ZIC2-dependent transcriptional regulation is mediated by DNA-dependent protein kinase, poly(ADP-ribose) polymerase, and RNA helicase A.
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.
Ishiguro
Akira
A
Laboratory for Comparative Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan. Electronic address: akiraishiguro@brain.riken.go.jp.
Ideta
Maki
M
Laboratory for Comparative Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan.
Mikoshiba
Katsuhiko
K
Laboratory of Developmental Neurobiology, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan.
Chen
David J
DJ
Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 75390.
Aruga
Jun
J
Laboratory for Comparative Neurogenesis, RIKEN Brain Science Institute, Wako-shi, Saitama 351-0198, Japan. Electronic address: jaruga@brain.riken.go.jp.
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
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