scholarly journals Retinal Degeneration and Ionizing Radiation Hypersensitivity in a Mouse Model for Cockayne Syndrome

2006 ◽  
Vol 27 (4) ◽  
pp. 1433-1441 ◽  
Author(s):  
Theo G. M. F. Gorgels ◽  
Ingrid van der Pluijm ◽  
Renata M. C. Brandt ◽  
George A. Garinis ◽  
Harry van Steeg ◽  
...  
Keyword(s):  
Ionizing Radiation ◽  
Mouse Model ◽  
Photoreceptor Cells ◽  
Cockayne Syndrome ◽  
Dna Lesions ◽  
Premature Aging ◽  
Oxidative Stress Marker ◽  
Marker Genes ◽  
Uv Sensitivity ◽  
Transcription Coupled Repair

ABSTRACT Mutations in the CSB gene cause Cockayne syndrome (CS), a DNA repair disorder characterized by UV sensitivity and severe physical and neurological impairment. CSB functions in the transcription-coupled repair subpathway of nucleotide excision repair. This function may explain the UV sensitivity but hardly clarifies the other CS symptoms. Many of these, including retinopathy, are associated with premature aging. We studied eye pathology in a mouse model for CS. Csb m/m mice were hypersensitive to UV light and developed epithelial hyperplasia and squamous cell carcinomas in the cornea, which underscores the importance of transcription-coupled repair of photolesions in the mouse. In addition, we observed a spontaneous loss of retinal photoreceptor cells with age in the Csb m/m retina, resulting in a 60% decrease in the number of rods by the age of 18 months. Importantly, when Csb m/m mice (as well as Csa −/− mice) were exposed to 10 Gy of ionizing radiation, we noticed an increase in apoptotic photoreceptor cells, which was not observed in wild-type animals. This finding, together with our observation that the expression of established oxidative stress marker genes is upregulated in the Csb m/m retina, suggests that (endogenous) oxidative DNA lesions play a role in this CS-specific premature-aging feature and supports the oxidative DNA damage theory of aging.

scholarly journals Oxygen-Dependent Accumulation of Purine DNA Lesions in Cockayne Syndrome Cells

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1671 ◽  
Author(s):  
Marios G. Krokidis ◽  
Mariarosaria D’Errico ◽  
Barbara Pascucci ◽  
Eleonora Parlanti ◽  
Annalisa Masi ◽  
...  
Keyword(s):  
Dna Damage ◽  
Oxidative Dna Damage ◽  
Excision Repair ◽  
Enzymatic Digestion ◽  
Cockayne Syndrome ◽  
Dna Lesions ◽  
Premature Aging ◽  
Neurological Features ◽  
Oxygen Tensions ◽  
Base Excision

Cockayne Syndrome (CS) is an autosomal recessive neurodegenerative premature aging disorder associated with defects in nucleotide excision repair (NER). Cells from CS patients, with mutations in CSA or CSB genes, present elevated levels of reactive oxygen species (ROS) and are defective in the repair of a variety of oxidatively generated DNA lesions. In this study, six purine lesions were ascertained in wild type (wt) CSA, defective CSA, wtCSB and defective CSB-transformed fibroblasts under different oxygen tensions (hyperoxic 21%, physioxic 5% and hypoxic 1%). In particular, the four 5′,8-cyclopurine (cPu) and the two 8-oxo-purine (8-oxo-Pu) lesions were accurately quantified by LC-MS/MS analysis using isotopomeric internal standards after an enzymatic digestion procedure. cPu levels were found comparable to 8-oxo-Pu in all cases (3–6 lesions/106 nucleotides), slightly increasing on going from hyperoxia to physioxia to hypoxia. Moreover, higher levels of four cPu were observed under hypoxia in both CSA and CSB-defective cells as compared to normal counterparts, along with a significant enhancement of 8-oxo-Pu. These findings revealed that exposure to different oxygen tensions induced oxidative DNA damage in CS cells, repairable by NER or base excision repair (BER) pathways. In NER-defective CS patients, these results support the hypothesis that the clinical neurological features might be connected to the accumulation of cPu. Moreover, the elimination of dysfunctional mitochondria in CS cells is associated with a reduction in the oxidative DNA damage.

scholarly journals CSB-Dependent Cyclin-Dependent Kinase 9 Degradation and RNA Polymerase II Phosphorylation during Transcription-Coupled Repair

2019 ◽  
Vol 39 (6) ◽  
Author(s):  
Lise-Marie Donnio ◽  
Anna Lagarou ◽  
Gabrielle Sueur ◽  
Pierre-Olivier Mari ◽  
Giuseppina Giglia-Mari
Keyword(s):  
Dna Repair ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Uv Irradiation ◽  
Dna Lesions ◽  
Premature Aging ◽  
Cyclin Dependent Kinase ◽  
Cyclin T1 ◽  
Group B ◽  
Transcription Coupled Repair

ABSTRACT DNA lesions block cellular processes such as transcription, inducing apoptosis, tissue failures, and premature aging. To counteract the deleterious effects of DNA damage, cells are equipped with various DNA repair pathways. Transcription-coupled repair specifically removes helix-distorting DNA adducts in a coordinated multistep process. This process has been extensively studied; however, once the repair reaction is accomplished, little is known about how transcription restarts. In this study, we show that, after UV irradiation, the cyclin-dependent kinase 9 (CDK9)/cyclin T1 kinase unit is specifically released from the HEXIM1 complex and that this released fraction is degraded in the absence of the Cockayne syndrome group B protein (CSB). We determine that UV irradiation induces a specific Ser2 phosphorylation of the RNA polymerase II and that this phosphorylation is CSB dependent. Surprisingly, CDK9 is not responsible for this phosphorylation but instead might play a nonenzymatic role in transcription restart after DNA repair.

scholarly journals Immunofluorescence studies to dissect the impact of Cockayne syndrome A alterations on the protein interaction and cellular localization

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Amr Ghit
Keyword(s):  
Cellular Localization ◽  
Excision Repair ◽  
Growth Failure ◽  
Autosomal Recessive Disorder ◽  
Cockayne Syndrome ◽  
Dna Lesions ◽  
Premature Aging ◽  
Neurological Dysfunction ◽  
C Terminus ◽  
The Impact

Abstract Background Cockayne syndrome (CS), which was discovered by Alfred Cockayne nearly 75 years ago, is a rare autosomal recessive disorder characterized by growth failure, neurological dysfunction, premature aging, and other clinical features including microcephaly, ophthalmologic abnormalities, dental caries, and cutaneous photosensitivity. These alterations are caused by mutations in the CSA or CSB genes, both of which are involved in transcription-coupled nucleotide excision repair (TC-NER), the sub-pathway of NER that rapidly removes UV-induced DNA lesions which block the progression of the transcription machinery in the transcribed strand of active genes. Several studies assumed that CSA and CSB genes can play additional roles outside TC-NER, due to the wide variations in type and severity of the CS phenotype and the lack of a clear relationship between genotype and phenotype. To address this issue, our lab generated isogenic cell lines expressing wild type as well as different versions of mutated CSA proteins, fused at the C-terminus with the Flag and HA epitope tags (CSAFlag-HA). In unpublished data, the identity of the CSA-interacting proteins was determined by mass spectrometry. Among which three subunits (namely, CCT3, CCT8, and TCP1) of the TRiC/CCT complex appeared as novel interactors. TRiC is a chaperonin involved in the folding of newly synthesized or unfolded proteins. The aim of this study is directed to investigate by immunofluorescence analysis the impact of the selected CSA mutations on the subcellular localization of the CSA protein itself as well as on its novel interactors CCT3, CCT8, and TCP1. Results We showed that specific CSA mutations impair the proper cellular localization of the protein, but have no impact on the cellular distribution of the TRiC subunits or CSA/TRiC co-localization. Conclusion We suggested that the activity of the TRiC complex does not rely on the functionality of CSA.

scholarly journals The SRS2 suppressor of rad6 mutations of Saccharomyces cerevisiae acts by channeling DNA lesions into the RAD52 DNA repair pathway.

Genetics ◽  
1990 ◽  
Vol 124 (4) ◽  
pp. 817-831 ◽  
Author(s):  
R H Schiestl ◽  
S Prakash ◽  
L Prakash
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Repair ◽  
Gamma Ray ◽  
Dna Lesions ◽  
Recombinational Repair ◽  
Repair Pathway ◽  
Uv Mutagenesis ◽  
Uv Sensitivity ◽  
Suppressor Mutations ◽  
Induced Mutagenesis

Abstract rad6 mutants of Saccharomyces cerevisiae are defective in the repair of damaged DNA, DNA damage induced mutagenesis, and sporulation. In order to identify genes that can substitute for RAD6 function, we have isolated genomic suppressors of the UV sensitivity of rad6 deletion (rad6 delta) mutations and show that they also suppress the gamma-ray sensitivity but not the UV mutagenesis or sporulation defects of rad6. The suppressors show semidominance for suppression of UV sensitivity and dominance for suppression of gamma-ray sensitivity. The six suppressor mutations we isolated are all alleles of the same locus and are also allelic to a previously described suppressor of the rad6-1 nonsense mutation, SRS2. We show that suppression of rad6 delta is dependent on the RAD52 recombinational repair pathway since suppression is not observed in the rad6 delta SRS2 strain containing an additional mutation in either the RAD51, RAD52, RAD54, RAD55 or RAD57 genes. Possible mechanisms by which SRS2 may channel unrepaired DNA lesions into the RAD52 DNA repair pathway are discussed.

scholarly journals Immunocytes as a Biocarrier to Delivery Therapeutic and Imaging Contrast Agents to Tumors

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Jinhyang Choi ◽  
Ha-Na Woo ◽  
Eun Jin Ju ◽  
Joohee Jung ◽  
Hye-Kyung Chung ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Ionizing Radiation ◽  
Mouse Model ◽  
Cancer Treatment ◽  
Anticancer Agents ◽  
Anticancer Agent ◽  
Human Cancer ◽  
Genetic Alterations ◽  
Therapeutic Effects ◽  
Ionizing Radiation Exposure

Radiotherapy for cancer treatment has been used for primary or adjuvant treatment in many types of cancer, and approximately half of all cancer patients are undergoing radiation. However, ionizing radiation exposure induces genetic alterations in cancer cells and results in recruitment of monocytes/macrophages by triggering signals released from these cells. Using this characteristic of monocytes/macrophages, we have attempted to develop a biocarrier loading radiosensitizing anticancer agents that can lead to enhance the therapeutic effect of radiation in cancer treatment. The aim of this study is to demonstrate the proof of this concept. THP-1 labeled with Qdot 800 or iron oxide (IO) effectively migrated into tumors of subcutaneous mouse model and increased recruitment after ionizing radiation. Functionalized liposomes carrying a radiosensitizing anticancer agent, doxorubicin, are successfully loaded in THP-1 (THP-1-LP-Dox) with reduced cytotoxicity, and THP-1-LP-Dox also was observed in tumors after intravenous administration. Here, we report that monocytes/macrophages as a biocarrier can be used as a selective tool for amplification of the therapeutic effects on radiotherapy for human cancer treatment.

scholarly journals An Xpd mouse model for the combined xeroderma pigmentosum/Cockayne syndrome exhibiting both cancer predisposition and segmental progeria

Cancer Cell ◽  
2006 ◽  
Vol 10 (2) ◽  
pp. 121-132 ◽  
Author(s):  
Jaan-Olle Andressoo ◽  
James R. Mitchell ◽  
Jan de Wit ◽  
Deborah Hoogstraten ◽  
Marcel Volker ◽  
...  
Keyword(s):  
Mouse Model ◽  
Xeroderma Pigmentosum ◽  
Cockayne Syndrome ◽  
Cancer Predisposition

scholarly journals Recognition of RNA Polymerase II and Transcription Bubbles by XPG, CSB, and TFIIH: Insights for Transcription-Coupled Repair and Cockayne Syndrome

2005 ◽  
Vol 20 (2) ◽  
pp. 187-198 ◽  
Author(s):  
Altaf H. Sarker ◽  
Susan E. Tsutakawa ◽  
Seth Kostek ◽  
Cliff Ng ◽  
David S. Shin ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Cockayne Syndrome ◽  
Transcription Coupled Repair

scholarly journals Inhibition of Rac1 attenuates radiation-induced lung injury while suppresses lung tumor in mice

2022 ◽  
Vol 8 (1) ◽  
Author(s):  
Ni An ◽  
Zhenjie Li ◽  
Xiaodi Yan ◽  
Hainan Zhao ◽  
Yajie Yang ◽  
...  
Keyword(s):  
Ionizing Radiation ◽  
Lung Injury ◽  
Mouse Model ◽  
Tumor Cells ◽  
Nuclear Translocation ◽  
Lung Tumor ◽  
Lung Epithelial Cells ◽  
Normal Lung ◽  
Limiting Factor ◽  
Radiation Induced

AbstractThe lung is one of the most sensitive tissues to ionizing radiation, thus, radiation-induced lung injury (RILI) stays a key dose-limiting factor of thoracic radiotherapy. However, there is still little progress in the effective treatment of RILI. Ras-related C3 botulinum toxin substrate1, Rac1, is a small guanosine triphosphatases involved in oxidative stress and apoptosis. Thus, Rac1 may be an important molecule that mediates radiation damage, inhibition of which may produce a protective effect on RILI. By establishing a mouse model of radiation-induced lung injury and orthotopic lung tumor-bearing mouse model, we detected the role of Rac1 inhibition in the protection of RILI and suppression of lung tumor. The results showed that ionizing radiation induces the nuclear translocation of Rac1, the latter then promotes nuclear translocation of P53 and prolongs the residence time of p53 in the nucleus, thereby promoting the transcription of Trp53inp1 which mediates p53-dependent apoptosis. Inhibition of Rac1 significantly reduce the apoptosis of normal lung epithelial cells, thereby effectively alleviating RILI. On the other hand, inhibition of Rac1 could also significantly inhibit the growth of lung tumor, increase the radiation sensitivity of tumor cells. These differential effects of Rac1 inhibition were related to the mutation and overexpression of Rac1 in tumor cells.

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