Unravelling the role of SNM1 in the DNA repair system ofTrypanosoma brucei

2015 ◽  
Vol 96 (4) ◽  
pp. 827-838 ◽  
Author(s):  
James A. Sullivan ◽  
Jie Lun Tong ◽  
Martin Wong ◽  
Ambika Kumar ◽  
Hajrah Sarkar ◽  
...  
Keyword(s):  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Wasim Feroz ◽  
Arwah Mohammad Ali Sheikh

Abstract Background Cells have evolved balanced mechanisms to protect themselves by initiating a specific response to a variety of stress. The TP53 gene, encoding P53 protein, is one of the many widely studied genes in human cells owing to its multifaceted functions and complex dynamics. The tumour-suppressing activity of P53 plays a principal role in the cellular response to stress. The majority of the human cancer cells exhibit the inactivation of the P53 pathway. In this review, we discuss the recent advancements in P53 research with particular focus on the role of P53 in DNA damage responses, apoptosis, autophagy, and cellular metabolism. We also discussed important P53-reactivation strategies that can play a crucial role in cancer therapy and the role of P53 in various diseases. Main body We used electronic databases like PubMed and Google Scholar for literature search. In response to a variety of cellular stress such as genotoxic stress, ischemic stress, oncogenic expression, P53 acts as a sensor, and suppresses tumour development by promoting cell death or permanent inhibition of cell proliferation. It controls several genes that play a role in the arrest of the cell cycle, cellular senescence, DNA repair system, and apoptosis. P53 plays a crucial role in supporting DNA repair by arresting the cell cycle to purchase time for the repair system to restore genome stability. Apoptosis is essential for maintaining tissue homeostasis and tumour suppression. P53 can induce apoptosis in a genetically unstable cell by interacting with many pro-apoptotic and anti-apoptotic factors. Furthermore, P53 can activate autophagy, which also plays a role in tumour suppression. P53 also regulates many metabolic pathways of glucose, lipid, and amino acid metabolism. Thus under mild metabolic stress, P53 contributes to the cell’s ability to adapt to and survive the stress. Conclusion These multiple levels of regulation enable P53 to perform diversified roles in many cell responses. Understanding the complete function of P53 is still a work in progress because of the inherent complexity involved in between P53 and its target proteins. Further research is required to unravel the mystery of this Guardian of the genome “TP53”.


2021 ◽  
Author(s):  
Marisol Giustozzi ◽  
Santiago Freytes ◽  
Aime Jaskolowski ◽  
Micaela Lichy ◽  
Julieta L. Mateos ◽  
...  

Mediator 17 (MED17) is a subunit of the Mediator complex that regulates transcription initiation in eukaryotic organisms. In yeast and humans, MED17 also participates in DNA repair, physically interacting with proteins of the Nucleotide Excision DNA Repair system. We here analyzed the role of MED17 in Arabidopsis plants exposed to UV-B radiation, which role has not been previously described. Comparison of med17 mutant transcriptome to that of WT plants showed that almost one third of transcripts with altered expression in med17 plants are also changed by UV-B exposure in WT plants. To validate the role of MED17 in UV-B irradiated plants, plant responses to UV-B were analyzed, including flowering time, DNA damage accumulation and programmed cell death in the meristematic cells of the root tips. Our results show that med17 and OE MED17 plants have altered responses to UV-B; and that MED17 participates in various aspects of the DNA damage response (DDR). Increased sensitivity to DDR after UV-B in med17 plants can be due to altered regulation of UV-B responsive transcripts; but additionally MED17 physically interacts with DNA repair proteins, suggesting a direct role of this Mediator subunit during repair. Finally, we here also show that MED17 is necessary to regulate the DDR activated by ATR, and that PDCD5 overexpression reverts the deficiencies in DDR shown in med17 mutants. Together, the data presented demonstrates that MED17 is an important regulator of the DDR after UV-B radiation in Arabidopsis plants.


Life Sciences ◽  
2020 ◽  
Vol 262 ◽  
pp. 118562
Author(s):  
Mohammad Yousef Memar ◽  
Mina Yekani ◽  
Giuseppe Celenza ◽  
Vahdat Poortahmasebi ◽  
Behrooz Naghili ◽  
...  

2021 ◽  
Author(s):  
Nilabhra Mitra ◽  
Sanghamitra Dey

The role of sirtuins in plants are slowly unraveling. There are only reports of H3K9Ac deacetylation by OsSRT1. Here our studies shade light on its dual enzyme capability with preference for mono ADP ribosylation over deacetylation. OsSRT1 can specifically transfer the single ADP ribose group on its substrates in an enzymatic manner. This mono ADPr effect is not well known in plants, more so for deacetylases. The products of this reaction (NAM and ADP ribose) have immense negative effect on this enzyme suggesting a tighter regulation. Resveratrol, a natural plant polyphenol proves to be a strong activator of this enzyme at 150 μM concentration. Under different abiotic stress conditions, we could link this ADP ribosylase activity to the DNA repair pathway by activating the enzyme PARP1. Metal stress in plants also influences these enzyme activities.


2004 ◽  
Vol 186 (19) ◽  
pp. 6485-6491 ◽  
Author(s):  
Mario Pedraza-Reyes ◽  
Ronald E. Yasbin

ABSTRACT A reversion assay system previously implemented to demonstrate the existence of adaptive or stationary-phase-induced mutagenesis in Bacillus subtilis was utilized in this report to study the influence of the mismatch DNA repair (MMR) system on this type of mutagenesis. Results revealed that a strain deficient in MutSL showed a significant propensity to generate increased numbers of stationary-phase-induced revertants. These results suggest that absence or depression of MMR is an important factor in the mutagenesis of nongrowing B. subtilis cells because of the role of MMR in repairing DNA damage. In agreement with this suggestion, a significant decrease in the number of adaptive revertant colonies, for the three markers tested, occurred in B. subtilis cells which overexpressed a component of the MMR system. Interestingly, the single overexpression of mutS, but not of mutL, was sufficient to decrease the level of adaptive mutants in the reversion assay system of B. subtilis. The results presented in this work, as well as in our previous studies, appear to suggest that an MMR deficiency, putatively attributable to inactivation or saturation with DNA damage of MutS, may occur in a subset of B. subtilis cells that differentiate into the hypermutable state.


2012 ◽  
Vol 31 (7) ◽  
pp. 1182-1186 ◽  
Author(s):  
Joana Silva ◽  
Ana L. Teixeira ◽  
Francisco Lobo ◽  
Joaquina Maurício ◽  
Rui Medeiros

Author(s):  
V. N. Babakov ◽  
N. Yu. Rogovskaya ◽  
I. D. Kurdyukov ◽  
P. P. Beltyukov ◽  
S. A. Dulov ◽  
...  

The effect of aryl hydrocarbon receptor agonists (FICZ and ITE), as well as lipopolysaccharide under the toxic action of benzo(a)pyrene in HepaRG human hepatoma cells was evaluated. Active forms of the key stress-activated kinase cascades and DNA repair system proteins were used as markers of the genotoxic action of benzo(a)pyrene. A mixture of lipopolysaccharide with benzo(a)pyrene increases benzo(a)pyrene cytotoxicity and reduces the activation of DNA repair system proteins below the control level. Aryl hydrocarbon receptor agonists (FICZ and ITE) exhibit a cytoprotective effect against benzo(a) pyrene, enhance Akt1 kinase activation, and downregulate activation of the p53 protein and Chk1 and Chk2 checkpoint kinases. Thus, FICZ and ITE reduce the genotoxicity of benzo(a)pyrene.


2019 ◽  
Vol 116 (3) ◽  
pp. 76a
Author(s):  
Manasvita Vashisth ◽  
Sangkyun Cho ◽  
Dennis Discher

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