title: A novel role of the actin-nucleating Arp2/3 complex in the regulation of RNA polymerase II-dependent transcription.
abstract: It has been well documented that actin is present in the nucleus and involved in numerous nuclear functions including regulation of transcription. The actin-nucleating Arp2/3 complex is an essential, evolutionarily conserved seven-subunit protein complex that promotes actin cytoskeleton assembly in the cytoplasm upon stimulation by WASP family proteins. Our recent study indicates that the nuclear localized neural Wiskott-Aldrich syndrome protein (N-WASP) can induce de novo actin polymerization in the nucleus, and this function is important for the role of N-WASP in the regulation of RNA polymerase II-dependent transcription. Here, we have presented evidence to show that the Arp2/3 complex is also localized in the nucleus and plays an essential role in mediating nuclear actin polymerization induced by N-WASP. We have also demonstrated that the Arp2/3 complex physically associates with RNA polymerase II and is involved in the RNA polymerase II-dependent transcriptional regulation both in vivo and in vitro. Together, these data provide strong support for the hypothesis that N-WASP and the Arp2/3 complex regulate transcription, at least in part, through the regulation of nuclear actin polymerization in a manner similar to their function in the cytoplasm.
authors.affiliation: Department of Molecular Medicine, Cornell University, Ithaca, New York 14853, USA.
authors.forename: Youngdong
authors.initials: Y
authors.lastname: Yoo
authors.forename: Xiaoyang
authors.initials: X
authors.lastname: Wu
authors.forename: Jun-Lin
authors.initials: JL
authors.lastname: Guan
mesh_terms: D051376:Actin-Related Protein 2-3 Complex / Q000502:physiology*; D000199:Actins / Q000378:metabolism; D021581:Active Transport, Cell Nucleus; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D006801:Humans; D012319:RNA Polymerase II / Q000502:physiology*; D034741:RNA, Small Interfering / Q000494:pharmacology; D014158:Transcription, Genetic; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal / Q000502:physiology
chemical_list: D051376:Actin-Related Protein 2-3 Complex; D000199:Actins; D034741:RNA, Small Interfering; C495771:WASL protein, human; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; D012319:RNA Polymerase II