scholarly journals A Double Mutant between Fission Yeast Telomerase and RecQ Helicase Is Sensitive to Thiabendazole, an Anti-Microtubule Drug

2012 ◽  
Vol 76 (2) ◽  
pp. 264-269 ◽  
Author(s):  
Shinobu UKIMORI ◽  
Naoki KAWABATA ◽  
Hideki SHIMADA ◽  
Ryota IMANO ◽  
Katsunori TAKAHASHI ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Double Mutant ◽  
Recq Helicase ◽  
Yeast Telomerase

scholarly journals Genetic suppression of defective profilin by attenuated Myosin II reveals a potential role for Myosin II in actin dynamics in vivo in fission yeast

2020 ◽  
Vol 31 (19) ◽  
pp. 2107-2114 ◽  
Author(s):  
Paola Zambon ◽  
Saravanan Palani ◽  
Shekhar Sanjay Jadhav ◽  
Pananghat Gayathri ◽  
Mohan K. Balasubramanian
Keyword(s):  
Fission Yeast ◽  
Double Mutant ◽  
Potential Role ◽  
Myosin Ii ◽  
Model Organism ◽  
Actin Dynamics ◽  
Mutant Analysis ◽  
Genetic Suppression

This work reveals an in vivo role for Myosin II in actin dynamics, potentially in its disassembly and turnover. The work uses double mutant analysis to arrive at this conclusion using the fission yeast as a model organism.

scholarly journals Effects of recJ, recQ, and recFOR Mutations on Recombination in Nuclease-Deficient recB recD Double Mutants of Escherichia coli

2005 ◽  
Vol 187 (4) ◽  
pp. 1350-1356 ◽  
Author(s):  
Ivana Ivančić-Baće ◽  
Erika Salaj-Šmic ◽  
Krunoslav Brčić-Kostić
Keyword(s):  
Escherichia Coli ◽  
Double Mutant ◽  
Reca Protein ◽  
Recq Helicase ◽  
Single Stranded Dna ◽  
Double Stranded Dna ◽  
Recf Pathway ◽  
Recombination Pathway ◽  
Recbcd Enzyme ◽  
Dna Ends

ABSTRACT The two main recombination pathways in Escherichia coli (RecBCD and RecF) have different recombination machineries that act independently in the initiation of recombination. Three essential enzymatic activities are required for early recombinational processing of double-stranded DNA ends and breaks: a helicase, a 5′→3′ exonuclease, and loading of RecA protein onto single-stranded DNA tails. The RecBCD enzyme performs all of these activities, whereas the recombination machinery of the RecF pathway consists of RecQ (helicase), RecJ (5′→3′ exonuclease), and RecFOR (RecA-single-stranded DNA filament formation). The recombination pathway operating in recB (nuclease-deficient) mutants is a hybrid because it includes elements of both the RecBCD and RecF recombination machineries. In this study, genetic analysis of recombination in a recB (nuclease-deficient) recD double mutant was performed. We show that conjugational recombination and DNA repair after UV and gamma irradiation in this mutant are highly dependent on recJ, partially dependent on recFOR, and independent of recQ. These results suggest that the recombination pathway operating in a nuclease-deficient recB recD double mutant is also a hybrid. We propose that the helicase and RecA loading activities belong to the RecBCD recombination machinery, while the RecJ-mediated 5′→3′ exonuclease is an element of the RecF recombination machinery.

scholarly journals Fission Yeast Taz1 and RPA Are Synergistically Required to Prevent Rapid Telomere Loss

2007 ◽  
Vol 18 (6) ◽  
pp. 2378-2387 ◽  
Author(s):  
Tatsuya Kibe ◽  
Yuuki Ono ◽  
Koichiro Sato ◽  
Masaru Ueno
Keyword(s):  
Fission Yeast ◽  
Binding Protein ◽  
Protein A ◽  
Telomere Maintenance ◽  
Helicase Domain ◽  
Recq Helicase ◽  
Telomeric Dna ◽  
Telomere Binding Protein ◽  
Recombination Repair ◽  
Telomere Loss

The telomere complex must allow nucleases and helicases to process chromosome ends to make them substrates for telomerase, while preventing these same activities from disrupting chromosome end-protection. Replication protein A (RPA) binds to single-stranded DNA and is required for DNA replication, recombination, repair, and telomere maintenance. In fission yeast, the telomere binding protein Taz1 protects telomeres and negatively regulates telomerase. Here, we show that taz1-d rad11-D223Y double mutants lose their telomeric DNA, indicating that RPA (Rad11) and Taz1 are synergistically required to prevent telomere loss. Telomere loss in the taz1-d rad11-D223Y double mutants was suppressed by additional mutation of the helicase domain in a RecQ helicase (Rqh1), or by overexpression of Pot1, a single-strand telomere binding protein that is essential for protection of chromosome ends. From our results, we propose that in the absence of Taz1 and functional RPA, Pot1 cannot function properly and the helicase activity of Rqh1 promotes telomere loss. Our results suggest that controlling the activity of Rqh1 at telomeres is critical for the prevention of genomic instability.

scholarly journals Genetic interactions and functional analyses of the fission yeast gsk3 and amk2 single and double mutants defective in TORC1-dependent processes

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Charalampos Rallis ◽  
StJohn Townsend ◽  
Jürg Bähler
Keyword(s):  
Fission Yeast ◽  
Double Mutant ◽  
Genetic Interaction ◽  
Genetic Network ◽  
Cellular Growth ◽  
Regulatory Subunit ◽  
Triple Mutant ◽  
Network Information ◽  
Damage Repair ◽  
Dependent Processes

Abstract The Target of Rapamycin (TOR) signalling network plays important roles in aging and disease. The AMP-activated protein kinase (AMPK) and the Gsk3 kinase inhibit TOR during stress. We performed genetic interaction screens using synthetic genetic arrays (SGA) with gsk3 and amk2 as query mutants, the latter encoding the regulatory subunit of AMPK. We identified 69 negative and 82 positive common genetic interactors, with functions related to cellular growth and stress. The 120 gsk3-specific negative interactors included genes functioning in translation and ribosomes. The 215 amk2-specific negative interactors included genes functioning in chromatin silencing and DNA damage repair. Both amk2- and gsk3-specific interactors were enriched in phenotype categories related to abnormal cell size and shape. We also performed SGA screen with the amk2 gsk3 double mutant as a query. Mutants sensitive to 5-fluorouracil, an anticancer drug are under-represented within the 305 positive interactors specific for the amk2 gsk3 query. The triple-mutant SGA screen showed higher number of negative interactions than the double mutant SGA screens and uncovered additional genetic network information. These results reveal common and specialized roles of AMPK and Gsk3 in mediating TOR-dependent processes, indicating that AMPK and Gsk3 act in parallel to inhibit TOR function in fission yeast.

scholarly journals Discrete roles of the Spc1 kinase and the Atf1 transcription factor in the UV response of Schizosaccharomyces pombe.

1997 ◽  
Vol 17 (6) ◽  
pp. 3356-3363 ◽  
Author(s):  
G Degols ◽  
P Russell
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Protein Kinase ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Uv Irradiation ◽  
Double Mutant ◽  
Uv Response ◽  
Rad Mutants ◽  
Mutant Cells

Exposure of mammalian cells to UV irradiation or alkylating agents leads to the activation of the c-Jun N-terminal kinase and p38 stress-activated protein kinase cascades, phosphorylation of c-Jun and ATF-2 bZIP transcription factors, and finally to selective induction of gene expression. This UV response is believed to be crucially important for cell survival, although conclusive evidence is lacking. Here, we address this issue by investigating a homologous UV response pathway in the fission yeast Schizosaccharomyces pombe. In fission yeast cells, UV irradiation induces activation of Spc1 stress-activated protein kinase, which in turn phosphorylates the Atf1 bZIP transcription factor. spc1 mutants are hypersensitive to killing by UV at a level equivalent to some checkpoint rad mutants. Whereas checkpoint rad mutants fail to arrest division in response to DNA damage, spc1 mutants are defective at resuming cell division after UV exposure. Levels of basal and UV-induced transcription of ctt1+, which encodes a catalase believed important for combating oxidative stress caused by UV, are extremely low in spc1 mutants. Atf1 is required for UV-induced transcription of ctt1+, but atf1 mutants are not hypersensitive to killing by UV. This surprising finding is explained by the observation that ctt1+ basal expression is unaffected in atf1 single mutant and spc1 atf1 double mutant cells, suggesting that unphosphorylated Atf1 represses ctt1+ expression in spc1 cells. In fact, the level of UV sensitivity of spc1 atf1 double mutant cells is intermediate between those of the wild type and spc1 mutants. These findings suggest the following. (i) Key properties of UV response mechanisms are remarkably similar in mammals and S. pombe. (ii) Activation of Spc1 kinase greatly enhances survival of UV-irradiated cells. (iii) Induction of gene expression by activation of Atf1 may not be the most important mechanism by which stress-activated kinases function in the UV response.

scholarly journals Structure of S. pombe telomerase protein Pof8 C-terminal domain is an xRRM conserved among LARP7 proteins

2019 ◽  
Author(s):  
Ritwika Basu ◽  
Catherine D. Eichhorn ◽  
Ryan Cheng ◽  
Juli Feigon
Keyword(s):  
Fission Yeast ◽  
Rna Binding ◽  
List Type ◽  
Core Component ◽  
Nmr Studies ◽  
Structure Comparison ◽  
Eukaryotic Chromosome ◽  
Terminal Domain ◽  
Yeast Telomerase ◽  
Definition Of

AbstractLa related proteins group 7 (LARP7) are a class of RNA chaperones that bind the 3’ends of RNA and are constitutively associated with their specific target RNAs. In metazoa, Larp7 binds to the long non-coding 7SK RNA as a core component of the 7SK RNP, a major regulator of eukaryotic transcription. In ciliates, a LARP7 protein (p65 in Tetrahymena) is a core component of telomerase, an essential ribonucleoprotein complex that maintains the DNA length at eukaryotic chromosome ends. p65 is important for the ordered assembly of telomerase RNA (TER) with telomerase reverse transcriptase (TERT). Although a LARP7 as a telomerase holoenzyme component was initially thought to be specific to ciliate telomerases, Schizosaccharomyces pombe Pof8 was recently identified as a LARP7 protein and a core component of fission yeast telomerase essential for biogenesis. There is also evidence that human Larp7 associates with telomerase. LARP7 proteins have conserved N-terminal La motif and RRM1 (La module) and C-terminal RRM2 with specific RNA substrate recognition attributed to RRM2, first structurally characterized in p65 as an atypical RRM named xRRM. Here we present the X-ray crystal structure and NMR studies of S. pombe Pof8 RRM2. Sequence and structure comparison of Pof8 RRM2 to p65 and hLarp7 xRRMs reveals conserved features for RNA binding with the main variability in the length of the non-canonical helix α3. This study shows that Pof8 has conserved xRRM features, providing insight into TER recognition and the defining characteristics of the xRRM.HighlightsThe structure of the S. pombe LARP7 Pof8 C-terminal domain is an xRRM.Ciliates, human, and fission yeast contain LARP7 proteins with xRRMs involved in telomerase biogenesis.With three examples of xRRM structures, we refine the definition of xRRM.

scholarly journals The methyl phosphate capping enzyme Bin3 is a stable component of the fission yeast telomerase holoenzyme

2021 ◽  
Author(s):  
Jennifer Porat ◽  
Moaine El Baidouri ◽  
Jorg Grigull ◽  
Jean-Marc Deragon ◽  
Mark A. Bayfield
Keyword(s):  
Fission Yeast ◽  
Genome Integrity ◽  
Methyltransferase Activity ◽  
Stable Component ◽  
U6 Snrna ◽  
Yeast Telomerase ◽  
Two Factors ◽  
Capping Enzyme ◽  
Methyl Phosphate ◽  
Insight Into

AbstractThe telomerase holoenzyme is critical for maintaining eukaryotic genome integrity. In addition to a reverse transcriptase and an RNA template, telomerase contains additional proteins that protect the telomerase RNA and promote holoenzyme assembly. Here we report that the methyl phosphate capping enzyme (MePCE) Bin3 is a stable component of the S. pombe telomerase holoenzyme. Bin3 associates with the telomerase and the U6 snRNA through an interaction with the recently described LARP7 family member Pof8, and we demonstrate that these two factors are evolutionarily linked in fungi. Our data suggest that the association of Bin3 with telomerase is independent of its methyltransferase activity, but rather that Bin3 negatively regulates TER1 levels and telomere length. Taken together, this work yields new insight into the composition, assembly, and regulation of the telomerase holoenzyme in fission yeast as well as the breadth of its evolutionary conservation.

scholarly journals Fission Yeast RecQ Helicase Rqh1 Is Required for the Maintenance of Circular Chromosomes

2014 ◽  
Vol 34 (13) ◽  
pp. 2548-2550
Author(s):  
T. Nanbu ◽  
K. Takahashi ◽  
J. M. Murray ◽  
N. Hirata ◽  
S. Ukimori ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Recq Helicase ◽  
Circular Chromosomes

scholarly journals Expression of a RecQ Helicase Homolog Affects Progression through Crisis in Fission Yeast Lacking Telomerase

2004 ◽  
Vol 280 (7) ◽  
pp. 5249-5257 ◽  
Author(s):  
Jeffrey G. Mandell ◽  
Karen J. Goodrich ◽  
Jürg Bähler ◽  
Thomas R. Cech
Keyword(s):  
Fission Yeast ◽  
Recq Helicase

scholarly journals Fission Yeast Dna2 Is Required for Generation of the Telomeric Single-Strand Overhang

2004 ◽  
Vol 24 (21) ◽  
pp. 9557-9567 ◽  
Author(s):  
Kazunori Tomita ◽  
Tatsuya Kibe ◽  
Ho-Young Kang ◽  
Yeon-Soo Seo ◽  
Masahiro Uritani ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Telomere Length ◽  
Chromatin Immunoprecipitation ◽  
Double Mutant ◽  
Gamma Ray ◽  
Strand Break ◽  
S Phase ◽  
Wild Type ◽  
Chromatin Immunoprecipitation Assay ◽  
Immunoprecipitation Assay

ABSTRACT It has been suggested that the Schizosaccharomyces pombe Rad50 (Rad50-Rad32-Nbs1) complex is required for the resection of the C-rich strand at telomere ends in taz1-d cells. However, the nuclease-deficient Rad32-D25A mutant can still resect the C-rich strand, suggesting the existence of a nuclease that resects the C-rich strand. Here, we demonstrate that a taz1-d dna2-2C double mutant lost the G-rich overhang at a semipermissive temperature. The amount of G-rich overhang in S phase in the dna2-C2 mutant was lower than that in wild-type cells at the semipermissive temperature. Dna2 bound to telomere DNA in a chromatin immunoprecipitation assay. Moreover, telomere length decreased with each generation after shift of the dna2-2C mutant to the semipermissive temperature. These results suggest that Dna2 is involved in the generation of G-rich overhangs in both wild-type cells and taz1-d cells. The dna2-C2 mutant was not gamma ray sensitive at the semipermissive temperature, suggesting that the ability to process double-strand break (DSB) ends was not affected in the dna2-C2 mutant. Our results reveal that DSB ends and telomere ends are processed by different mechanisms.

Sign in / Sign up

Export Citation Format

Share Document