scholarly journals Wild-type human p53 transactivates the human proliferating cell nuclear antigen promoter.

1995 ◽  
Vol 15 (12) ◽  
pp. 6785-6793 ◽  
Author(s):  
C V Shivakumar ◽  
D R Brown ◽  
S Deb ◽  
S P Deb
Keyword(s):  
Binding Site ◽  
Proliferating Cell Nuclear Antigen ◽  
P53 Protein ◽  
Cellular Growth ◽  
Nuclear Antigen ◽  
Wild Type ◽  
P53 Response ◽  
Low Levels ◽  
Wild Type P53 ◽  
Proliferating Cell

The wild-type p53 protein is a transcriptional activator implicated in the control of cellular growth-related gene expression. Here, using a number of different cell lines and transient-transfection-transcription assays, we demonstrate that at low levels, wild-type p53 transactivates the human proliferating cell nuclear antigen (PCNA) promoter. When expressed at a similar level, the tumor-derived p53 mutants did not transactivate the PCNA promoter. We identified a p53-binding site on the human PCNA promoter with which p53 interacts sequence specifically. When placed on a heterologous synthetic promoter, the binding site functions as a wild-type p53 response element in either orientation. Deletion of the p53-binding site renders the PCNA promoter p53 nonresponsive, showing that wild-type p53 transactivates the PCNA promoter by binding to the site. At a higher concentration, wild-type p53 inhibits the PCNA promoter but p53 mutants activate. Transactivation by p53 mutants does not require the p53-binding site. These observations suggest that moderate elevation of the cellular wild-type p53 level induces PCNA production to help in DNA repair.

scholarly journals Mutant DNA polymerase δ from thermosensitive Schizosaccharomyces pombe strains display reduced stimulation by proliferating cell nuclear antigen

1998 ◽  
Vol 335 (3) ◽  
pp. 581-588 ◽  
Author(s):  
Mylène PERDERISET ◽  
Giovanni MAGA ◽  
Karine PIARD ◽  
Stefania FRANCESCONI ◽  
Isabelle TRATNER ◽  
...  
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Dna Polymerase ◽  
Proliferating Cell Nuclear Antigen ◽  
Catalytic Subunit ◽  
Nuclear Antigen ◽  
Wild Type ◽  
Low Levels ◽  
Proliferating Cell ◽  
Stimulation Of

We have isolated and characterized DNA polymerase δ (pol δ) from two thermosensitive Schizosaccharomyces pombe strains, polδts1 and polδts3, mutated in two different evolutionarily conserved domains of the catalytic subunit. At the restrictive temperature of 37 °C polδts1 and polδts3 mutant strains arrest growth in the S phase of the cell cycle. We show that at low levels of primer ends, in vitro stimulation by proliferating cell nuclear antigen (PCNA) of mutant enzymes is lower than stimulation of wild-type pol δ. Affinity for primer (3´-OH) ends and processivity of mutant enzymes do not appear different from wild-type pol δ. In contrast, Vmax values are lower than the wild-type value. The major in vitro defect appears to be decreased stimulation of mutant enzymes by PCNA, resulting in reduced velocity of DNA synthesis. In addition, ts1 pol δ is not stimulated by low PCNA concentration at 37 °C, although low concentrations stimulate activity at 25 °C, suggesting that this thermolability at low levels of primer ends could be its critical defect in vivo. Thus, both ts1 and ts3 pol δ mutations are located in regions of the catalytic subunit that seem necessary, directly or indirectly, for its efficient interaction with PCNA.

scholarly journals Characterization of the Proliferating Cell Nuclear Antigen of Leishmania donovani Clinical Isolates and Its Association with Antimony Resistance

2014 ◽  
Vol 58 (6) ◽  
pp. 2997-3007 ◽  
Author(s):  
Rati Tandon ◽  
Sharat Chandra ◽  
Rajendra Kumar Baharia ◽  
Sanchita Das ◽  
Pragya Misra ◽  
...  
Keyword(s):  
Clinical Isolate ◽  
Proliferating Cell Nuclear Antigen ◽  
Leishmania Donovani ◽  
Clinical Isolates ◽  
Resistant Isolate ◽  
Nuclear Antigen ◽  
Wild Type ◽  
Content Type ◽  
Sensitive Isolate ◽  
Proliferating Cell

ABSTRACTPreviously, through a proteomic analysis, proliferating cell nuclear antigen (PCNA) was found to be overexpressed in the sodium antimony gluconate (SAG)-resistant clinical isolate compared to that in the SAG-sensitive clinical isolate ofLeishmania donovani. The present study was designed to explore the potential role of the PCNA protein in SAG resistance inL. donovani. For this purpose, the protein was cloned, overexpressed, purified, and modeled. Western blot (WB) and real-time PCR (RT-PCR) analyses confirmed that PCNA was overexpressed by ≥3-fold in the log phase, stationary phase, and peanut agglutinin isolated procyclic and metacyclic stages of the promastigote form and by ∼5-fold in the amastigote form of the SAG-resistant isolate compared to that in the SAG-sensitive isolate.L. donovaniPCNA (LdPCNA) was overexpressed as a green fluorescent protein (GFP) fusion protein in a SAG-sensitive clinical isolate ofL. donovani, and modulation of the sensitivities of the transfectants to pentavalent antimonial (SbV) and trivalent antimonial (SbIII) drugs was assessedin vitroagainst promastigotes and intracellular (J774A.1 cell line) amastigotes, respectively. Overexpression of LdPCNA in the SAG-sensitive isolate resulted in an increase in the 50% inhibitory concentrations (IC50) of SbV(from 41.2 ± 0.6 μg/ml to 66.5 ± 3.9 μg/ml) and SbIII(from 24.0 ± 0.3 μg/ml to 43.4 ± 1.8 μg/ml). Moreover, PCNA-overexpressing promastigote transfectants exhibited less DNA fragmentation compared to that of wild-type SAG-sensitive parasites upon SbIIItreatment. In addition, SAG-induced nitric oxide (NO) production was found to be significantly inhibited in the macrophages infected with the transfectants compared with that in wild-type SAG-sensitive parasites. Consequently, we infer that LdPCNA has a significant role in SAG resistance inL. donovaniclinical isolates, which warrants detailed investigations regarding its mechanism.

scholarly journals The mdm-2 oncogene can overcome wild-type p53 suppression of transformed cell growth

1993 ◽  
Vol 13 (1) ◽  
pp. 301-306 ◽  
Author(s):  
C A Finlay
Keyword(s):  
P53 Protein ◽  
Mutant P53 ◽  
Wild Type ◽  
Rat Embryo ◽  
Ras Gene ◽  
Double Minute ◽  
Murine Double Minute ◽  
Low Levels ◽  
Wild Type P53 ◽  
P53 Genes

Expression of a p53-associated protein, Mdm-2 (murine double minute-2), can inhibit p53-mediated transactivation. In this study, overexpression of the Mdm-2 protein was found to result in the immortalization of primary rat embryo fibroblasts (REFs) and, in conjunction with an activated ras gene, in the transformation of REFs. The effect of wild-type p53 on the transforming properties of mdm-2 was determined by transfecting REFs with ras, mdm-2, and normal p53 genes. Transfection with ras plus mdm-2 plus wild-type p53 resulted in a 50% reduction in the number of transformed foci (relative to the level for ras plus mdm-2); however, more than half (9 of 17) of the cell lines derived from these foci expressed low levels of a murine p53 protein with the characteristics of a wild-type p53. These results are in contrast to previous studies which demonstrated that even minimal levels of wild-type p53 are not tolerated in cells transformed by ras plus myc, E1A, or mutant p53. The mdm-2 oncogene can overcome the previously demonstrated growth-suppressive properties of p53.

scholarly journals APIM-Mediated REV3L–PCNA Interaction Important for Error Free TLS Over UV-Induced DNA Lesions in Human Cells

2018 ◽  
Vol 20 (1) ◽  
pp. 100 ◽  
Author(s):  
Synnøve Ræder ◽  
Anala Nepal ◽  
Karine Bjørås ◽  
Mareike Seelinger ◽  
Rønnaug Kolve ◽  
...  
Keyword(s):  
Cell Lines ◽  
Proliferating Cell Nuclear Antigen ◽  
Dna Lesions ◽  
Full Length ◽  
Nuclear Antigen ◽  
Wild Type ◽  
Replication Foci ◽  
Multiple Cell ◽  
Mutation Spectra ◽  
Proliferating Cell

Proliferating cell nuclear antigen (PCNA) is essential for the organization of DNA replication and the bypass of DNA lesions via translesion synthesis (TLS). TLS is mediated by specialized DNA polymerases, which all interact, directly or indirectly, with PCNA. How interactions between the TLS polymerases and PCNA affects TLS specificity and/or coordination is not fully understood. Here we show that the catalytic subunit of the essential mammalian TLS polymerase POLζ, REV3L, contains a functional AlkB homolog 2 PCNA interacting motif, APIM. APIM from REV3L fused to YFP, and full-length REV3L-YFP colocalizes with PCNA in replication foci. Colocalization of REV3L-YFP with PCNA is strongly reduced when an APIM-CFP construct is overexpressed. We also found that overexpression of full-length REV3L with mutated APIM leads to significantly altered mutation frequencies and mutation spectra, when compared to overexpression of full-length REV3L wild-type (WT) protein in multiple cell lines. Altogether, these data suggest that APIM is a functional PCNA-interacting motif in REV3L, and that the APIM-mediated PCNA interaction is important for the function and specificity of POLζ in TLS. Finally, a PCNA-targeting cell-penetrating peptide, containing APIM, reduced the mutation frequencies and changed the mutation spectra in several cell lines, suggesting that efficient TLS requires coordination mediated by interactions with PCNA.

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