Open AccessStructural basis for 5'-ETS recognition by Utp4 at the early stages of ribosome biogenesis
Author(s) -
Fabiola R. Calviño,
Markus Kornprobst,
Géza Schermann,
Fabienne Birkle,
Klemens Wild,
Tamás Fischer,
Ed Hurt,
Yasar Luqman Ahmed,
Irmgard Sinning
Publication year - 2017
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0178752
Subject(s) - ribosome biogenesis , ribosome , rna , biology , ribosomal rna , microbiology and biotechnology , computational biology , eukaryotic ribosome , biogenesis , 5.8s ribosomal rna , context (archaeology) , rna induced transcriptional silencing , ribosomal protein , genetics , non coding rna , gene , paleontology
Eukaryotic ribosome biogenesis begins with the co-transcriptional assembly of the 90S pre-ribosome. The ‘U three protein’ (UTP) complexes and snoRNP particles arrange around the nascent pre-ribosomal RNA chaperoning its folding and further maturation. The earliest event in this hierarchical process is the binding of the UTP-A complex to the 5'-end of the pre-ribosomal RNA (5'-ETS). This oligomeric complex predominantly consists of β-propeller and α-solenoidal proteins. Here we present the structure of the Utp4 subunit from the thermophilic fungus Chaetomium thermophilum at 2.15 Å resolution and analyze its function by UV RNA-crosslinking (CRAC) and in context of a recent cryo-EM structure of the 90S pre-ribosome. Utp4 consists of two orthogonal and highly basic β-propellers that perfectly fit the EM-data. The Utp4 structure highlights an unusual Velcro-closure of its C-terminal β-propeller as relevant for protein integrity and potentially Utp8 recognition in the context of the pre-ribosome. We provide a first model of the 5'-ETS RNA from the internally hidden 5'-end up to the region that hybridizes to the 3'-hinge sequence of U3 snoRNA and validate a specific Utp4/5'-ETS interaction by CRAC analysis.