title: Identification of RANBP16 and RANBP17 as novel interaction partners for the bHLH transcription factor E12.
abstract: The ubiquitously expressed basic helix-loop-helix (bHLH) transcription factors E12 and E47, products of alternative splicing of the E2A/TCF3 gene, regulate diverse biological processes including cell growth, differentiation and development. To search for novel protein interactions for E12, we utilized the bHLH domain of E12 as a bait in yeast two-hybrid screening. Yeast two-hybrid, mammalian two-hybrid, and co-immunoprecipitation analyses demonstrate specific interaction of E12 with RANBP17, a novel member of the importin-beta superfamily; this interaction maps to the CRM1 homology region of RANBP17. Ectopic expression of RANBP17 leads to a approximately 3-fold increase in E2A/MyoD mediated transactivation of an E-box regulated luciferase reporter gene. Interaction and transactivation studies also revealed similar functions for RANBP16/XPO7. Furthermore, ectopic expression of either RANBP16 or RANBP17 resulted in increased level of endogenous transcript for the cyclin-dependent kinase inhibitor, p21(Waf1/Cip1), a well-characterized E2A target gene. Together, these biochemical and functional data reveal RANBP16 and RANBP17 as novel regulators of E2A protein action.
authors.affiliation: Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine, Toledo, Ohio 43614, USA.
authors.forename: Jun-Ho
authors.initials: JH
authors.lastname: Lee
authors.forename: Shengli
authors.initials: S
authors.lastname: Zhou
authors.forename: Cynthia M
authors.initials: CM
authors.lastname: Smas
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D017930:Genes, Reporter; D006367:HeLa Cells; D006801:Humans; D028884:Karyopherins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D058127:Transcription Factor 3 / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D020798:Two-Hybrid System Techniques; D020931:ran GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D028884:Karyopherins; C417256:RanGTP-binding protein 16; C417257:RanGTP-binding protein 17; D058127:Transcription Factor 3; C000589007:XPO7 protein, human; D020931:ran GTP-Binding Protein