DrosophilaStem-Loop Binding Protein Intracellular Localization Is Mediated by Phosphorylation and Is Required for Cell Cycle-regulated Histone mRNA Expression
Open Access
- 1 March 2004
- journal article
- Published by American Society for Cell Biology (ASCB) in Molecular Biology of the Cell
- Vol. 15 (3) , 1112-1123
- https://doi.org/10.1091/mbc.e03-09-0649
Abstract
Stem-loop binding protein (SLBP) is an essential component of the histone pre-mRNA processing machinery. SLBP protein expression was examined during Drosophila development by using transgenes expressing hemagglutinin (HA) epitope-tagged proteins expressed from the endogenous Slbp promoter. Full-length HA-dSLBP complemented a Slbp null mutation, demonstrating that it was fully functional. dSLBP protein accumulates throughout the cell cycle, in contrast to the observed restriction of mammalian SLBP to S phase. dSLBP is located in both nucleus and cytoplasm in replicating cells, but it becomes predominantly nuclear during G2. dSLBP is present in mitotic cells and is down-regulated in G1 when cells exit the cell cycle. We determined whether mutation at previously identified phosphorylation sites, T120 and T230, affected the ability of the protein to restore viability and histone mRNA processing to dSLBP null mutants. The T120A SLBP restored viability and histone pre-mRNA processing. However, the T230A mutant, located in a conserved TPNK sequence in the RNA binding domain, did not restore viability and histone mRNA processing in vivo, although it had full activity in histone mRNA processing in vitro. The T230A protein is concentrated in the cytoplasm, suggesting that it is defective in nuclear targeting, and accounting for its failure to function in histone pre-mRNA processing in vivo.Keywords
This publication has 34 references indexed in Scilit:
- A 3′ Exonuclease that Specifically Interacts with the 3′ End of Histone mRNAMolecular Cell, 2003
- Phosphorylation of Stem-Loop Binding Protein (SLBP) on Two Threonines Triggers Degradation of SLBP, the Sole Cell Cycle-Regulated Factor Required for Regulation of Histone mRNA Processing, at the End of S PhaseMolecular and Cellular Biology, 2003
- The Stem-Loop Binding Protein Is Required for Efficient Translation of Histone mRNA In Vivo and In VitroMolecular and Cellular Biology, 2002
- Developmental Control of Histone mRNA and dSLBP Synthesis duringDrosophilaEmbryogenesis and the Role of dSLBP in Histone mRNA 3′ End Processing In VivoMolecular and Cellular Biology, 2002
- A novel zinc finger protein is associated with U7 snRNP and interacts with the stem–loop binding protein in the histone pre-mRNP to stimulate 3′-end processingGenes & Development, 2002
- Mutations in the RNA Binding Domain of Stem-Loop Binding Protein Define Separable Requirements for RNA Binding and for Histone Pre-mRNA ProcessingMolecular and Cellular Biology, 2001
- Combinatorial Control of Cyclin B1 Nuclear Trafficking through Phosphorylation at Multiple SitesJournal of Biological Chemistry, 2001
- Formation of the 3′ end of histone mRNAGene, 1999
- Efficient Extraction and Partial Purification of the Polyribosome-Associated Stem−Loop Binding Protein Bound to the 3‘ End of Histone mRNABiochemistry, 1996
- Mitotic domains reveal early commitment of cells in Drosophila embryosTrends in Genetics, 1989