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Ubiquitin-like protein Hub1 is required for pre-mRNA splicing and localization of an essential splicing factor in fission yeast

Item Type:Article
Title:Ubiquitin-like protein Hub1 is required for pre-mRNA splicing and localization of an essential splicing factor in fission yeast
Creators Name:Wilkinson, C.R. and Dittmar, G.A. and Ohi, M.D. and Uetz, P. and Jones, N. and Finley, D.
Abstract:Hub1/Ubl5 is a member of the family of ubiquitin-like proteins (UBLs). The tertiary structure of Hub1 is similar to that of ubiquitin; however, it differs from known modifiers in that there is no conserved glycine residue near the C terminus which, in ubiquitin and UBLs, is required for covalent modification of target proteins. Instead, there is a conserved dityrosine motif proximal to the terminal nonconserved amino acid. In S. cerevisiae, high molecular weight adducts can be formed in vivo from Hub1, but the structure of these adducts is not known, and they could be either covalent or noncovalent. The budding yeast HUB1 gene is not essential, but Delta hub1 mutants display defects in mating. Here, we report that fission yeast hub1 is an essential gene, whose loss results in cell cycle defects and inefficient pre-mRNA splicing. A screen for Hub1 interactors identified Snu66, a component of the U4/U6.U5 tri-snRNP splicing complex. Furthermore, overexpression of Snu66 suppresses the lethality of a hub1ts mutant. In cells lacking functional hub1, the nuclear localization of Snu66 is disrupted, suggesting that an important role for Hub1 is the correct subcellular targeting of Snu66, although our data suggest that Hub1 is likely to perform other roles in splicing as well.
Keywords:Cell Cycle, Essential Genes, Flow Cytometry, Fluorescence Microscopy, Mutation, Oligonucleotides, Polyacrylamide Gel Electrophoresis, Protein Transport, RNA Splicing, Reverse Transcriptase Polymerase Chain Reaction, Schizosaccharomyces, Schizosaccharomyces pombe Proteins, Small Nuclear Ribonucleoproteins, Two-Hybrid System Techniques, Ubiquitin-Protein Ligase Complexes
Source:Current Biology
Publisher:Cell Press
Page Range:2283-2288
Date:29 December 2004
Official Publication:https://doi.org/10.1016/j.cub.2004.11.058
PubMed:View item in PubMed

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