Recruitment, Duplex Unwinding and Protein-Mediated Inhibition of the Dead-Box RNA Helicase Dbp2 at Actively Transcribed Chromatin

JOURNAL OF MOLECULAR BIOLOGY

卷:428

Article

Ma, Wai Kit¹  Paudel, Bishnu P.^2,3  Xing, Zheng¹  Sabath, Ivan G.¹  Rueda, David^2,3  Tran, Elizabeth J.^1,4 

[1] Purdue Univ, Dept Biochem, BCHM 305,175 S Univ St, W Lafayette, IN 47907 USA

[2] Univ London Imperial Coll Sci Technol & Med, Dept Med, Virol Sect, Du Cane Rd, London W12 0NN, England

[3] Univ London Imperial Coll Sci Technol & Med, Single Mol Imaging Grp, MRC Clin Sci Ctr, Du Cane Rd, London W12 0NN, England

[4] Purdue Univ, Ctr Canc Res, Hansen Life Sci Res Bldg,Room 141,201 S Univ St, W Lafayette, IN 47907 USA

关键词: DEAD-box;    helicase;    RNA-protein complex;    chromatin;    RNA;   

DOI  :  10.1016/j.jmb.2016.02.005

来源: Elsevier

【 摘 要 】

RNA helicases play fundamental roles in modulating RNA structures and facilitating RNA protein (RNP) complex assembly in vivo. Previously, our laboratory demonstrated that the DEAD-box RNA helicase Dbp2 in Saccharomyces cerevisiae is required to promote efficient assembly of the co-transcriptionally associated mRNA-binding proteins Yra1, Nab2, and Mex67 onto poly(A)(+) RNA. We also found that Yra1 associates directly with Dbp2 and functions as an inhibitor of Dbp2-dependent duplex unwinding, suggestive of a cycle of unwinding and inhibition by Dbp2. To test this, we undertook a series of experiments to shed light on the order of events for Dbp2 in co-transcriptional mRNP assembly. We now show that Dbp2 is recruited to chromatin via RNA and forms a large, RNA-dependent complex with Yra1 and Mex67. Moreover, single-molecule fluorescence resonance energy transfer and bulk biochemical assays show that Yra1 inhibits unwinding in a concentration-dependent manner by preventing the association of Dbp2 with single-stranded RNA. This inhibition prevents over-accumulation of Dbp2 on mRNA and stabilization of a subset of RNA polymerase II transcripts. We propose a model whereby Yra1 terminates a cycle of mRNP assembly by Dbp2. (C) 2016 Elsevier Ltd. All rights reserved.

【 授权许可】

Free