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Protein localisation by electron microscopy reveals the architecture of the yeast spliceosomal B complex
Author(s) -
Rigo Norbert,
Sun Chengfu,
Fabrizio Patrizia,
Kastner Berthold,
Lührmann Reinhard
Publication year - 2015
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 - 10.15252/embj.201592022
Subject(s) - planck , chemistry , biophysics , library science , physics , biology , computer science , quantum mechanics
The spliceosome assembles on a pre‐ mRNA intron by binding of five sn RNP s and numerous proteins, leading to the formation of the pre‐catalytic B complex. While the general morphology of the B complex is known, the spatial arrangement of proteins and sn RNP subunits within it remain to be elucidated. To shed light on the architecture of the yeast B complex, we immuno‐labelled selected proteins and located them by negative‐stain electron microscopy. The B complex exhibited a triangular shape with main body, head and neck domains. We located the U5 sn RNP components Brr2 at the top and Prp8 and Snu114 in the centre of the main body. We found several U2 SF 3a (Prp9 and Prp11) and SF 3b (Hsh155 and Cus1) proteins in the head domain and two U4/U6 sn RNP proteins (Prp3 and Lsm4) in the neck domain that connects the main body with the head. Thus, we could assign distinct domains of the B complex to the respective sn RNP s and provide the first detailed picture of the subunit architecture and protein arrangements of the B complex.