scholarly journals Stem-Loop Binding Protein, the Protein That Binds the 3′ End of Histone mRNA, Is Cell Cycle Regulated by Both Translational and Posttranslational Mechanisms

2000 ◽  
Vol 20 (12) ◽  
pp. 4188-4198 ◽  
Author(s):  
Michael L. Whitfield ◽  
Lian-Xing Zheng ◽  
Amy Baldwin ◽  
Tomohiko Ohta ◽  
Myra M. Hurt ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Regulation ◽  
Binding Protein ◽  
S Phase ◽  
Mrna Processing ◽  
Mrna Levels ◽  
Histone Mrna ◽  
Stem Loop ◽  
Histone Mrnas ◽  
Cycle Regulation

ABSTRACT The expression of the replication-dependent histone mRNAs is tightly regulated during the cell cycle. As cells progress from G1 to S phase, histone mRNA levels increase 35-fold, and they decrease again during G2 phase. Replication-dependent histone mRNAs are the only metazoan mRNAs that lack polyadenylated tails, ending instead in a conserved stem-loop. Much of the cell cycle regulation is posttranscriptional and is mediated by the 3′ stem-loop. A 31-kDa stem-loop binding protein (SLBP) binds the 3′ end of histone mRNA. The SLBP is necessary for pre-mRNA processing and accompanies the histone mRNA to the cytoplasm, where it is a component of the histone messenger RNP. We used synchronous CHO cells selected by mitotic shakeoff and HeLa cells synchronized at the G1/S or the M/G1 boundary to study the regulation of SLBP during the cell cycle. In each system the amount of SLBP is regulated during the cell cycle, increasing 10- to 20-fold in the late G1 and then decreasing in the S/G2border. SLBP mRNA levels are constant during the cell cycle. SLBP is regulated at the level of translation as cells progress from G1 to S phase, and the protein is rapidly degraded as they progress into G2. Regulation of SLBP may account for the posttranscriptional component of the cell cycle regulation of histone mRNA.

scholarly journals 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 Phase

2003 ◽  
Vol 23 (5) ◽  
pp. 1590-1601 ◽  
Author(s):  
Lianxing Zheng ◽  
Zbigniew Dominski ◽  
Xiao-Cui Yang ◽  
Phillip Elms ◽  
Christy S. Raska ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Amino Acids ◽  
Posttranscriptional Regulation ◽  
Binding Protein ◽  
S Phase ◽  
Mrna Processing ◽  
Histone Mrna ◽  
Stem Loop ◽  
Histone Mrnas ◽  
Nuclear Extracts

ABSTRACT The replication-dependent histone mRNAs, the only eukaryotic mRNAs that do not have poly(A) tails, are present only in S-phase cells. Coordinate posttranscriptional regulation of histone mRNAs is mediated by the stem-loop at the 3′ end of histone mRNAs. The protein that binds the 3′ end of histone mRNA, stem-loop binding protein (SLBP), is required for histone pre-mRNA processing and is involved in multiple aspects of histone mRNA metabolism. SLBP is also regulated during the cell cycle, accumulating as cells enter S phase and being rapidly degraded as cells exit S phase. Mutation of any residues in a TTP sequence (amino acids 60 to 62) or mutation of a consensus cyclin binding site (amino acids 99 to 104) stabilizes SLBP in G2 and mitosis. These two threonines are phosphorylated in late S phase, as determined by mass spectrometry (MS) of purified SLBP from late S-phase cells, triggering SLBP degradation. Cells that express a stable SLBP still degrade histone mRNA at the end of S phase, demonstrating that degradation of SLBP is not required for histone mRNA degradation. Nuclear extracts from G1 and G2 cells are deficient in histone pre-mRNA processing, which is restored by addition of recombinant SLBP, indicating that SLBP is the only cell cycle-regulated factor required for histone pre-mRNA processing.

scholarly journals Phosphorylation of Threonine 61 by Cyclin A/Cdk1 Triggers Degradation of Stem-Loop Binding Protein at the End of S Phase

2008 ◽  
Vol 28 (14) ◽  
pp. 4469-4479 ◽  
Author(s):  
M. Murat Koseoglu ◽  
Lee M. Graves ◽  
William F. Marzluff
Keyword(s):  
Cell Cycle ◽  
Fusion Proteins ◽  
Regulatory Mechanism ◽  
Binding Protein ◽  
Cyclin A ◽  
S Phase ◽  
Mrna Levels ◽  
Histone Mrna ◽  
Stem Loop

ABSTRACT Histone mRNA levels are cell cycle regulated, and a major regulatory mechanism is restriction of stem-loop binding protein (SLBP) to S phase. Degradation of SLBP at the end of S phase results in cessation of histone mRNA biosynthesis, preventing accumulation of histone mRNA until SLBP is synthesized just before entry into the next S phase. Degradation of SLBP requires an SFTTP (58 to 62) and KRKL (95 to 98) sequence, which is a putative cyclin binding site. A fusion protein with the 58-amino-acid sequence of SLBP (amino acids 51 to 108) fused to glutathione S-transferase (GST) is sufficient to mimic SLBP degradation at late S phase. Using GST-SLBP fusion proteins as a substrate, we show that cyclin A/Cdk1 phosphorylates Thr61. Furthermore, knockdown of Cdk1 by RNA interference stabilizes SLBP at the end of S phase. Phosphorylation of Thr61 is necessary for subsequent phosphorylation of Thr60 by CK2 in vitro. Inhibitors of CK2 also prevent degradation of SLBP at the end of S phase. Thus, phosphorylation of Thr61 by cyclin A/Cdk1 primes phosphorylation of Thr60 by CK2 and is responsible for initiating SLBP degradation. We conclude that the increase in cyclin A/Cdk1 activity at the end of S phase triggers degradation of SLBP at S/G2.

scholarly journals Regulation of histone mRNA in the unperturbed cell cycle: evidence suggesting control at two posttranscriptional steps.

1991 ◽  
Vol 11 (5) ◽  
pp. 2416-2424 ◽  
Author(s):  
M E Harris ◽  
R Böhni ◽  
M H Schneiderman ◽  
L Ramamurthy ◽  
D Schümperli ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Half Life ◽  
S Phase ◽  
Protein Synthesis Inhibitor ◽  
Mrna Levels ◽  
Histone Mrna ◽  
Synthesis Inhibitor ◽  
Processing Efficiency ◽  
Histone 3 ◽  
Cycle Regulation

The levels of histone mRNA increase 35-fold as selectively detached mitotic CHO cells progress from mitosis through G1 and into S phase. Using an exogenous gene with a histone 3' end which is not sensitive to transcriptional or half-life regulation, we show that 3' processing is regulated as cells progress from G1 to S phase. The half-life of histone mRNA is similar in G1- and S-phase cells, as measured after inhibition of transcription by actinomycin D (dactinomycin) or indirectly after stabilization by the protein synthesis inhibitor cycloheximide. Taken together, these results suggest that the change in histone mRNA levels between G1- and S-phase cells must be due to an increase in the rate of biosynthesis, a combination of changes in transcription rate and processing efficiency. In G2 phase, there is a rapid 35-fold decrease in the histone mRNA concentration which our results suggest is due primarily to an altered stability of histone mRNA. These results are consistent with a model for cell cycle regulation of histone mRNA levels in which the effects on both RNA 3' processing and transcription, rather than alterations in mRNA stability, are the major mechanisms by which low histone mRNA levels are maintained during G1.

Regulation of histone mRNA in the unperturbed cell cycle: evidence suggesting control at two posttranscriptional steps

1991 ◽  
Vol 11 (5) ◽  
pp. 2416-2424
Author(s):  
M E Harris ◽  
R Böhni ◽  
M H Schneiderman ◽  
L Ramamurthy ◽  
D Schümperli ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Half Life ◽  
S Phase ◽  
Protein Synthesis Inhibitor ◽  
Mrna Levels ◽  
Histone Mrna ◽  
Synthesis Inhibitor ◽  
Processing Efficiency ◽  
Histone 3 ◽  
Cycle Regulation

The levels of histone mRNA increase 35-fold as selectively detached mitotic CHO cells progress from mitosis through G1 and into S phase. Using an exogenous gene with a histone 3' end which is not sensitive to transcriptional or half-life regulation, we show that 3' processing is regulated as cells progress from G1 to S phase. The half-life of histone mRNA is similar in G1- and S-phase cells, as measured after inhibition of transcription by actinomycin D (dactinomycin) or indirectly after stabilization by the protein synthesis inhibitor cycloheximide. Taken together, these results suggest that the change in histone mRNA levels between G1- and S-phase cells must be due to an increase in the rate of biosynthesis, a combination of changes in transcription rate and processing efficiency. In G2 phase, there is a rapid 35-fold decrease in the histone mRNA concentration which our results suggest is due primarily to an altered stability of histone mRNA. These results are consistent with a model for cell cycle regulation of histone mRNA levels in which the effects on both RNA 3' processing and transcription, rather than alterations in mRNA stability, are the major mechanisms by which low histone mRNA levels are maintained during G1.

scholarly journals Drosophila Stem-Loop Binding Protein Intracellular Localization Is Mediated by Phosphorylation and Is Required for Cell Cycle-regulated Histone mRNA Expression

2004 ◽  
Vol 15 (3) ◽  
pp. 1112-1123 ◽  
Author(s):  
David J. Lanzotti ◽  
Jeremy M. Kupsco ◽  
Xiao-Cui Yang ◽  
Zbigniew Dominski ◽  
William F. Marzluff ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Rna Binding ◽  
Binding Protein ◽  
Intracellular Localization ◽  
Mrna Processing ◽  
Nuclear Targeting ◽  
Histone Mrna ◽  
Stem Loop

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.

scholarly journals Nuclear Import of the Stem–Loop Binding Protein and Localization during the Cell Cycle

2005 ◽  
Vol 16 (6) ◽  
pp. 2960-2971 ◽  
Author(s):  
Judith A. Erkmann ◽  
Eric J. Wagner ◽  
Jian Dong ◽  
Yanping Zhang ◽  
Ulrike Kutay ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Nuclear Localization ◽  
Nuclear Import ◽  
Binding Protein ◽  
Histone Mrna ◽  
Stem Loop ◽  
Histone Mrnas ◽  
Import Receptors ◽  
Mrna Binding

A key factor involved in the processing of histone pre-mRNAs in the nucleus and translation of mature histone mRNAs in the cytoplasm is the stem–loop binding protein (SLBP). In this work, we have investigated SLBP nuclear transport and subcellular localization during the cell cycle. SLBP is predominantly nuclear under steady-state conditions and localizes to the cytoplasm during S phase when histone mRNAs accumulate. Consistently, SLBP mutants that are defective in histone mRNA binding remain nuclear. As assayed in heterokaryons, export of SLBP from the nucleus is dependent on histone mRNA binding, demonstrating that SLBP on its own does not possess any nuclear export signals. We find that SLBP interacts with the import receptors Impα/Impβ and Transportin-SR2. Moreover, complexes formed between SLBP and the two import receptors are disrupted by RanGTP. We have further shown that SLBP is imported by both receptors in vitro. Three sequences in SLBP required for Impα/Impβ binding were identified. Simultaneous mutation of all three sequences was necessary to abolish SLBP nuclear localization in vivo. In contrast, we were unable to identify an in vivo role for Transportin-SR2 in SLBP nuclear localization. Thus, only the Impα/Impβ pathway contributes to SLBP nuclear import in HeLa cells.

scholarly journals Histone mRNAs Do Not Accumulate during S Phase of either Mitotic or Endoreduplicative Cycles in the Chordate Oikopleura dioica

2004 ◽  
Vol 24 (12) ◽  
pp. 5391-5403 ◽  
Author(s):  
Mariacristina Chioda ◽  
Fabio Spada ◽  
Ragnhild Eskeland ◽  
Eric M. Thompson
Keyword(s):  
Cell Cycle ◽  
S Phase ◽  
Model Organisms ◽  
Promoter Elements ◽  
Oikopleura Dioica ◽  
Stem Loop ◽  
Transcript Levels ◽  
Cell Cycles ◽  
Histone Mrnas ◽  
Complete Cell

ABSTRACT Metazoan histones are generally classified as replication-dependent or replacement variants. Replication-dependent histone genes contain cell cycle-responsive promoter elements, their transcripts terminate in an unpolyadenylated conserved stem-loop, and their mRNAs accumulate sharply during S phase. Replacement variant genes lack cell cycle-responsive promoter elements, their polyadenylated transcripts lack the stem-loop, and they are expressed at low levels throughout the cell cycle. During early development of some organisms with rapid cleavage cycles, replication-dependent mRNAs are not fully S phase restricted until complete cell cycle regulation is achieved. The accumulation of polyadenylated transcripts during this period has been considered incompatible with metazoan development. We show here that histone metabolism in the urochordate Oikopleura dioica does not accord with some key tenets of the replication-dependent/replacement variant paradigm. During the premetamorphic mitotic phase of development, expressed variants shared characteristics of replication-dependent histones, including the 3′ stem-loop, but, in contrast, were extensively polyadenylated. After metamorphosis, when cells in many tissues enter endocycles, there was a global downregulation of histone transcript levels, with most variant transcripts processed at the stem-loop. Contrary to the 30-fold S-phase upregulation of histone transcripts described in common metazoan model organisms, we observed essentially constant histone transcript levels throughout both mitotic and endoreduplicative cell cycles.

scholarly journals WEE1 kinase inhibitor AZD1775 induces CDK1 kinase-dependent origin firing in unperturbed G1- and S-phase cells

2019 ◽  
Vol 116 (48) ◽  
pp. 23891-23893 ◽  
Author(s):  
Tatiana N. Moiseeva ◽  
Chenao Qian ◽  
Norie Sugitani ◽  
Hatice U. Osmanbeyoglu ◽  
Christopher J. Bakkenist
Keyword(s):  
Cell Cycle ◽  
Clinical Trials ◽  
Cell Cycle Regulation ◽  
Kinase Inhibitor ◽  
S Phase ◽  
Origin Firing ◽  
Replicative Helicase ◽  
Origin Licensing ◽  
Wee1 Kinase ◽  
Cycle Regulation

WEE1 kinase is a key regulator of the G2/M transition. The WEE1 kinase inhibitor AZD1775 (WEE1i) induces origin firing in replicating cells. We show that WEE1i induces CDK1-dependent RIF1 phosphorylation and CDK2- and CDC7-dependent activation of the replicative helicase. WEE1 suppresses CDK1 and CDK2 kinase activities to regulate the G1/S transition after the origin licensing is complete. We identify a role for WEE1 in cell cycle regulation and important effects of AZD1775, which is in clinical trials.

Cell-cycle regulation of yeast histone mRNA

Cell ◽  
1981 ◽  
Vol 24 (2) ◽  
pp. 367-375 ◽  
Author(s):  
Lynna M. Hereford ◽  
Mary Ann Osley ◽  
J.Richard Ludwig II ◽  
Calvin S. McLaughlin
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Regulation ◽  
Histone Mrna ◽  
Cycle Regulation

scholarly journals Comprehensive Identification of Cell Cycle–regulated Genes of the YeastSaccharomyces cerevisiaeby Microarray Hybridization

1998 ◽  
Vol 9 (12) ◽  
pp. 3273-3297 ◽  
Author(s):  
Paul T. Spellman ◽  
Gavin Sherlock ◽  
Michael Q. Zhang ◽  
Vishwanath R. Iyer ◽  
Kirk Anders ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Regulation ◽  
Dna Microarrays ◽  
Full Description ◽  
Temperature Sensitive ◽  
Data Sets ◽  
Mrna Levels ◽  
Yeast Cultures ◽  
Yeast Genes ◽  
Cycle Regulation

We sought to create a comprehensive catalog of yeast genes whose transcript levels vary periodically within the cell cycle. To this end, we used DNA microarrays and samples from yeast cultures synchronized by three independent methods: α factor arrest, elutriation, and arrest of a cdc15 temperature-sensitive mutant. Using periodicity and correlation algorithms, we identified 800 genes that meet an objective minimum criterion for cell cycle regulation. In separate experiments, designed to examine the effects of inducing either the G1 cyclin Cln3p or the B-type cyclin Clb2p, we found that the mRNA levels of more than half of these 800 genes respond to one or both of these cyclins. Furthermore, we analyzed our set of cell cycle–regulated genes for known and new promoter elements and show that several known elements (or variations thereof) contain information predictive of cell cycle regulation. A full description and complete data sets are available at http://cellcycle-www.stanford.edu

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