Host Cell Reactivation in Strains of E. coli lacking DNA Polymerase Activity in vitro

1971 ◽  
Vol 229 (3) ◽  
pp. 82-84 ◽  
Author(s):  
ALBRECHT KLEIN ◽  
UTA NIEBCH
Keyword(s):  
Host Cell ◽  
Dna Polymerase ◽  
Polymerase Activity ◽  
E Coli ◽  
Cell Reactivation ◽  
Host Cell Reactivation

scholarly journals Exploring new potential role of DDB2 by host cell reactivation assay in human tumorigenic cells

BMC Cancer ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Elisabetta Bassi ◽  
Paola Perucca ◽  
Isabella Guardamagna ◽  
Ennio Prosperi ◽  
Lucia A. Stivala ◽  
...  
Keyword(s):  
Dna Repair ◽  
Host Cell ◽  
Human Cells ◽  
Mutant Form ◽  
Cell Reactivation ◽  
Cellular Environment ◽  
Dna Plasmid ◽  
Host Cell Reactivation ◽  
Damaged Dna

Abstract Background The Host Cell Reactivation assay (HCR) allows studying the DNA repair capability in different types of human cells. This assay was carried out to assess the ability in removing UV-lesions from DNA, thus verifying NER efficiency. Previously we have shown that DDB2, a protein involved in the Global Genome Repair, interacts directly with PCNA and, in human cells, the loss of this interaction affects DNA repair machinery. In addition, a mutant form unable to interact with PCNA (DDB2PCNA-), has shown a reduced ability to interact with a UV-damaged DNA plasmid in vitro. Methods In this work, we have investigated whether DDB2 protein may influence the repair of a UV-damaged DNA plasmid into the cellular environment by applying the HCR method. To this end, human kidney 293 stable clones, expressing DDB2Wt or DDB2PCNA-, were co-transfected with pmRFP-N2 and UV-irradiated pEGFP-reported plasmids. Moreover, the co-localization between DDB2 proteins and different NER factors recruited at DNA damaged sites was analysed by immunofluorescence and confocal microscopy. Results The results have shown that DDB2Wt recognize and repair the UV-induced lesions in plasmidic DNA transfected in the cells, whereas a delay in these processes were observed in the presence of DDB2PCNA-, as also confirmed by the different extent of co-localization of DDB2Wt and some NER proteins (such as XPG), vs the DDB2 mutant form. Conclusion The HCR confirms itself as a very helpful approach to assess in the cellular context the effect of expressing mutant vs Wt NER proteins on the DNA damage response. Loss of interaction of DDB2 and PCNA affects negatively DNA repair efficiency.

scholarly journals Defining the function of xeroderma pigmentosum group F protein in psoralen interstrand cross-link-mediated DNA repair and mutagenesis

2004 ◽  
Vol 379 (1) ◽  
pp. 71-78 ◽  
Author(s):  
Zhiwen CHEN ◽  
Xiaoxin Susan XU ◽  
Jason HARRISON ◽  
Gan WANG
Keyword(s):  
Dna Repair ◽  
Host Cell ◽  
Xeroderma Pigmentosum ◽  
Normal Fibroblast ◽  
Fibroblast Cells ◽  
Cross Link ◽  
Cell Reactivation ◽  
Xeroderma Pigmentosum Group F ◽  
Host Cell Reactivation

Many commonly used drugs, such as psoralen and cisplatin, can generate a very unique type of DNA damage, namely ICL (interstrand cross-link). An ICL can severely block DNA replication and transcription and cause programmed cell death. The molecular mechanism of repairing the ICL damage has not been well established. We have studied the role of XPF (xeroderma pigmentosum group F) protein in psoralen-induced ICL-mediated DNA repair and mutagenesis. The results obtained from our mutagenesis studies revealed a very similar mutation frequency in both human normal fibroblast cells and XPF cells. The mutation spectra generated in both cells, however, were very different: most of the mutations generated in the normal fibroblast cells were T167→A transversions, whereas most of the mutations generated in the XPF cells were T167→G transversions. When a wild-type XPF gene cDNA was stably transfected into the XPF cells, the T167→A mutations were increased and the T167→G mutations were decreased. We also determined the DNA repair capability of the XPF cells using both the host-cell reactivation and the in vitro DNA repair assays. The results obtained from the host-cell reactivation experiments revealed an effective reactivation of a luciferase reporter gene from the psoralen-damaged plasmid in the XPF cells. The results obtained from the in vitro DNA repair experiments demonstrated that the XPF nuclear extract is normal in introducing dual incisions during the nucleotide excision repair process. These results suggest that the XPF protein has important roles in the psoralen ICL-mediated DNA repair and mutagenesis.

scholarly journals Host Cell Reactivation and Transcriptional Activation of Carboplatin-Modified BRCA1

2014 ◽  
Vol 8 ◽  
pp. BCBCR.S14224 ◽  
Author(s):  
Adisorn Ratanaphan ◽  
Bhutorn Canyuk
Keyword(s):  
Host Cell ◽  
Transcriptional Activation ◽  
Cancer Susceptibility ◽  
Susceptibility Gene ◽  
Brca1 Gene ◽  
Breast Cancer Susceptibility ◽  
Breast Cancer Susceptibility Gene ◽  
Cell Reactivation ◽  
Host Cell Reactivation

The breast cancer susceptibility gene 1 ( BRCA1) has been shown to maintain genomic stability through multiple functions in the regulation of DNA damage repair and transcription. Its translated BRCT (BRCA1 C-terminal domain) acts as a strong transcriptional activator. BRCA1 damaged by carboplatin treatment may lead to a loss of such functions. To address the possibility of the BRCA1 gene as a therapeutic target for carboplatin, we investigated the functional consequences of the 3′-terminal region of human BRCA1 following in vitro platination with carboplatin. A reduction in cellular BRCA1 repair of carboplatin-treated plasmid DNA, using a host cell reactivation assay, was dependent on the platination levels on the reporter gene. The transcriptional transactivation activity of the drug-modified BRCA1, assessed using a one-hybrid GAL4 transcriptional assay, was inversely proportional to the carboplatin doses. The data emphasized the potential of the BRCA1 gene to be a target for carboplatin treatment.

scholarly journals Catalytically inactive T7 DNA polymerase imposes a lethal replication roadblock

2020 ◽  
Vol 295 (28) ◽  
pp. 9542-9550
Author(s):  
Alfredo J. Hernandez ◽  
Seung-Joo Lee ◽  
Seungwoo Chang ◽  
Jaehun A. Lee ◽  
Joseph J. Loparo ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Metal Binding ◽  
Polymerase Activity ◽  
Stable Complex ◽  
Klenow Fragment ◽  
Dna Polymerase I ◽  
E Coli ◽  
Growth System ◽  
Polymerase I

Bacteriophage T7 encodes its own DNA polymerase, the product of gene 5 (gp5). In isolation, gp5 is a DNA polymerase of low processivity. However, gp5 becomes highly processive upon formation of a complex with Escherichia coli thioredoxin, the product of the trxA gene. Expression of a gp5 variant in which aspartate residues in the metal-binding site of the polymerase domain were replaced by alanine is highly toxic to E. coli cells. This toxicity depends on the presence of a functional E. coli trxA allele and T7 RNA polymerase-driven expression but is independent of the exonuclease activity of gp5. In vitro, the purified gp5 variant is devoid of any detectable polymerase activity and inhibited DNA synthesis by the replisomes of E. coli and T7 in the presence of thioredoxin by forming a stable complex with DNA that prevents replication. On the other hand, the highly homologous Klenow fragment of DNA polymerase I containing an engineered gp5 thioredoxin-binding domain did not exhibit toxicity. We conclude that gp5 alleles encoding inactive polymerases, in combination with thioredoxin, could be useful as a shutoff mechanism in the design of a bacterial cell-growth system.

The Mechanism of Replication of Single-Stranded DNA. VI. Requirements for Ribonucleoside Triphosphates and DNA Polymerase III

1973 ◽  
Vol 51 (12) ◽  
pp. 1588-1597 ◽  
Author(s):  
David T. Denhardt ◽  
Makoto Iwaya ◽  
Grant McFadden ◽  
Gerald Schochetman
Keyword(s):  
Dna Polymerase ◽  
Dna Polymerases ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Dna Polymerase Iii ◽  
Single Stranded Dna ◽  
E Coli ◽  
Polymerase Iii

Evidence is presented that in Escherichia coli made permeable to nucleotides by exposure to toluene, the synthesis of a DNA chain complementary to the infecting single-stranded DNA of bacteriophage [Formula: see text] requires ATP as well as the four deoxyribonucleoside triphosphates. This synthesis results in the formation of the parental double-stranded replicative-form (RF) molecule. The ATP is not required simply to prevent degradation of the ribonucleoside or deoxyribonucleoside triphosphates; it can be partially substituted for by other ribonucleoside triphosphates.No single one of the known E. coli DNA polymerases appears to be uniquely responsible in vivo for the formation of the parental RF. Since [Formula: see text] replicates well in strains lacking all, or almost all, of the in-vitro activities of DNA polymerases I and II, neither of these two enzymes would seem essential; and in a temperature-sensitive E. coli mutant (dnaEts) deficient in DNA polmerase-I activity and possessing a temperature-sensitive DNA polymerase III, the viral single-stranded DNA is efficiently incorporated into an RF molecule at the restrictive temperature. In contrast, both RF replication and progeny single-stranded DNA synthesis are dependent upon DNA polymerase III activity.

Synergistic Inhibition of HIV-1 Reverse Transcriptase DNA Polymerase Activity and Virus Replication in Vitro by Combinations of Carboxanilide Nonnucleoside Compounds

Biochemistry ◽  
1995 ◽  
Vol 34 (32) ◽  
pp. 10106-10112 ◽  
Author(s):  
Ronald S. Fletcher ◽  
Dominique Arion ◽  
Gadi Borkow ◽  
Mark A. Wainberg ◽  
Gary I. Dmitrienko ◽  
...  
Keyword(s):  
Reverse Transcriptase ◽  
Dna Polymerase ◽  
Virus Replication ◽  
Polymerase Activity ◽  
Synergistic Inhibition ◽  
Hiv 1
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