title: ZIC2-dependent transcriptional regulation is mediated by DNA-dependent protein kinase, poly(ADP-ribose) polymerase, and RNA helicase A.
abstract: The Zic family of zinc finger proteins is essential for animal development, as demonstrated by the holoprosencephaly caused by mammalian Zic2 mutation. To determine the molecular mechanism of Zic-mediated developmental control, we characterized two types of high molecular weight complexes, including Zic2. Complex I was composed of DNA-dependent protein kinase catalytic subunit (DNA-PKcs), Ku70/80, and poly(ADP-ribose) polymerase; complex II contained Ku70/80 and RNA helicase A; all the components interacted directly with Zic2 protein. Immunoprecipitation, subnuclear localization, and in vitro phosphorylation analyses revealed that the DNA-PKcs in complex I played an essential role in the assembly of complex II. Stepwise exchange from complex I to complex II depended on phosphorylation of Zic2 by DNA-PK and poly-(ADP-ribose) polymerase. Phosphorylated Zic2 protein made a stable complex with RNA helicase A, and complex II could interact with RNA polymerase II. Phosphorylation-dependent transformation of Zic2-containing molecular complexes may occur in transcriptional regulation.
authors.affiliation: Laboratory for Comparative Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan. Electronic address: akiraishiguro@brain.riken.go.jp.
authors.forename: Akira
authors.initials: A
authors.lastname: Ishiguro
authors.affiliation: Laboratory for Comparative Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Ideta
authors.affiliation: Laboratory of Developmental Neurobiology, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Mikoshiba
authors.affiliation: Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 75390.
authors.forename: David J
authors.initials: DJ
authors.lastname: Chen
authors.affiliation: Laboratory for Comparative Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan. Electronic address: jaruga@brain.riken.go.jp.
authors.forename: Jun
authors.initials: J
authors.lastname: Aruga
mesh_terms: D002460:Cell Line; D053487:DEAD-box RNA Helicases / Q000378:metabolism / Q000502:physiology*; D051747:DNA-Activated Protein Kinase / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D009363:Neoplasm Proteins / Q000378:metabolism / Q000502:physiology*; D009687:Nuclear Proteins / Q000378:metabolism / Q000502:physiology*; D010766:Phosphorylation; D011065:Poly(ADP-ribose) Polymerases / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism / Q000502:physiology*; D014158:Transcription, Genetic / Q000502:physiology
chemical_list: D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors; C491812:ZIC2 protein, human; D011065:Poly(ADP-ribose) Polymerases; D051747:DNA-Activated Protein Kinase; C098487:DHX9 protein, human; D053487:DEAD-box RNA Helicases