Purified U7 snRNPs lack the Sm proteins D1 and D2 but contain Lsm10, a new 14 kDa Sm D1-like protein

Pillai, Ramesh S.; Will, Cindy L.; Lührmann, Reinhard; Schümperli, Daniel; Müller, Berndt

doi:10.1093/emboj/20.19.5470

Cited by 143 publications

(169 citation statements)

References 47 publications

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“…U7 snRNPs are strongly associated with CBs (Frey and Matera 1995;Pillai et al 2001), and although U1 snRNPs do not accumulate prominently in CBs at steady state, they likely transit through them (Sleeman and Lamond 1999).…”

Section: Discussionmentioning

confidence: 99%

“…Since Bellini and Gall (1998) showed that coilin interacts weakly with the U7 snRNP, we also decided to test if Lsm10, a U7-specific Sm protein that does not contain RG repeats ( Fig. 1; Pillai et al 2001), would bind to coilin. Lsm10 was translated in vitro and tested for interaction with either GST-C214 or GST alone.…”

Section: Coilin Binds To the Sm-fold Regions Of Sm And Sm-like Proteinsmentioning

confidence: 99%

“…Assembly of the U7 snRNP is mediated by a specialized SMN complex that also lacks Sm D1 and D2, but contains Lsm10 and Lsm11 instead (Pillai et al 2003). Otherwise, assembly and nuclear import of U7 snRNPs resembles the pathway for spliceosomal snRNPs (Stefanovic et al 1995), and U7 snRNPs are predominantly localized to CBs with low levels being present in the nucleoplasm (Frey and Matera 1995;Pillai et al 2001). Thus, both the spliceosomal U snRNPs and the U7 snRNP, along with many, but not all, of the snRNP-specific proteins are highly enriched within CBs.…”

Section: Introductionmentioning

confidence: 99%

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The C-terminal domain of coilin interacts with Sm proteins and U snRNPs

Pillai

Azzouz

et al. 2005

Chromosoma

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Coilin is the signature protein of the Cajal body (CB), a nuclear suborganelle involved in the biogenesis of small nuclear ribonucleoproteins (snRNPs). Newly imported Sm-class snRNPs are thought to traffic through CBs before proceeding to their final nuclear destinations. Loss of coilin function in mice leads to significant viability and fertility problems. Coilin interacts directly with the spinal muscular atrophy (SMA) protein via dimethylarginine residues in its C-terminal domain. Although coilin hypomethylation results in delocalization of survival of motor neurons (SMN) from CBs, high concentrations of snRNPs remain within these structures. Thus, CBs appear to be involved in snRNP maturation, but factors that tether snRNPs to CBs have not been described. In this report, we demonstrate that the coilin C-terminal domain binds directly to various Sm and Lsm proteins via their Sm motifs. We show that the region of coilin responsible for this binding activity is separable from that which binds to SMN. Interestingly, U2, U4, U5, and U6 snRNPs interact with the coilin C-terminal domain in a glutathione S-transferase (GST)-pulldown assay, whereas U1 and U7 snRNPs do not. Thus, the ability to interact with free Sm (and Lsm) proteins as well as with intact snRNPs, indicates that coilin and CBs may facilitate the modification of newly formed snRNPs, the regeneration of 'mature' snRNPs, or the reclamation of unassembled snRNP components.

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Section: Discussionmentioning

confidence: 99%

Section: Coilin Binds To the Sm-fold Regions Of Sm And Sm-like Proteinsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The C-terminal domain of coilin interacts with Sm proteins and U snRNPs

Pillai

Azzouz

et al. 2005

Chromosoma

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“…Total RNAs were isolated from immunoprecipitates obtained with different antibodies (anti-dLsm11, Y12, or anti-HA) from 1 mL samples of S2 wild-type nuclear extract (large scale; Dignam et al 1983;Pillai et al 2001) or from 400 µL of nuclear extract from the S2 cell line stably expressing HA-dLsm11 (small scale; Pillai et al 2001). The RNAs were extracted at 65°C with a buffer containing 10 mM Tris-HCl (pH 8), 5 mM EDTA, 0.5% SDS, 1 mg proteinase K, and 4 µg glycogen.…”

Section: Extract Preparation and Protein Interaction Studiesmentioning

confidence: 99%

Evolutionary conservation of the U7 small nuclear ribonucleoprotein inDrosophila melanogaster

Azzouz

Schümperli²

2003

RNA

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The U7 snRNP involved in histone RNA 3 end processing is related to but biochemically distinct from spliceosomal snRNPs. In vertebrates, the Sm core structure assembling around the noncanonical Sm-binding sequence of U7 snRNA contains only five of the seven standard Sm proteins. The missing Sm D1 and D2 subunits are replaced by U7-specific Sm-like proteins Lsm10 and Lsm11, at least the latter of which is important for histone RNA processing. So far, it was unknown if this special U7 snRNP composition is conserved in invertebrates. Here we describe several putative invertebrate Lsm10 and Lsm11 orthologs that display low but clear sequence similarity to their vertebrate counterparts. Immunoprecipitation studies in Drosophila S2 cells indicate that the Drosophila Lsm10 and Lsm11 orthologs (dLsm10 and dLsm11) associate with each other and with Sm B, but not with Sm D1 and D2. Moreover, dLsm11 associates with the recently characterized Drosophila U7 snRNA and, indirectly, with histone H3 pre-mRNA. Furthermore, dLsm10 and dLsm11 can assemble into U7 snRNPs in mammalian cells. These experiments demonstrate a strong evolutionary conservation of the unique U7 snRNP composition, despite a high degree of primary sequence divergence of its constituents. Therefore, Drosophila appears to be a suitable system for further genetic studies of the cell biology of U7 snRNPs.

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“…The Lsm2p-8p complex was also shown to bind U8 snoRNA in Xenopus (14), and yeast U7 snoRNA binds to Lsm proteins (15), suggesting that Lsm proteins may play a role in the stabilization of other small stable RNAs. In yeast, Lsm proteins were shown to be required for pre-tRNA and pre-rRNA processing (10,16).…”

mentioning

confidence: 99%

Identification and Functional Characterization of Lsm Proteins in Trypanosoma brucei

Liu¹,

Liang²,

Uliel

et al. 2004

Journal of Biological Chemistry

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RNA interference of Sm proteins inTrypanosoma brucei demonstrated that the stability of the small nuclear RNAs (U1, U2, U4, U5) and the spliced leader RNA, but not U6 RNA, were affected upon Sm depletion (Mandelboim, M., Barth, S., Biton, M., Liang, X. H., and Michaeli, S. (2003) J. Biol. Chem. 278, 51469-51478), suggesting that Lsm proteins that bind and stabilize U6 RNA in other eukaryotes should exist in trypanosomes. In this study, we identified seven Lsm proteins (Lsm2p to Lsm8p) and examined the function of Lsm3p and Lsm8p by RNA interference silencing. Both Lsm proteins were found to be essential for U6 stability and mRNA decay. Silencing was lethal, and cisand trans-splicing were inhibited. Importantly, silencing also affected the level of U4.U6 and the U4.U6/U5 tri-small nuclear ribonucleoprotein complexes. The presence of Lsm proteins in trypanosomes that diverged early in the eukaryotic lineage suggests that these proteins are highly conserved in both structure and function among eukaryotes. Interestingly, however, Lsm1p that is specific to the mRNA decay complex was not identified in the genome data base of any kinetoplastidae, and the Lsm8p that in other eukaryotes exclusively functions in U6 stability was found to function in trypanosomes also in mRNA decay. These data therefore suggest that in trypanosomes only a single Lsm complex may exist.

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Purified U7 snRNPs lack the Sm proteins D1 and D2 but contain Lsm10, a new 14 kDa Sm D1-like protein

Cited by 143 publications

References 47 publications

The C-terminal domain of coilin interacts with Sm proteins and U snRNPs

The C-terminal domain of coilin interacts with Sm proteins and U snRNPs

Evolutionary conservation of the U7 small nuclear ribonucleoprotein inDrosophila melanogaster

Identification and Functional Characterization of Lsm Proteins in Trypanosoma brucei

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