Detecting A Novel Motif of O6-methyl guanine DNA Methyltransferase, a DNA Repair Enzyme, Involved in Interaction with Proliferating Cell Nuclear Antigen Through a Computer Modeling Approach

2021 ◽  
pp. 113471
Author(s):  
Marzieh Gharouni ◽  
Hamid Mosaddeghi ◽  
Jamshid Mehrzad ◽  
Ali Es-haghi ◽  
Alireza Motavalizadehkakhky
Keyword(s):  
Dna Repair ◽  
Computer Modeling ◽  
Proliferating Cell Nuclear Antigen ◽  
Dna Methyltransferase ◽  
Nuclear Antigen ◽  
Repair Enzyme ◽  
Modeling Approach ◽  
Proliferating Cell

scholarly journals Human SHPRH suppresses genomic instability through proliferating cell nuclear antigen polyubiquitination

2006 ◽  
Vol 175 (5) ◽  
pp. 703-708 ◽  
Author(s):  
Akira Motegi ◽  
Raman Sood ◽  
Helen Moinova ◽  
Sanford D. Markowitz ◽  
Pu Paul Liu ◽  
...  
Keyword(s):  
Dna Repair ◽  
Genomic Instability ◽  
Proliferating Cell Nuclear Antigen ◽  
Genotoxic Stress ◽  
Suppressor Gene ◽  
Nuclear Antigen ◽  
Putative Tumor Suppressor Gene ◽  
Ubiquitin Ligase E3 ◽  
Proliferating Cell ◽  
Dependent Pathway

Differential modifications of proliferating cell nuclear antigen (PCNA) determine DNA repair pathways at stalled replication forks. In yeast, PCNA monoubiquitination by the ubiquitin ligase (E3) yRad18 promotes translesion synthesis (TLS), whereas the lysine-63–linked polyubiquitination of PCNA by yRad5 (E3) promotes the error-free mode of bypass. The yRad5-dependent pathway is important to prevent genomic instability during replication, although its exact molecular mechanism is poorly understood. This mechanism has remained totally elusive in mammals because of the lack of apparent RAD5 homologues. We report that a putative tumor suppressor gene, SHPRH, is a human orthologue of yeast RAD5. SHPRH associates with PCNA, RAD18, and the ubiquitin-conjugating enzyme UBC13 (E2) and promotes methyl methanesulfonate (MMS)–induced PCNA polyubiquitination. The reduction of SHPRH by stable short hairpin RNA increases sensitivity to MMS and enhances genomic instability. Therefore, the yRad5/SHPRH-dependent pathway is a conserved and fundamental DNA repair mechanism that protects the genome from genotoxic stress.

scholarly journals Changes in cyclin/proliferating cell nuclear antigen distribution during DNA repair synthesis.

1988 ◽  
Vol 107 (5) ◽  
pp. 1623-1628 ◽  
Author(s):  
L Toschi ◽  
R Bravo
Keyword(s):  
Dna Repair ◽  
Uv Irradiation ◽  
Proliferating Cell Nuclear Antigen ◽  
Human Fibroblasts ◽  
Immunofluorescent Staining ◽  
Nuclear Antigen ◽  
Nuclear Staining ◽  
Repair Synthesis ◽  
Dna Repair Synthesis ◽  
Proliferating Cell

UV irradiation of quiescent human fibroblasts immediately triggers the appearance of the nuclear protein cyclin/proliferating cell nuclear antigen (PCNA) as detected by indirect immunofluorescent staining after methanol fixation. This was found to be independent of new synthesis of cyclin/PCNA by two-dimensional gel analysis and cycloheximide treatment. The intensity of the immunofluorescent staining of cyclin/PCNA observed in UV-irradiated cells corresponded with the UV dose used and with the DNA repair synthesis detected by autoradiography. The nuclear staining remains as long as DNA repair activity is detected in the cells. By extracting the UV-irradiated quiescent cells with Triton X-100 and fixing with formaldehyde, it was possible to demonstrate by indirect immunofluorescence rapid changes in the cyclin/PCNA population after irradiation, a small proportion (5-10%) of which is tightly associated to the nucleus as determined by high salt extraction. By incubating at low temperature and depleting the ATP pools of the cells before UV irradiation, we have demonstrated that the changes in cyclin/PCNA distribution observed involve at least two different nuclear associations.

scholarly journals p53-Mediated Regulation of Proliferating Cell Nuclear Antigen Expression in Cells Exposed to Ionizing Radiation

1999 ◽  
Vol 19 (1) ◽  
pp. 12-20 ◽  
Author(s):  
Jin Xu ◽  
Gilbert F. Morris
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Ionizing Radiation ◽  
Proliferating Cell Nuclear Antigen ◽  
Cellular Response ◽  
Nuclear Antigen ◽  
Dominant Negative Mutant ◽  
Mrna Levels ◽  
Mobility Shift ◽  
Proliferating Cell

ABSTRACT The proliferating cell nuclear antigen (PCNA) is a highly conserved cellular protein that functions both in DNA replication and in DNA repair. Exposure of a rat embryo fibroblast cell line (CREF cells) to γ radiation induced simultaneous expression of PCNA with the p53 tumor suppressor protein and the cyclin-dependent kinase inhibitor p21WAF1/Cip1. PCNA mRNA levels transiently increased in serum-starved cells exposed to ionizing radiation, an observation suggesting that the radiation-associated increase in PCNA expression could be dissociated from cell cycle progression. Irradiation of CREF cells activated a transiently expressed PCNA promoter chloramphenicol acetyltransferase construct through p53 binding sequences via a mechanism blocked by a dominant negative mutant p53. Electrophoretic mobility shift assays with nuclear extracts prepared from irradiated CREF cells produced four p53-specific DNA-protein complexes with the PCNA p53 binding site. Addition of monoclonal antibody PAb421 (p53-specific) or AC238 (specific to the transcriptional coactivator p300/CREB binding protein) to the mobility shift assay distinguished different forms of p53 that changed in relative abundance with time after irradiation. These findings suggest a complex cellular response to DNA damage in which p53 transiently activates expression of PCNA for the purpose of limited DNA repair. In a population of nongrowing cells with diminished PCNA levels, this pathway may be crucial to survival following DNA damage.

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