scholarly journals Heterochromatin Replication: Direct Interaction of DNA replication machinery with heterochromatin code writer Clr4/Suv39 and reader Swi6/HP1 in S. pombe

2020 ◽  
Author(s):  
Sharanjot Saini ◽  
Sumit Arora ◽  
Kamlesh K. Bisht ◽  
Nandni Nakwal ◽  
Shakil Ahmed ◽  
...  
Keyword(s):  
Dna Replication ◽  
Mating Type ◽  
Central Element ◽  
Direct Interaction ◽  
Epigenetic Mark ◽  
Replication Machinery ◽  
Multiple Cell ◽  
Heterochromatin Assembly ◽  
Mitosis And Meiosis

The establishment of heterochromatin in fission yeast involves methyltransferase Clr4-mediated H3-Lys9 methylation, which is bound specifically by Swi6/HP1. However, the mechanism of propagation of heterochromatin through multiple cell divisions is not known. A role of DNA replication in propagating the heterochromatin is envisaged. Studies in S. pombe have indicated a direct interaction between DNA Polα and Swi6/HP1 and between DNA Polε and Rik1-Dos2 complex, suggesting a coupling between DNA replication and heterochromatin assembly. Here, we show that like DNA Polα, Polδ, which plays a role in both leading and lagging strand replication, also plays a role in silencing at mating type and centromere. We show that both the polymerases α and δ interact directly with both Clr4 and Swi6/HP1. Mutations in both the polymerases lead to decrease in H3-Lys9 methylation and Swi6 at the mating type and left outer repeats of centromeres I and II, with a reciprocal increase in their level at the central element, cnt, at all the three centromeres. These mutations also cause defects in chromosome segregation, recruitment of Cohesin and chromosome dynamics during mitosis and meiosis. Thus, our results indicate that a tight coordination between DNA replication machinery and propagation of the heterochromatin-specific epigenetic mark.

scholarly journals The Role of DNA Topoisomerase Binding Protein 1 (TopBP1) in Genome Stability in Arabidopsis

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2568
Author(s):  
Pablo Parra-Nunez ◽  
Claire Cooper ◽  
Eugenio Sanchez-Moran
Keyword(s):  
Dna Replication ◽  
Genome Stability ◽  
Topoisomerase Ii ◽  
Binding Protein ◽  
Dna Topoisomerase ◽  
Anaphase Bridges ◽  
Dna Replication And Repair ◽  
The Relationship ◽  
Mitosis And Meiosis

DNA topoisomerase II (TOPII) plays a very important role in DNA topology and in different biological processes such as DNA replication, transcription, repair, and chromosome condensation in higher eukaryotes. TOPII has been found to interact directly with a protein called topoisomerase II binding protein 1 (TopBP1) which also seems to have important roles in DNA replication and repair. In this study, we conducted different experiments to assess the roles of TopBP1 in DNA repair, mitosis, and meiosis, exploring the relationship between TOPII activity and TopBP1. We found that topbp1 mutant seedlings of Arabidopsis thaliana were hypersensitive to cisplatin treatment and the inhibition of TOPII with etoposide produced similar hypersensitivity levels. Furthermore, we recognised that there were no significant differences between the WT and topbp1 seedlings treated with cisplatin and etoposide together, suggesting that the hypersensitivity to cisplatin in the topbp1 mutant could be related to the functional interaction between TOPII and TopBP1. Somatic and meiotic anaphase bridges appeared in the topbp1 mutant at similar frequencies to those when TOPII was inhibited with merbarone, etoposide, or ICFR-187. The effects on meiosis of TOPII inhibition were produced at S phase/G2 stage, suggesting that catenanes could be produced at the onset of meiosis. Thus, if the processing of the catenanes is impaired, some anaphase bridges can be formed. Also, the appearance of anaphase bridges at first and second division is discussed.

scholarly journals Revisiting the role of heterochromatin protein 1 in DNA repair

2009 ◽  
Vol 185 (4) ◽  
pp. 573-575 ◽  
Author(s):  
Alexander R. Ball ◽  
Kyoko Yokomori
Keyword(s):  
Dna Damage Response ◽  
Histone H3 ◽  
Direct Interaction ◽  
Epigenetic Mark ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein ◽  
Damage Response ◽  
The One ◽  
Methylated Lysine

Heterochromatin protein 1 (HP1) is a conserved factor critical for heterochromatin organization and gene silencing. It is recruited to chromatin by its direct interaction with H3K9me (methylated lysine 9 residue of histone H3), an epigenetic mark for silenced chromatin. Now, Luijsterburg et al. (Luijsterburg, M.S., C. Dinant, H. Lans, J. Stap, E. Wiernasz, S. Lagerwerf, D.O. Warmerdam, M. Lindh, M.C. Brink, J.W. Dobrucki, et al. 2009. J. Cell Biol. 185:577–586) reveal a new H3K9me-independent role for HP1 in the DNA damage response, which is distinct from the one recently reported by Ayoub et al. (Ayoub, N., A.D. Jeyasekharan, J.A. Bernal, and A.R. Venkitaraman. 2008. Nature. 453:682–686).

Role of DNA replication in the repression of silent mating type loci in yeast

Nature ◽  
1984 ◽  
Vol 312 (5991) ◽  
pp. 247-251 ◽  
Author(s):  
Allan M. Miller ◽  
Kim A. Nasmyth
Keyword(s):  
Dna Replication ◽  
Mating Type ◽  
Silent Mating Type Loci

scholarly journals Electrical induction hypothesis to explain enhancer-promoter communication

2015 ◽  
Author(s):  
Valentina Agoni
Keyword(s):  
Transcription Factors ◽  
Dna Replication ◽  
Induction Hypothesis ◽  
Unsolved Problem ◽  
Specific Binding ◽  
Replication Machinery ◽  
Replication Process ◽  
Electrical Induction ◽  
Binding Sequence

The steps of the DNA replication process remains to be clarified. Transcription factors are supposed to find their specific binding-sequence driven by epigenetic modifications and GpC islands. But then how can the replication machinery be able to find the promoters of exactly the genes that the cell needs to transcribe in that moment? Here we hypothesize a role of DNA conductance and electrical induction to give an explanation to this unsolved problem. Our hypothesis goes in accordance with the fact that many authors identified 3D loops in the genomes.

Direct interaction between cohesin complex and DNA replication machinery

2006 ◽  
Vol 341 (3) ◽  
pp. 770-775 ◽  
Author(s):  
Min-Jung Ryu ◽  
Beom-Jun Kim ◽  
Jeong-Won Lee ◽  
Min-Woo Lee ◽  
Hyun-Kyung Choi ◽  
...  
Keyword(s):  
Dna Replication ◽  
Direct Interaction ◽  
Cohesin Complex ◽  
Replication Machinery

scholarly journals Electrical induction hypothesis to explain enhancer-promoter communication

2015 ◽  
Author(s):  
Valentina Agoni
Keyword(s):  
Transcription Factors ◽  
Dna Replication ◽  
Induction Hypothesis ◽  
Unsolved Problem ◽  
Specific Binding ◽  
Replication Machinery ◽  
Replication Process ◽  
Electrical Induction ◽  
Binding Sequence

The steps of the DNA replication process remains to be clarified. Transcription factors are supposed to find their specific binding-sequence driven by epigenetic modifications and GpC islands. But then how can the replication machinery be able to find the promoters of exactly the genes that the cell needs to transcribe in that moment? Here we hypothesize a role of DNA conductance and electrical induction to give an explanation to this unsolved problem. Our hypothesis goes in accordance with the fact that many authors identified 3D loops in the genomes.

Ionic homeostasis and subcellular element compartmentation

1990 ◽  
Vol 48 (2) ◽  
pp. 150-151
Author(s):  
Ann LeFurgey ◽  
Peter Ingram ◽  
J.J. Blum ◽  
M.C. Carney ◽  
L.A. Hawkey ◽  
...  
Keyword(s):  
Leishmania Major ◽  
Ionic Homeostasis ◽  
X Ray ◽  
Functional Studies ◽  
Cell Compartments ◽  
X Ray Imaging ◽  
Resolution Electron ◽  
Multiple Cell ◽  
Role Of Zn

Subcellular compartments commonly identified and analyzed by high resolution electron probe x-ray microanalysis (EPXMA) include mitochondria, cytoplasm and endoplasmic or sarcoplasmic reticulum. These organelles and cell regions are of primary importance in regulation of cell ionic homeostasis. Correlative structural-functional studies, based on the static probe method of EPXMA combined with biochemical and electrophysiological techniques, have focused on the role of these organelles, for example, in maintaining cell calcium homeostasis or in control of excitation-contraction coupling. New methods of real time quantitative x-ray imaging permit simultaneous examination of multiple cell compartments, especially those areas for which both membrane transport properties and element content are less well defined, e.g. nuclei including euchromatin and heterochromatin, lysosomes, mucous granules, storage vacuoles, microvilli. Investigations currently in progress have examined the role of Zn-containing polyphosphate vacuoles in the metabolism of Leishmania major, the distribution of Na, K, S and other elements during anoxia in kidney cell nuclel and lysosomes; the content and distribution of S and Ca in mucous granules of cystic fibrosis (CF) nasal epithelia; the uptake of cationic probes by mltochondria in cultured heart ceils; and the junctional sarcoplasmic retlculum (JSR) in frog skeletal muscle.

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