scholarly journals Separation of intra-S checkpoint protein contributions to DNA replication fork protection and genomic stability in normal human fibroblasts

Cell Cycle ◽  
2013 ◽  
Vol 12 (2) ◽  
pp. 332-345 ◽  
Author(s):  
Stephanie L. Smith-Roe ◽  
Shivani S. Patel ◽  
Yingchun Zhou ◽  
Dennis A. Simpson ◽  
Shangbang Rao ◽  
...  
Keyword(s):  
Dna Replication ◽  
Replication Fork ◽  
Human Fibroblasts ◽  
Genomic Stability ◽  
Checkpoint Protein ◽  
Normal Human

Functional interaction between Fanconi anemia and mTOR pathways during stalled replication fork recovery

2020 ◽  
Author(s):  
Matthew Nolan ◽  
Kenneth Knudson ◽  
Marina K Holz ◽  
Indrajit Chaudhury
Keyword(s):  
Dna Repair ◽  
Dna Replication ◽  
Fanconi Anemia ◽  
Replication Fork ◽  
Genomic Stability ◽  
Repair Pathway ◽  
Functional Interaction ◽  
Mechanistic Target Of Rapamycin ◽  
Dna Strands ◽  
Repair Pathways

We have previously demonstrated that Fanconi Anemia (FA) proteins work in concert with other FA and non-FA proteins to mediate stalled replication fork restart. Previous studies suggest a connection between FA protein FANCD2 and a non-FA protein mechanistic target of rapamycin (mTOR). A recent study showed that mTOR is involved in actin-dependent DNA replication fork restart, suggesting possible roles in FA DNA repair pathway. In this study, we demonstrate that during replication stress mTOR interacts and cooperates with FANCD2 to provide cellular stability, mediates stalled replication fork restart and prevents nucleolytic degradation of the nascent DNA strands. Taken together, this study unravels a novel functional cross-talk between two important mechanisms: mTOR and FA DNA repair pathways that ensure genomic stability.

scholarly journals Key histone chaperones have distinct roles in replisome progression and genomic stability

2020 ◽  
Author(s):  
Ioannis Tsirkas ◽  
Daniel Dovrat ◽  
Yang Lei ◽  
Angeliki Kalyva ◽  
Diana Lotysh ◽  
...  
Keyword(s):  
Dna Replication ◽  
Chromatin Structure ◽  
Replication Fork ◽  
Genome Stability ◽  
Spontaneous Mutation ◽  
Genomic Stability ◽  
Yeast Cells ◽  
Eukaryotic Cells ◽  
Histone Chaperones ◽  
Replication Fork Progression

AbstractReplication-coupled (RC) nucleosome assembly is an essential process in eukaryotic cells in order to maintain chromatin structure during DNA replication. The deposition of newly synthesized H3/H4 histones during DNA replication is facilitated by specialized histone chaperones. Although the contribution of these histone chaperones to genomic stability has been thoroughly investigated, their effect on replisome progression is much less understood. By exploiting a time-lapse microscopy system for monitoring DNA replication in individual live cells, we examined how mutations in key histone chaperones including CAC1, RTT106, RTT109 and ASF1, affect replication fork progression. Our experiments revealed that mutations in CAC1 or RTT106 that directly deposit histones on the DNA, slowdown replication fork progression. In contrast, analysis of cells mutated in the intermediary ASF1 or RTT109 histone chaperones revealed that replisome progression is not affected. We found that mutations in histone chaperones including ASF1 and RTT109 lead to extended G2/M duration, elevated number of RPA foci and in some cases, increased spontaneous mutation rate. Our research suggests that histone chaperones have distinct roles in enabling high replisome progression and maintaining genome stability during cell cycle progression.Author SummaryHistone chaperones (HC) play key roles in maintaining the chromatin structure during DNA replication in eukaryotic cells. Despite extensive studies on HCs, little is known regarding their importance for replication fork progression during S-phase. Here, we utilized a live-cell imaging approach to measure the progression rates of single replication forks in individual yeast cells mutated in key histone chaperones. Using this approach, we show that mutations in CAC1 or RTT106 HCs that directly deposit histones on the DNA lead to slowdown of replication fork progression. In contrast, mutations in ASF1 or RTT109 HCs that transfers H3/H4 to CAC1 or RTT106, do not affect replisome progression but lead to post replication defects. Our results reveal distinct functions of HCs in replication fork progression and maintaining genome stability.

scholarly journals SAMHD1 promotes oncogene-induced replication stress

2020 ◽  
Author(s):  
Si Min Zhang ◽  
Jose M Calderón-Montaño ◽  
Sean G Rudd
Keyword(s):  
Cell Proliferation ◽  
Dna Damage ◽  
Overall Survival ◽  
Dna Replication ◽  
Replication Fork ◽  
Potential Role ◽  
Human Fibroblasts ◽  
Replication Stress ◽  
Oncogenic Ras ◽  
Dna Replication Stress

AbstractOncogenes induce DNA replication stress in cancer cells. Although this was established more than a decade ago, we are still unravelling the molecular underpinnings of this phenomenon, which will be critical if we are to exploit this knowledge to improve cancer treatment. A key mediator of oncogene-induced replication stress is the availability of DNA precursors, which will limit ongoing DNA synthesis by cellular replicases. In this study, we identify a potential role for nucleotide catabolism in promoting replication stress induced by oncogenes. Specifically, we establish that the dNTPase SAMHD1 slows DNA replication fork speeds in human fibroblasts harbouring an oncogenic RAS allele, elevating levels of endogenous DNA damage, and ultimately limiting cell proliferation. We then show that oncogenic RAS-driven tumours express reduced SAMHD1 levels, suggesting they have overcome this tumour suppressor barrier, and that this correlates with worse overall survival for these patients.Abstract Figure

scholarly journals Replication Fork Stalling at Natural Impediments

2007 ◽  
Vol 71 (1) ◽  
pp. 13-35 ◽  
Author(s):  
Ekaterina V. Mirkin ◽  
Sergei M. Mirkin
Keyword(s):  
Dna Replication ◽  
Replication Fork ◽  
Genetic Factors ◽  
Genomic Stability ◽  
Molecular Machines ◽  
Dna Binding Proteins ◽  
Replication Forks ◽  
Fork Stalling ◽  
Transcription Complexes

SUMMARY Accurate and complete replication of the genome in every cell division is a prerequisite of genomic stability. Thus, both prokaryotic and eukaryotic replication forks are extremely precise and robust molecular machines that have evolved to be up to the task. However, it has recently become clear that the replication fork is more of a hurdler than a runner: it must overcome various obstacles present on its way. Such obstacles can be called natural impediments to DNA replication, as opposed to external and genetic factors. Natural impediments to DNA replication are particular DNA binding proteins, unusual secondary structures in DNA, and transcription complexes that occasionally (in eukaryotes) or constantly (in prokaryotes) operate on replicating templates. This review describes the mechanisms and consequences of replication stalling at various natural impediments, with an emphasis on the role of replication stalling in genomic instability.

scholarly journals Temporal differences in DNA replication during the S phase using single fiber analysis of normal human fibroblasts and glioblastoma T98G cells

Cell Cycle ◽  
2009 ◽  
Vol 8 (19) ◽  
pp. 3133-3148 ◽  
Author(s):  
Rebecca A. Frum ◽  
Zakaria S. Khondker ◽  
David G. Kaufman
Keyword(s):  
Dna Replication ◽  
Human Fibroblasts ◽  
S Phase ◽  
Single Fiber ◽  
Temporal Differences ◽  
Fiber Analysis ◽  
Normal Human ◽  
Single Fiber Analysis

scholarly journals Precursor-Boosted Production of Metabolites in Nasturtium officinale Microshoots Grown in Plantform Bioreactors, and Antioxidant and Antimicrobial Activities of Biomass Extracts

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4660
Author(s):  
Marta Klimek-Szczykutowicz ◽  
Michał Dziurka ◽  
Ivica Blažević ◽  
Azra Đulović ◽  
Małgorzata Miazga-Karska ◽  
...  
Keyword(s):  
Photosynthetic Pigments ◽  
Human Fibroblasts ◽  
Antimicrobial Activities ◽  
Precursor Feeding ◽  
Nasturtium Officinale ◽  
Qualitative And Quantitative ◽  
Normal Human ◽  
Inhibition Zones ◽  
Ferulic Acids ◽  
Antioxidant And Antimicrobial Activities

The study demonstrated the effects of precursor feeding on the production of glucosinolates (GSLs), flavonoids, polyphenols, saccharides, and photosynthetic pigments in Nasturtium officinale microshoot cultures grown in Plantform bioreactors. It also evaluated the antioxidant and antimicrobial activities of extracts. L-phenylalanine (Phe) and L-tryptophan (Trp) as precursors were tested at 0.05, 0.1, 0.5, 1.0, and 3.0 mM. They were added at the beginning (day 0) or on day 10 of the culture. Microshoots were harvested after 20 days. Microshoots treated with 3.0 mM Phe (day 0) had the highest total GSL content (269.20 mg/100 g DW). The qualitative and quantitative profiles of the GSLs (UHPLC-DAD-MS/MS) were influenced by precursor feeding. Phe at 3.0 mM stimulated the best production of 4-methoxyglucobrassicin (149.99 mg/100 g DW) and gluconasturtiin (36.17 mg/100 g DW). Total flavonoids increased to a maximum of 1364.38 mg/100 g DW with 3.0 mM Phe (day 0), and polyphenols to a maximum of 1062.76 mg/100 g DW with 3.0 mM Trp (day 0). The precursors also increased the amounts of p-coumaric and ferulic acids, and rutoside, and generally increased the production of active photosynthetic pigments. Antioxidant potential increased the most with 0.1 mM Phe (day 0) (CUPRAC, FRAP), and with 0.5 mM Trp (day 10) (DPPH). The extracts of microshoots treated with 3.0 mM Phe (day 0) showed the most promising bacteriostatic activity against microaerobic Gram-positive acne strains (MIC 250–500 µg/mL, 20–21 mm inhibition zones). No extract was cytotoxic to normal human fibroblasts over the tested concentration range (up to 250 μg/mL).

scholarly journals Binding, internalization, and degradation of high density lipoprotein by cultured normal human fibroblasts

1977 ◽  
Vol 18 (4) ◽  
pp. 438-450
Author(s):  
N E Miller ◽  
D B Weinstein ◽  
D Steinberg
Keyword(s):  
High Density Lipoprotein ◽  
Human Fibroblasts ◽  
Density Lipoprotein ◽  
High Density ◽  
Normal Human
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