title: RNA helicase p68 (DDX5) regulates tau exon 10 splicing by modulating a stem-loop structure at the 5' splice site.
abstract: Regulation of tau exon 10 splicing plays an important role in tauopathy. One of the cis elements regulating tau alternative splicing is a stem-loop structure at the 5' splice site of tau exon 10. The RNA helicase(s) modulating this stem-loop structure was unknown. We searched for splicing regulators interacting with this stem-loop region using an RNA affinity pulldown-coupled mass spectrometry approach and identified DDX5/RNA helicase p68 as an activator of tau exon 10 splicing. The activity of p68 in stimulating tau exon 10 inclusion is dependent on RBM4, an intronic splicing activator. RNase H cleavage and U1 protection assays suggest that p68 promotes conformational change of the stem-loop structure, thereby increasing the access of U1snRNP to the 5' splice site of tau exon 10. This study reports the first RNA helicase interacting with a stem-loop structure at the splice site and regulating alternative splicing in a helicase-dependent manner. Our work uncovers a previously unknown function of p68 in regulating tau exon 10 splicing. Furthermore, our experiments reveal functional interaction between two splicing activators for tau exon 10, p68 binding at the stem-loop region and RBM4 interacting with the intronic splicing enhancer region.
authors.affiliation: Northwestern University Feinberg School of Medicine, 303 E. Superior St., Lurie 6-117, Chicago, IL 60611, USA.
authors.forename: Amar
authors.initials: A
authors.lastname: Kar
authors.forename: Kazuo
authors.initials: K
authors.lastname: Fushimi
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Zhou
authors.forename: Payal
authors.initials: P
authors.lastname: Ray
authors.forename: Chen
authors.initials: C
authors.lastname: Shi
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Chen
authors.forename: Zhiren
authors.initials: Z
authors.lastname: Liu
authors.forename: She
authors.initials: S
authors.lastname: Chen
authors.forename: Jane Y
authors.initials: JY
authors.lastname: Wu
mesh_terms: D002460:Cell Line; D053487:DEAD-box RNA Helicases / Q000378:metabolism*; D005091:Exons; D006801:Humans; D009690:Nucleic Acid Conformation; D012326:RNA Splicing; D016601:RNA-Binding Proteins / Q000378:metabolism; D017411:Ribonucleoproteins, Small Nuclear / Q000378:metabolism; D016875:tau Proteins / Q000235:genetics*
chemical_list: C473692:RBM4 protein, human; D016601:RNA-Binding Proteins; D017411:Ribonucleoproteins, Small Nuclear; C552127:SNRNP35 protein, human; D016875:tau Proteins; C506749:Ddx5 protein, human; D053487:DEAD-box RNA Helicases