title: The Drosophila Helicase MLE Targets Hairpin Structures in Genomic Transcripts.
abstract: RNA hairpins are a common type of secondary structures that play a role in every aspect of RNA biochemistry including RNA editing, mRNA stability, localization and translation of transcripts, and in the activation of the RNA interference (RNAi) and microRNA (miRNA) pathways. Participation in these functions often requires restructuring the RNA molecules by the association of single-strand (ss) RNA-binding proteins or by the action of helicases. The Drosophila MLE helicase has long been identified as a member of the MSL complex responsible for dosage compensation. The complex includes one of two long non-coding RNAs and MLE was shown to remodel the roX RNA hairpin structures in order to initiate assembly of the complex. Here we report that this function of MLE may apply to the hairpins present in the primary RNA transcripts that generate the small molecules responsible for RNA interference. Using stocks from the Transgenic RNAi Project and the Vienna Drosophila Research Center, we show that MLE specifically targets hairpin RNAs at their site of transcription. The association of MLE at these sites is independent of sequence and chromosome location. We use two functional assays to test the biological relevance of this association and determine that MLE participates in the RNAi pathway.
authors.affiliation: Department of Biology, Emory University, Atlanta, Georgia, United States of America.
authors.forename: Simona
authors.initials: S
authors.lastname: Cugusi
authors.affiliation: Department of Human Genetics, Emory University School of Medicine, Atlanta.
authors.forename: Yujing
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Human Genetics, Emory University School of Medicine, Atlanta.
authors.forename: Peng
authors.initials: P
authors.lastname: Jin
authors.affiliation: Department of Biology, Emory University, Atlanta, Georgia, United States of America.
authors.forename: John C
authors.initials: JC
authors.lastname: Lucchesi
mesh_terms: D000818:Animals; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics*; D004265:DNA Helicases / Q000235:genetics*; D004303:Dosage Compensation, Genetic; D029721:Drosophila Proteins / Q000235:genetics*; D004331:Drosophila melanogaster; D035683:MicroRNAs / Q000235:genetics; D009690:Nucleic Acid Conformation; D017393:RNA Editing; D034622:RNA Interference; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D029721:Drosophila Proteins; D035683:MicroRNAs; D014157:Transcription Factors; C070837:mle protein, Drosophila; D004265:DNA Helicases