Architecture and nucleic acids recognition mechanism of the THO complex, an mRNP assembly factor.
The THO complex is a key factor in co-transcriptional formation of export-competent messenger ribonucleoprotein particles, yet its structure and mechanism of chromatin recruitment remain unknown. In yeast, this complex has been described as a heterotetramer (Tho2, Hpr1, Mft1, and Thp2) that interacts with Tex1 and mRNA export factors Sub2 and Yra1 to form the TRanscription EXport (TREX) complex. In this study, we purified yeast THO and found Tex1 to be part of its core. We determined the three-dimensional structures of five-subunit THO complex by electron microscopy and located the positions of Tex1, Hpr1, and Tho2 C-terminus using various labelling techniques. In the case of Tex1, a β-propeller protein, we have generated an atomic model which docks into the corresponding part of the THO complex envelope. Furthermore, we show that THO directly interacts with nucleic acids through the unfolded C-terminal region of Tho2, whose removal reduces THO recruitment to active chromatin leading to mRNA biogenesis defects. In summary, this study describes the THO architecture, the structural basis for its chromatin targeting, and highlights the importance of unfolded regions of eukaryotic proteins.
Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain.
Alvaro
A
Peña
Kamil
K
Gewartowski
Seweryn
S
Mroczek
Jorge
J
Cuéllar
Aleksandra
A
Szykowska
Andrzej
A
Prokop
Mariusz
M
Czarnocki-Cieciura
Jan
J
Piwowarski
Cristina
C
Tous
Andrés
A
Aguilera
José L
JL
Carrascosa
José María
JM
Valpuesta
Andrzej
A
Dziembowski
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D009696:Nucleic Acids / Q000378:metabolism*; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D012261:Ribonucleoproteins / Q000235:genetics* / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics
D002843:Chromatin; D004268:DNA-Binding Proteins; C063494:HPR1 protein, S cerevisiae; D009687:Nuclear Proteins; D009696:Nucleic Acids; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; C405934:THO2 protein, S cerevisiae; C462947:Thp2 protein, S cerevisiae; D014157:Transcription Factors; C105887:YRA1 protein, S cerevisiae; C026452:messenger ribonucleoprotein; C068359:MFT1 protein, S cerevisiae; D000251:Adenosine Triphosphatases; C027900:RNA-dependent ATPase