Composition of yeast snRNPs and snoRNPs in the absence of trimethylguanosine caps reveals nuclear cap binding protein as a gained U1 component implicated in the cold-sensitivity of tgs1δ cells Journal Article
| Authors: | Schwer, B.; Erdjument-Bromage, H.; Shuman, S. |
| Article Title: | Composition of yeast snRNPs and snoRNPs in the absence of trimethylguanosine caps reveals nuclear cap binding protein as a gained U1 component implicated in the cold-sensitivity of tgs1δ cells |
| Abstract: | Small nuclear and nucleolar RNAs that program pre-mRNA splicing and rRNA processing have a signature 50-trimethylguanosine (TMG) cap. Whereas the mechanism of TMG synthesis by Tgs1 methyltransferase has been elucidated, we know little about whether or how RNP biogenesis, structure and function are perturbed when TMG caps are missing. Here, we analyzed RNPs isolated by tandem-affinity purification from TGS1 and tgs1" yeast strains. The protein and U-RNA contents of total SmB-containing RNPs were similar. Finer analysis revealed stoichiometric association of the nuclear cap-binding protein (CBP) subunits Sto1 and Cbc2 with otherwise intact Mud1- and Nam8- containing U1 snRNPs from tgs1" cells. CBP was not comparably enriched in Lea1-containing U2 snRNPs from tgs1" cells. Moreover, CBP was not associated with mature Nop58-containing C/D snoRNPs or mature Cbf5- and Gar1-containing H/ACA snoRNPs from tgs1δ cells. The protein composition and association of C/D snoRNPs with the small subunit (SSU) processosome were not grossly affected by absence of TMG caps, nor was the composition of H/ACA snoRNPs. The cold-sensitive (cs) growth defect of tgs1" yeast cells could be suppressed by mutating the cap-binding pocket of Cbc2, suggesting that ectopic CBP binding to the exposed U1 m 7G cap in tgs1δ cells (not lack of TMG caps per se) underlies the cs phenotype. © 2011 The Author(s). |
| Keywords: | controlled study; unclassified drug; nonhuman; protein analysis; phenotype; protein binding; guanosine derivative; protein purification; saccharomyces cerevisiae; protein subunit; small nuclear ribonucleoprotein; yeast cell; fungal protein; fungus growth; stoichiometry; protein isolation; cold sensitivity; fungal rna; dyskerin; fungal metabolism; protein content; small nucleolar ribonucleoprotein; nuclear cap binding protein; processosome; protein gar1; protein mud1; protein nam8; protein nop58; small nucleolar ribonucleoprotein cbc2 subunit; small nucleolar ribonucleoprotein sto1 subunit; trimethylguanosine; fungus mutation; tandem affinity purification |
| Journal Title: | Nucleic Acids Research |
| Volume: | 39 |
| Issue: | 15 |
| ISSN: | 0305-1048 |
| Publisher: | Oxford University Press |
| Date Published: | 2011-08-01 |
| Start Page: | 6715 |
| End Page: | 6728 |
| Language: | English |
| DOI: | 10.1093/nar/gkr279 |
| PROVIDER: | scopus |
| PMCID: | PMC3159458 |
| PUBMED: | 21558325 |
| DOI/URL: | |
| Notes: | --- - "Cited By (since 1996): 3" - "Export Date: 21 June 2012" - "CODEN: NARHA" - "Source: Scopus" |
