scholarly journals Comparative analysis of different laser systems to study cellular responses to DNA damage in mammalian cells

2009 ◽  
Vol 37 (9) ◽  
pp. e68-e68 ◽  
Author(s):  
Xiangduo Kong ◽  
Samarendra K. Mohanty ◽  
Jared Stephens ◽  
Jason T. Heale ◽  
Veronica Gomez-Godinez ◽  
...  
Keyword(s):  
Dna Damage ◽  
Comparative Analysis ◽  
Mammalian Cells ◽  
Cellular Responses ◽  
Laser Systems

scholarly journals Application of Laser Microirradiation in the Investigations of Cellular Responses to DNA Damage

2021 ◽  
Vol 8 ◽  
Author(s):  
Xiangduo Kong ◽  
Nicole M. Wakida ◽  
Kyoko Yokomori
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Mammalian Cells ◽  
Cellular Responses ◽  
Future Application ◽  
Cellular Processes ◽  
Damage Response ◽  
Different Types ◽  
Laser Systems ◽  
Laser Microirradiation

Since the laser has been invented it has been highly instrumental in ablating different parts of the cell to test their functionality. Through induction of damage in a defined sub-micron region in the cell nucleus, laser microirradiation technique is now established as a powerful real-time and high-resolution methodology to investigate mechanisms of DNA damage response and repair, the fundamental cellular processes for the maintenance of genomic integrity, in mammalian cells. However, irradiation conditions dictate the amounts, types and complexity of DNA damage, leading to different damage signaling responses. Thus, in order to properly interpret the results, it is important to understand the features of laser-induced DNA damage. In this review, we describe different types of DNA damage induced by the use of different laser systems and parameters, and discuss the mechanisms of DNA damage induction. We further summarize recent advances in the application of laser microirradiation to study spatiotemporal dynamics of cellular responses to DNA damage, including factor recruitment, chromatin modulation at damage sites as well as more global damage signaling. Finally, possible future application of laser microirradiation to gain further understanding of DNA damage response will be discussed.

Inducible Cellular Responses to DNA Damage in Mammalian Cells

1986 ◽  
pp. 291-311 ◽  
Author(s):  
Michael E. Lambert ◽  
James I. Garrels ◽  
John McDonald ◽  
I. Bernard Weinstein
Keyword(s):  
Dna Damage ◽  
Mammalian Cells ◽  
Cellular Responses

Regulation and mechanisms of gene amplification

1995 ◽  
Vol 347 (1319) ◽  
pp. 49-56 ◽  
Keyword(s):  
Dna Damage ◽  
Genetic Analysis ◽  
Mammalian Cells ◽  
Chromosome Breakage ◽  
Cellular Responses ◽  
Human Cells ◽  
Aspartate Transcarbamylase ◽  
Tumour Suppressor Function ◽  
Damage Recognition ◽  
Sister Chromatids

Amplification in rodent cells usually involves bridge-breakage-fusion (bbf) cycles initiated either by endto-end fusion of sister chromatids, or by chromosome breakage. In contrast, in human cells, resistance to the antimetabolite A-(phosphonacetyl)-L-aspartate (PALA) can be mediated by several different mechanisms that lead to overexpression of the target enzyme carbamyl-P synthetase, aspartate transcarbamylase, dihydro-orotase (CAD). Mechanisms involving bbf cycles account for only a minority of CAD amplification events in the human fibrosarcoma cell line HT 1080. Here, formation of a 2p isochromosome and overexpression of CAD by other types of amplification events (and even without amplification) are much more prevalent. Broken DNA is recognized by mammalian cells with intact damage-recognition pathways, as a signal to arrest or to die. Loss of these pathways by, for example, loss of p53 or pRb tumour suppressor function, or by increased expression of ras and myc oncogenes, causes non-permissive rat and human cells to become permissive both for amplification and for other manifestations of DNA damage. In cells that are already permissive, amplification can be stimulated by overexpressing oncogenes such as c-myc or ras , or by damaging DNA in a variety of ways. To supplement genetic analysis of amplification in mammalian cells, an amplification selection has been established in Schizosaccharomyces pombe . Selection with LiCl yields cells with amplified sod2 genes in structures related to those observed in mammalian cells. The effect on amplification in S. pombe can now be tested for any mutation in a gene involved in repair of damaged DNA or in normal cellular responses to DNA damage.

scholarly journals The poly(ADP-ribose)-dependent chromatin remodeler Alc1 induces local chromatin relaxation upon DNA damage

2016 ◽  
Vol 27 (24) ◽  
pp. 3791-3799 ◽  
Author(s):  
Hafida Sellou ◽  
Théo Lebeaupin ◽  
Catherine Chapuis ◽  
Rebecca Smith ◽  
Anna Hegele ◽  
...  
Keyword(s):  
Dna Damage ◽  
Structural Changes ◽  
Cellular Responses ◽  
Dna Lesions ◽  
Fast Kinetics ◽  
Important Player ◽  
Chromatin Relaxation ◽  
Kinetics Of ◽  
Laser Microirradiation

Chromatin relaxation is one of the earliest cellular responses to DNA damage. However, what determines these structural changes, including their ATP requirement, is not well understood. Using live-cell imaging and laser microirradiation to induce DNA lesions, we show that the local chromatin relaxation at DNA damage sites is regulated by PARP1 enzymatic activity. We also report that H1 is mobilized at DNA damage sites, but, since this mobilization is largely independent of poly(ADP-ribosyl)ation, it cannot solely explain the chromatin relaxation. Finally, we demonstrate the involvement of Alc1, a poly(ADP-ribose)- and ATP-dependent remodeler, in the chromatin-relaxation process. Deletion of Alc1 impairs chromatin relaxation after DNA damage, while its overexpression strongly enhances relaxation. Altogether our results identify Alc1 as an important player in the fast kinetics of the NAD+- and ATP-dependent chromatin relaxation upon DNA damage in vivo.

scholarly journals Tethering DNA Damage Checkpoint Mediator Proteins Topoisomerase IIβ-binding Protein 1 (TopBP1) and Claspin to DNA Activates Ataxia-Telangiectasia Mutated and RAD3-related (ATR) Phosphorylation of Checkpoint Kinase 1 (Chk1)

2011 ◽  
Vol 286 (22) ◽  
pp. 19229-19236 ◽  
Author(s):  
Laura A. Lindsey-Boltz ◽  
Aziz Sancar
Keyword(s):  
Dna Damage ◽  
Ataxia Telangiectasia ◽  
Mammalian Cells ◽  
Binding Protein ◽  
Effector Proteins ◽  
Ataxia Telangiectasia Mutated ◽  
Checkpoint Kinase ◽  
Atr Kinase

The ataxia-telangiectasia mutated and RAD3-related (ATR) kinase initiates DNA damage signaling pathways in human cells after DNA damage such as that induced upon exposure to ultraviolet light by phosphorylating many effector proteins including the checkpoint kinase Chk1. The conventional view of ATR activation involves a universal signal consisting of genomic regions of replication protein A-covered single-stranded DNA. However, there are some indications that the ATR-mediated checkpoint can be activated by other mechanisms. Here, using the well defined Escherichia coli lac repressor/operator system, we have found that directly tethering the ATR activator topoisomerase IIβ-binding protein 1 (TopBP1) to DNA is sufficient to induce ATR phosphorylation of Chk1 in an in vitro system as well as in vivo in mammalian cells. In addition, we find synergistic activation of ATR phosphorylation of Chk1 when the mediator protein Claspin is also tethered to the DNA with TopBP1. Together, these findings indicate that crowding of checkpoint mediator proteins on DNA is sufficient to activate the ATR kinase.

scholarly journals Dephosphorylation of the C-terminal Tyrosyl Residue of the DNA Damage-related Histone H2A.X Is Mediated by the Protein Phosphatase Eyes Absent

2009 ◽  
Vol 284 (24) ◽  
pp. 16066-16070 ◽  
Author(s):  
Navasona Krishnan ◽  
Dae Gwin Jeong ◽  
Suk-Kyeong Jung ◽  
Seong Eon Ryu ◽  
Andrew Xiao ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Mammalian Cells ◽  
Protein Tyrosine Phosphatases ◽  
Histone H2a ◽  
Eyes Absent ◽  
Damage Repair ◽  
Damage Response

In mammalian cells, the DNA damage-related histone H2A variant H2A.X is characterized by a C-terminal tyrosyl residue, Tyr-142, which is phosphorylated by an atypical kinase, WSTF. The phosphorylation status of Tyr-142 in H2A.X has been shown to be an important regulator of the DNA damage response by controlling the formation of γH2A.X foci, which are platforms for recruiting molecules involved in DNA damage repair and signaling. In this work, we present evidence to support the identification of the Eyes Absent (EYA) phosphatases, protein-tyrosine phosphatases of the haloacid dehalogenase superfamily, as being responsible for dephosphorylating the C-terminal tyrosyl residue of histone H2A.X. We demonstrate that EYA2 and EYA3 displayed specificity for Tyr-142 of H2A.X in assays in vitro. Suppression of eya3 by RNA interference resulted in elevated basal phosphorylation and inhibited DNA damage-induced dephosphorylation of Tyr-142 of H2A.X in vivo. This study provides the first indication of a physiological substrate for the EYA phosphatases and suggests a novel role for these enzymes in regulation of the DNA damage response.

Cellular Responses to DNA Damage and Human Chromosome Instability Syndromes

1998 ◽  
pp. 395-442 ◽  
Author(s):  
KumKum Khanna ◽  
Richard Gatti ◽  
Patrick Concannon ◽  
Corry M. R. Weemaes ◽  
Merl F. Hoekstra ◽  
...  
Keyword(s):  
Dna Damage ◽  
Human Chromosome ◽  
Chromosome Instability ◽  
Cellular Responses
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