title: SUMO modification of NZFP mediates transcriptional repression through TBP binding.
abstract: The negatively regulating zinc finger protein (NZFP) is an essential transcription repressor required for early development during gastrulation in Xenopus laevis. In this study, we found that NZFP interacts with the small ubiquitin-like modifier (SUMO) conjugation E2 enzyme, Ubc9, and contains three putative SUMO conjugation sites. Studies with NZFP mutants containing mutations at the putative SUMO conjugation sites showed that these sites were able to be modified independently with SUMO. NZFP was found to be localized in the same nuclear bodies with SUMO-1. However, sumoylation of NZFP did not play a role either in the translocation of NZFP into the nucleus or on nuclear body formation. While wild type NZFP showed significant transcriptional repression, SUMO-conjugation site mutants manifested a decrease in transcriptional repression activity which is reversely proportional to the amount of sumoylation. The sumoylation defective mutant lost its TBP binding activity, while wild type NZFP interacted with TBP and inhibited transcription complex formation. These results strongly suggest that the sumoylation of NZFP facilitates NZFP to bind to TBP and the NZFP/TBP complex then represses the transcription of the target gene by inhibiting basal transcription complex formation.
authors.affiliation: School of Biological Sciences, Institute of Molecular Biology and Genetics, Seoul National University, Seoul 151-742, Korea.
authors.forename: Mijin
authors.initials: M
authors.lastname: Kim
authors.forename: Zifan
authors.initials: Z
authors.lastname: Chen
authors.forename: Myoung Sup
authors.initials: MS
authors.lastname: Shim
authors.forename: Myoung Sook
authors.initials: MS
authors.lastname: Lee
authors.forename: Ji Eon
authors.initials: JE
authors.lastname: Kim
authors.forename: Young Eun
authors.initials: YE
authors.lastname: Kwon
authors.forename: Tack Jin
authors.initials: TJ
authors.lastname: Yoo
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Kim
authors.forename: Je Young
authors.initials: JY
authors.lastname: Bang
authors.forename: Bradley A
authors.initials: BA
authors.lastname: Carlson
authors.forename: Jae Hong
authors.initials: JH
authors.lastname: Seol
authors.forename: Dolph L
authors.initials: DL
authors.lastname: Hatfield
authors.forename: Byeong Jae
authors.initials: BJ
authors.lastname: Lee
mesh_terms: D000818:Animals; D015153:Blotting, Western; D019556:COS Cells; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D025842:SUMO-1 Protein / Q000235:genetics / Q000378:metabolism*; D058207:Sumoylation; D035181:TATA-Box Binding Protein / Q000378:metabolism*; D014158:Transcription, Genetic; D020798:Two-Hybrid System Techniques; D014982:Xenopus laevis
chemical_list: D011994:Recombinant Proteins; D012097:Repressor Proteins; D025842:SUMO-1 Protein; D035181:TATA-Box Binding Protein; C476235:ZNF182 protein, Xenopus