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Structure and function of an RNase H domain at the heart of the spliceosome
Author(s) -
Pena Vladimir,
Rozov Alexey,
Fabrizio Patrizia,
Lührmann Reinhard,
Wahl Markus C
Publication year - 2008
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/emboj.2008.209
Subject(s) - rna splicing , spliceosome , biology , rnase p , rnase h , genetics , rnase ph , rna , rnase mrp , gene
Precursor‐messenger RNA (pre‐mRNA) splicing encompasses two sequential transesterification reactions in distinct active sites of the spliceosome that are transiently established by the interplay of small nuclear (sn) RNAs and spliceosomal proteins. Protein Prp8 is an active site component but the molecular mechanisms, by which it might facilitate splicing catalysis, are unknown. We have determined crystal structures of corresponding portions of yeast and human Prp8 that interact with functional regions of the pre‐mRNA, revealing a phylogenetically conserved RNase H fold, augmented by Prp8‐specific elements. Comparisons to RNase H–substrate complexes suggested how an RNA encompassing a 5′‐splice site (SS) could bind relative to Prp8 residues, which on mutation, suppress splice defects in pre‐mRNAs and snRNAs. A truncated RNase H‐like active centre lies next to a known contact region of the 5′SS and directed mutagenesis confirmed that this centre is a functional hotspot. These data suggest that Prp8 employs an RNase H domain to help assemble and stabilize the spliceosomal catalytic core, coordinate the activities of other splicing factors and possibly participate in chemical catalysis of splicing.