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Updated: Jun 22, 2026

Isolation of F1-ATPase from the Parasitic Protist Trypanosoma brucei
Published on: January 22, 2019
Special Sm core complex functions in assembly of the U2 small nuclear ribonucleoprotein of Trypanosoma brucei
Christian Preusser1, Zsofia Palfi, Albrecht Bindereif
1Institute of Biochemistry, Justus Liebig University of Giessen, Germany.
Abstract:
The processing of polycistronic pre-mRNAs in trypanosomes requires the spliceosomal small ribonucleoprotein complexes (snRNPs) U1, U2, U4/U6, U5, and SL, each of which contains a core of seven Sm proteins. Recently we reported the first evidence for a core variation in spliceosomal snRNPs; specifically, in the trypanosome U2 snRNP, two of the canonical Sm proteins, SmB and SmD3, are replaced by two U2-specific Sm proteins, Sm15K and Sm16.5K. Here we identify the U2-specific, nuclear-localized U2B'' protein from Trypanosoma brucei. U2B'' interacts with a second U2 snRNP protein, U2-40K (U2A'), which in turn contacts the U2-specific Sm16.5K/15K subcomplex. Together they form a high-affinity, U2-specific binding complex. This trypanosome-specific assembly differs from the mammalian system and provides a functional role for the Sm core variation found in the trypanosomal U2 snRNP.
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