The spliceosomal snRNP core complex ofTrypanosoma brucei: Cloning and functional analysis reveals seven Sm protein constituents
Open Access
- 18 July 2000
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 97 (16) , 8967-8972
- https://doi.org/10.1073/pnas.150236097
Abstract
Each of the trypanosome small nuclear ribonucleoproteins (snRNPs) U2, U4/U6, and U5, as well as the spliced leader (SL) RNP, contains a core of common proteins, which we have previously identified. This core is unusual because it is not recognized by anti-Sm Abs and it associates with an Sm-related sequence in the trypanosome small nuclear RNAs (snRNAs). Using peptide sequences derived from affinity-purified U2 snRNP proteins, we have cloned cDNAs for five common proteins of 8.5, 10, 12.5, 14, and 15 kDa of Trypanosoma brucei and identified them as Sm proteins SmF (8.5 kDa), -E (10 kDa), -D1 (12.5 kDa), -G (14 kDa), and -D2 (15 kDa), respectively. Furthermore, we found the trypanosome SmB (T. brucei) and SmD3 (Trypanosoma cruzi) homologues through database searches, thus completing a set of seven canonical Sm proteins. Sequence comparisons of the trypanosome proteins revealed several deviations in highly conserved positions from the Sm consensus motif. We have identified a network of specific heterodimeric and -trimeric Sm protein interactions in vitro. These results are summarized in a model of the trypanosome Sm core, which argues for a strong conservation of the Sm particle structure. The conservation extends also to the functional level, because at least one trypanosome Sm protein, SmG, was able to specifically complement a corresponding mutation in yeast.Keywords
This publication has 43 references indexed in Scilit:
- The C-terminal RG Dipeptide Repeats of the Spliceosomal Sm Proteins D1 and D3 Contain Symmetrical Dimethylarginines, Which Form a Major B-cell Epitope for Anti-Sm AutoantibodiesJournal of Biological Chemistry, 2000
- Cloning and mutational analysis of the Leptomonas seymouri U5 snRNA gene: function of the Sm site in core RNP formation and nuclear localizationNucleic Acids Research, 1999
- Identification of the proteins of the yeast U1 small nuclear ribonucleoprotein complex by mass spectrometryProceedings of the National Academy of Sciences, 1997
- Electron microscopy of assembly intermediates of the snRNP core: morphological similarities between the RNA-free (E.F.G) protein heteromer and the intact snRNP coreJournal of Molecular Biology, 1997
- The yeast SME1 gene encodes the homologue of the human E core proteinGene, 1996
- [1] Getting started with yeastPublished by Elsevier ,1991
- Destruction of U2, U4, or U6 small nuclear RNA blocks Trans splicing in trypanosome cellsCell, 1990
- Electron microscopy of small nuclear ribonucleoprotein (snRNP) particles U2 and U5: evidence for a common structure-determining principle in the major U snRNP family.Proceedings of the National Academy of Sciences, 1990
- Tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis for the separation of proteins in the range from 1 to 100 kDaAnalytical Biochemistry, 1987
- Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications.Proceedings of the National Academy of Sciences, 1979