title: The kinase ABL phosphorylates the microprocessor subunit DGCR8 to stimulate primary microRNA processing in response to DNA damage.
abstract: The DNA damage response network stimulates microRNA (miRNA) biogenesis to coordinate repair, cell cycle checkpoints, and apoptosis. The multistep process of miRNA biogenesis involves the cleavage of primary miRNAs by the microprocessor complex composed of the ribonuclease Drosha and the RNA binding protein DGCR8. We found that the tyrosine kinase ABL phosphorylated DGCR8, a modification that was required for the induction of a subset of miRNAs after DNA damage. Focusing on the miR-34 family, ABL stimulated the production of miR-34c, but not miR-34a, through Drosha/DGCR8-dependent processing of primary miR-34c (pri-miR-34c). This miRNA-selective effect of ABL required the sequences flanking the precursor miR-34c (pre-miR-34c) stem-loop. In pri-miRNA processing, DGCR8 binds the pre-miR stem-loop and recruits Drosha to the miRNA. RNA cross-linking assays showed that DGCR8 and Drosha interacted with pri-miR-34c, but we found an inverse correlation between ABL-stimulated processing and DGCR8 association with pri-miR-34c. When coexpressed in HEK293T cells, ABL phosphorylated DGCR8 at Tyr(267). Ectopic expression of a Y267F-DGCR8 mutant reduced the recruitment of Drosha to pri-miR-34c and prevented ABL or Drosha from stimulating the processing of pri-miR-34c. In mice engineered to express a nuclear import-defective mutant of ABL, miR-34c, but not miR-34a, expression was reduced in the kidney, and apoptosis of the renal epithelial cells was impaired in response to cisplatin. These results reveal a new pathway in the DNA damage response wherein ABL-dependent tyrosine phosphorylation of DGCR8 stimulates the processing of selective primary miRNAs.
authors.affiliation: Moores Cancer Center and Division of Hematology-Oncology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0644, USA. Institute of Biomedical Sciences, Academia Sinica, Taipei 11529 Taiwan.
authors.forename: Chi-Chiang
authors.initials: CC
authors.lastname: Tu
authors.affiliation: Moores Cancer Center and Division of Hematology-Oncology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0644, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhong
authors.affiliation: Moores Cancer Center and Division of Hematology-Oncology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0644, USA.
authors.forename: Louis
authors.initials: L
authors.lastname: Nguyen
authors.affiliation: Moores Cancer Center and Division of Hematology-Oncology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0644, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Tsai
authors.affiliation: Moores Cancer Center and Division of Hematology-Oncology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0644, USA.
authors.forename: Priya
authors.initials: P
authors.lastname: Sridevi
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei 11529 Taiwan.
authors.forename: Woan-Yuh
authors.initials: WY
authors.lastname: Tarn
authors.affiliation: Moores Cancer Center and Division of Hematology-Oncology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0644, USA. jywang@ucsd.edu.
authors.forename: Jean Y J
authors.initials: JY
authors.lastname: Wang
mesh_terms: D000818:Animals; D004249:DNA Damage; D006801:Humans; D051379:Mice; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D016374:Oncogene Proteins v-abl / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000502:physiology; D012323:RNA Processing, Post-Transcriptional / Q000502:physiology*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C474043:DGCR8 protein, human; C474044:Dgcr8 protein, mouse; C522425:MIRN34 microRNA, human; C551848:MIRN34a microRNA, mouse; D035683:MicroRNAs; D016374:Oncogene Proteins v-abl; D016601:RNA-Binding Proteins