncogene Proteins c-bcl-6; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; C099683:SIN3A transcription factor; D014157:Transcription Factors; C110550:HDAC1 protein, human; D056284:Histone Deacetylase 1; D006655:Histone Deacetylases; D056264:Sin3 Histone Deacetylase and Corepressor Complex