title: The DEAD-box protein Dbp2 functions with the RNA-binding protein Yra1 to promote mRNP assembly.
abstract: Eukaryotic gene expression involves numerous biochemical steps that are dependent on RNA structure and ribonucleoprotein (RNP) complex formation. The DEAD-box class of RNA helicases plays fundamental roles in formation of RNA and RNP structure in every aspect of RNA metabolism. In an effort to explore the diversity of biological roles for DEAD-box proteins, our laboratory recently demonstrated that the DEAD-box protein Dbp2 associates with actively transcribing genes and is required for normal gene expression in Saccharomyces cerevisiae. We now provide evidence that Dbp2 interacts genetically and physically with the mRNA export factor Yra1. In addition, we find that Dbp2 is required for in vivo assembly of mRNA-binding proteins Yra1, Nab2, and Mex67 onto poly(A)+ RNA. Strikingly, we also show that Dbp2 is an efficient RNA helicase in vitro and that Yra1 decreases the efficiency of ATP-dependent duplex unwinding. We provide a model whereby messenger ribonucleoprotein (mRNP) assembly requires Dbp2 unwinding activity and once the mRNP is properly assembled, inhibition by Yra1 prevents further rearrangements. Both Yra1 and Dbp2 are conserved in multicellular eukaryotes, suggesting that this constitutes a broadly conserved mechanism for stepwise assembly of mature mRNPs in the nucleus.
authors.affiliation: Department of Biochemistry, Purdue University, BCHM 305, 175 South University Street, West Lafayette, IN 47907-2063, USA; Purdue University Center for Cancer Research, Purdue University, Hansen Life Sciences Research Building, Room 141, 201 South University Street, West Lafayette, IN 47907-2064, USA.
authors.forename: Wai Kit
authors.initials: WK
authors.lastname: Ma
authors.forename: Sara C
authors.initials: SC
authors.lastname: Cloutier
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Tran
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D002384:Catalysis; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000378:metabolism*; D004843:Epistasis, Genetic; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D029543:Nucleocytoplasmic Transport Proteins / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D012331:RNA, Fungal / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C106898:MEX67 protein, S cerevisiae; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; C105887:YRA1 protein, S cerevisiae; C026452:messenger ribonucleoprotein; D000255:Adenosine Triphosphate; C438898:Dbp2 protein, S cerevisiae; D053487:DEAD-box RNA Helicases
keywords: BSA; EDTA; GST; REF; RNA annealing; RNA export factor; RNA recognition motif; RNA unwinding; RRM; RT-qPCR; TAP; TEV; bovine serum albumin; co-transcriptional; double-stranded RNA; dsRNA; ethylenediaminetetraacetic acid; gene expression; glutathione S-transferase; mRNP; mRNP remodeling; messenger ribonucleoprotein; pre-mRNA; precursor messenger RNA; reverse transcription-quantitative PCR; tandem affinity purification; tobacco etch virus