scholarly journals Role of oligouridylation in normal metabolism and regulated degradation of mammalian histone mRNAs

2018 ◽  
Vol 373 (1762) ◽  
pp. 20180170 ◽  
Author(s):  
Stacie A. Meaux ◽  
Christopher E. Holmquist ◽  
William F. Marzluff

Metazoan replication-dependent histone mRNAs are the only known cellular mRNAs that are not polyadenylated. Histone mRNAs are present in large amounts only in S-phase cells, and their levels are coordinately regulated with the rate of DNA replication. In mammals, the stemloop at the 3′ end of histone mRNA is bound to stemloop binding protein, a protein required for both synthesis and degradation of histone mRNA, and an exonuclease, 3′hExo (ERI1). Histone mRNAs are rapidly degraded when DNA synthesis is inhibited in S-phase cells and at the end of S-phase. Upf1 is also required for rapid degradation of histone mRNA as is the S-phase checkpoint. We report that Smg1 is required for histone mRNA degradation when DNA replication is inhibited, suggesting it is the PI-like kinase that activates Upf1 for histone mRNA degradation. We also show that some mutant Upf1 proteins are recruited to histone mRNAs when DNA replication is inhibited and act as dominant negative factors in histone mRNA degradation. We report that the pathway of rapid histone mRNA degradation when DNA replication is inhibited in S-phase cells that are activating the S-phase checkpoint is similar to the pathway of rapid degradation of histone mRNA at the end of S-phase. This article is part of the theme issue ‘5′ and 3′ modifications controlling RNA degradation’.

2007 ◽  
Vol 27 (17) ◽  
pp. 6053-6067 ◽  
Author(s):  
Erin Olson ◽  
Christian J. Nievera ◽  
Enbo Liu ◽  
Alan Yueh-Luen Lee ◽  
Longchuan Chen ◽  
...  

ABSTRACT The Mre11/Rad50/Nbs1 complex (MRN) plays an essential role in the S-phase checkpoint. Cells derived from patients with Nijmegen breakage syndrome and ataxia telangiectasia-like disorder undergo radioresistant DNA synthesis (RDS), failing to suppress DNA replication in response to ionizing radiation (IR). How MRN affects DNA replication to control the S-phase checkpoint, however, remains unclear. We demonstrate that MRN directly interacts with replication protein A (RPA) in unperturbed cells and that the interaction is regulated by cyclin-dependent kinases. We also show that this interaction is needed for MRN to correctly localize to replication centers. Abolishing the interaction of Mre11 with RPA leads to pronounced RDS without affecting phosphorylation of Nbs1 or SMC1 following IR. Moreover, MRN is recruited to sites at or adjacent to replication origins by RPA and acts there to inhibit new origin firing upon IR. These studies suggest a direct role of MRN at origin-proximal sites to control DNA replication initiation in response to DNA damage, thereby providing an important mechanism underlying the intra-S-phase checkpoint in mammalian cells.


2008 ◽  
Vol 180 (4) ◽  
pp. 843-843
Author(s):  
Berndt Müller ◽  
Jane Blackburn ◽  
Carmen Feijoo ◽  
Xiujie Zhao ◽  
Carl Smythe

2005 ◽  
Vol 168 (7) ◽  
pp. 999-1012 ◽  
Author(s):  
Jeff Bachant ◽  
Shannon R. Jessen ◽  
Sarah E. Kavanaugh ◽  
Candida S. Fielding

The budding yeast S phase checkpoint responds to hydroxyurea-induced nucleotide depletion by preventing replication fork collapse and the segregation of unreplicated chromosomes. Although the block to chromosome segregation has been thought to occur by inhibiting anaphase, we show checkpoint-defective rad53 mutants undergo cycles of spindle extension and collapse after hydroxyurea treatment that are distinct from anaphase cells. Furthermore, chromatid cohesion, whose dissolution triggers anaphase, is dispensable for S phase checkpoint arrest. Kinetochore–spindle attachments are required to prevent spindle extension during replication blocks, and chromosomes with two centromeres or an origin of replication juxtaposed to a centromere rescue the rad53 checkpoint defect. These observations suggest that checkpoint signaling is required to generate an inward force involved in maintaining preanaphase spindle integrity during DNA replication distress. We propose that by promoting replication fork integrity under these conditions Rad53 ensures centromere duplication. Replicating chromosomes can then bi-orient in a cohesin-independent manner to restrain untimely spindle extension.


1992 ◽  
Vol 12 (11) ◽  
pp. 5249-5259 ◽  
Author(s):  
H Xu ◽  
U J Kim ◽  
T Schuster ◽  
M Grunstein

Histone mRNA synthesis is tightly regulated to S phase of the yeast Saccharomyces cerevisiae cell cycle as a result of transcriptional and posttranscriptional controls. Moreover, histone gene transcription decreases rapidly if DNA replication is inhibited by hydroxyurea or if cells are arrested in G1 by the mating pheromone alpha-factor. To identify the transcriptional controls responsible for cycle-specific histone mRNA synthesis, we have developed a selection for mutations which disrupt this process. Using this approach, we have isolated five mutants (hpc1, hpc2, hpc3, hpc4, and hpc5) in which cell cycle regulation of histone gene transcription is altered. All of these mutations are recessive and belong to separate complementation groups. Of these, only one (hpc1) falls in one of the three complementation groups identified previously by other means (M. A. Osley and D. Lycan, Mol. Cell. Biol. 7:4204-4210, 1987), indicating that at least seven different genes are involved in the cell cycle-specific regulation of histone gene transcription. hpc4 is unique in that derepression occurs only in the presence of hydroxyurea but not alpha-factor, suggesting that at least one of the regulatory factors is specific to histone gene transcription after DNA replication is blocked. One of the hpc mutations (hpc2) suppresses delta insertion mutations in the HIS4 and LYS2 loci. This effect allowed the cloning and sequence analysis of HPC2, which encodes a 67.5-kDa, highly charged basic protein.


2009 ◽  
Vol 20 (17) ◽  
pp. 3953-3964 ◽  
Author(s):  
Eric Lau ◽  
Gary G. Chiang ◽  
Robert T. Abraham ◽  
Wei Jiang

The DNA replication machinery plays additional roles in S phase checkpoint control, although the identities of the replication proteins involved in checkpoint activation remain elusive. Here, we report that depletion of the prereplicative complex (pre-RC) protein Cdc6 causes human nontransformed diploid cells to arrest nonlethally in G1-G1/S and S phase, whereas multiple cancer cell lines undergo G1-G1/S arrest and cell death. These divergent phenotypes are dependent on the activation, or lack thereof, of an ataxia telangiectasia and Rad3-related (ATR)-dependent S phase checkpoint that inhibits replication fork progression. Although pre-RC deficiency induces chromatin structural alterations in both nontransformed and cancer cells that normally lead to ATR checkpoint activation, the sensor mechanisms in cancer cells seem to be compromised such that higher levels of DNA replication stress/damage are required to trigger checkpoint response. Our results suggest that therapy-induced disruption of pre-RC function might exert selective cytotoxic effects on tumor cells in human patients.


2008 ◽  
Vol 32 (1) ◽  
pp. 106-117 ◽  
Author(s):  
Huiqiang Lou ◽  
Makiko Komata ◽  
Yuki Katou ◽  
Zhiyun Guan ◽  
Clara C. Reis ◽  
...  

DNA Repair ◽  
2006 ◽  
Vol 5 (3) ◽  
pp. 369-380 ◽  
Author(s):  
Jen-Sing Liu ◽  
Shu-Ru Kuo ◽  
Thomas Melendy

2003 ◽  
Vol 23 (5) ◽  
pp. 1590-1601 ◽  
Author(s):  
Lianxing Zheng ◽  
Zbigniew Dominski ◽  
Xiao-Cui Yang ◽  
Phillip Elms ◽  
Christy S. Raska ◽  
...  

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.


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