scholarly journals TRIM28 functions as the SUMO E3 ligase for PCNA in prevention of transcription induced DNA breaks

2020 ◽  
Vol 117 (38) ◽  
pp. 23588-23596
Author(s):  
Min Li ◽  
Xiaohua Xu ◽  
Chou-Wei Chang ◽  
Yilun Liu

In human cells, the DNA replication factor proliferating cell nuclear antigen (PCNA) can be conjugated to either the small ubiquitinlike modifier SUMO1 or SUMO2, but only SUMO2-conjugated PCNA is induced by transcription to facilitate resolution of transcription–replication conflict (TRC). To date, the SUMO E3 ligase that provides substrate specificity for SUMO2-PCNA conjugation in response to TRC remains unknown. Using a proteomic approach, we identified TRIM28 as the E3 ligase that catalyzes SUMO2-PCNA conjugation. In vitro, TRIM28, together with the RNA polymerase II (RNAPII)-interacting protein RECQ5, promotes SUMO2-PCNA conjugation but inhibits SUMO1-PCNA formation. This activity requires a PCNA-interacting protein (PIP) motif located within the bromodomain of TRIM28. In cells, TRIM28 interaction with PCNA on human chromatin is dependent on both transcription and RECQ5, and SUMO2-PCNA level correlates with TRIM28 expression. As a consequence, TRIM28 depletion led to RNAPII accumulation at TRC sites, and expression of a TRIM28 PIP mutant failed to suppress TRC-induced DNA breaks.

1994 ◽  
Vol 4 (8) ◽  
pp. 1588-1597
Author(s):  
R A Zager ◽  
S M Fuerstenberg ◽  
P H Baehr ◽  
D Myerson ◽  
B Torok-Storb

Xanthine oxidase (XO) activity and hydroxyl radical (.OH) formation are widely proposed mediators of renal reperfusion injury, potentially altering the severity of, and recovery from, postischemic acute renal failure. The goal of this study was to ascertain whether combination XO inhibitor (oxypurinol) and .OH scavenger (Na benzoate) therapy, given at the time of renal ischemia, alters the extent of: (1) tubular necrosis and filtration failure; (2) DNA fragmentation/apoptosis (assessed in situ by terminal deoxynucleotidyl transferase reactivity); (3) early tubular regenerative responses (proliferating cell nuclear antigen expression; (3H)thymidine incorporation); and (4) the rate and/or degree of functional and morphologic repair. The effects of XO inhibition, .OH scavengers, and "catalytic" iron (FeSO4) on human proximal tubular cell proliferation in vitro were also assessed with a newly established cell line (HK-2). Male Sprague-Dawley rats were subjected to 35 min of bilateral renal arterial occlusion with or without oxypurinol/benzoate therapy. These agents did not alter the extent of tubular necrosis or filtration failure, proliferating cell nuclear antigen expression or thymidine incorporation, or the rate/extent of renal functional/morphologic repair. DNA fragmentation did not precede tubular necrosis, and it was unaffected by antioxidant therapy. By 5 days postischemia, both treatment groups demonstrated regenerating epithelial fronds that protruded into the lumina. These structures contained terminal deoxynucleotidyl transferase-reactive, but morphologically intact, cells, suggesting the presence of apoptosis. Oxypurinol and .OH scavengers (benzoate; dimethylthiourea) suppressed in vitro tubular cell proliferation; conversely, catalytic Fe had a growth-stimulatory effect. These results suggest that: (1) XO inhibition/.OH scavenger therapy has no discernible net effect on postischemic acute renal failure; (2) DNA fragmentation does not precede tubular necrosis, suggesting that it is not a primary mediator of ischemic cell death; and (3) antioxidants can be antiproliferative for human tubular cells, possibly mitigating their potential beneficial effects.


1989 ◽  
Vol 9 (1) ◽  
pp. 57-66
Author(s):  
M Zuber ◽  
E M Tan ◽  
M Ryoji

Proliferating cell nuclear antigen (PCNA) (also called cyclin) is known to stimulate the activity of DNA polymerase delta but not the other DNA polymerases in vitro. We injected a human autoimmune antibody against PCNA into unfertilized eggs of Xenopus laevis and examined the effects of this antibody on the replication of injected plasmid DNA as well as egg chromosomes. The anti-PCNA antibody inhibited plasmid replication by up to 67%, demonstrating that PCNA is involved in plasmid replication in living cells. This result further implies that DNA polymerase delta is necessary for plasmid replication in vivo. Anti-PCNA antibody alone did not block plasmid replication completely, but the residual replication was abolished by coinjection of a monoclonal antibody against DNA polymerase alpha. Anti-DNA polymerase alpha alone inhibited plasmid replication by 63%. Thus, DNA polymerase alpha is also required for plasmid replication in this system. In similar studies on the replication of egg chromosomes, the inhibition by anti-PCNA antibody was only 30%, while anti-DNA polymerase alpha antibody blocked 73% of replication. We concluded that the replication machineries of chromosomes and plasmid differ in their relative content of DNA polymerase delta. In addition, we obtained evidence through the use of phenylbutyl deoxyguanosine, an inhibitor of DNA polymerase alpha, that the structure of DNA polymerase alpha holoenzyme for chromosome replication is significantly different from that for plasmid replication.


2010 ◽  
Vol 207 (12) ◽  
pp. 2631-2645 ◽  
Author(s):  
Véronique Witko-Sarsat ◽  
Julie Mocek ◽  
Dikra Bouayad ◽  
Nicola Tamassia ◽  
Jean-Antoine Ribeil ◽  
...  

Neutrophil apoptosis is a highly regulated process essential for inflammation resolution, the molecular mechanisms of which are only partially elucidated. In this study, we describe a survival pathway controlled by proliferating cell nuclear antigen (PCNA), a nuclear factor involved in DNA replication and repairing of proliferating cells. We show that mature neutrophils, despite their inability to proliferate, express high levels of PCNA exclusively in their cytosol and constitutively associated with procaspases, presumably to prevent their activation. Notably, cytosolic PCNA abundance decreased during apoptosis, and increased during in vitro and in vivo exposure to the survival factor granulocyte colony-stimulating factor (G-CSF). Peptides derived from the cyclin-dependent kinase inhibitor p21, which compete with procaspases to bind PCNA, triggered neutrophil apoptosis thus demonstrating that specific modification of PCNA protein interactions affects neutrophil survival. Furthermore, PCNA overexpression rendered neutrophil-differentiated PLB985 myeloid cells significantly more resistant to TNF-related apoptosis-inducing ligand– or gliotoxin-induced apoptosis. Conversely, a decrease in PCNA expression after PCNA small interfering RNA transfection sensitized these cells to apoptosis. Finally, a mutation in the PCNA interdomain-connecting loop, the binding site for many partners, significantly decreased the PCNA-mediated antiapoptotic effect. These results identify PCNA as a regulator of neutrophil lifespan, thereby highlighting a novel target to potentially modulate pathological inflammation.


1995 ◽  
Vol 43 (12) ◽  
pp. 1217-1221 ◽  
Author(s):  
Y Morimoto ◽  
K Saga

Morphological observations of sweat glands showed degenerated debris of secretory cells in the secretory lumen in both apocrine and eccrine sweat glands. This suggested that dead secretory cells of human eccrine and apocrine sweat glands were released into the lumen and replaced by other cells. However, we did not know which type of cells replaced lost secretory cells. Therefore, we studied the proliferating cells in human eccrine and apocrine sweat glands by labeling S-phase cells in vitro with 5-bromo-2'-deoxyuridine (BrdUrd) and by immunostaining proliferation-associated proliferating cell nuclear antigen (PCNA) with anti-PCNA monoclonal antibody. BrdUrd and anti-PCNA antibody labeled a few secretory cells in eccrine and apocrine sweat glands, but neither method labeled myoepithelial cells. Luminal and peripheral cells of the eccrine and apocrine coiled duct were labeled with both BrdUrd and PCNA. However, we could not find any highly proliferative germinative cells in coiled ducts. Our results suggest that lost secretory cells could be replaced by proliferation of secretory cells themselves rather than by proliferation of myoepithelial cells or duct cells.


1993 ◽  
Vol 13 (5) ◽  
pp. 2882-2890 ◽  
Author(s):  
D Denis ◽  
P A Bullock

Studies of simian virus 40 (SV40) DNA replication in vitro have identified a small (approximately 30-nucleotide) RNA-DNA hybrid species termed primer-DNA. Initial experiments indicated that T antigen and the polymerase alpha-primase complex are required to form primer-DNA. Proliferating cell nuclear antigen, and presumably proliferating cell nuclear antigen-dependent polymerases, is not needed to form this species. Herein, we present an investigation of the stages at which primer-DNA functions during SV40 DNA replication in vitro. Hybridization studies indicate that primer-DNA is initially formed in the origin region and is subsequently synthesized in regions distal to the origin. At all time points, primer-DNA is synthesized from templates for lagging-strand DNA replication. These studies indicate that primer-DNA functions during both initiation and elongation stages of SV40 DNA synthesis. Results of additional experiments suggesting a precursor-product relationship between formation of primer-DNA and Okazaki fragments are presented.


2007 ◽  
Vol 189 (15) ◽  
pp. 5652-5657 ◽  
Author(s):  
Kazuo Tori ◽  
Megumi Kimizu ◽  
Sonoko Ishino ◽  
Yoshizumi Ishino

ABSTRACT Proliferating cell nuclear antigen (PCNA) is the sliding clamp that is essential for the high processivity of DNA synthesis during DNA replication. Pyrococcus furiosus, a hyperthermophilic archaeon, has at least two DNA polymerases, polymerase BI (PolBI) and PolD. Both of the two DNA polymerases interact with the archaeal P. furiosus PCNA (PfuPCNA) and perform processive DNA synthesis in vitro. This phenomenon, in addition to the fact that both enzymes display 3′-5′ exonuclease activity, suggests that both DNA polymerases work in replication fork progression. We demonstrated here that both PolBI and PolD functionally interact with PfuPCNA at their C-terminal PIP boxes. The mutant PolBI and PolD enzymes lacking the PIP-box sequence do not respond to the PfuPCNA at all in an in vitro primer extension reaction. This is the first experimental evidence that the PIP-box motif, located at the C termini of the archaeal DNA polymerases, is actually critical for PCNA binding to form a processive DNA-synthesizing complex.


1994 ◽  
Vol 6 (4) ◽  
pp. 453-457 ◽  
Author(s):  
Alain Pierre Théon ◽  
Loretta Metzger ◽  
Stephen Griffey

Cell proliferation in canine, feline, and equine tumors was evaluated using immunohistochemical detection of in vitro 5–bromodeoxyuridine (BrdU) incorporation, proliferating cell nuclear antigen (PCNA), and interchromatin-associated antigen (p105). Ten tumors in each species were analyzed. The tumor proliferative fraction (PF) was defined as the percentage of labeled nuclei for 5,000 tumor nuclei counted. Immunoreactivity was observed with all techniques in all species. A good correlation was observed between the proliferative fractions measured with the BrdU (PFBrdU) and PCNA (PFPCNA) techniques ( rs = 0.523, P = 0.0026). There was no correlation between the PFs measured with the BrdU (PFBrdU) and p105 (PFP105) techniques. Using the median values obtained from the different approaches as cutoff points to define slowly and rapidly proliferating tumors, there was an 80% agreement ( P = 0.009) between PFBrdU and PFPCNA and no agreement between PFBrdU and PFP105 The results of this study indicate that both BrdU and PCNA labeling methods can be used reliably for identifying proliferating cells in animal tumors. In addition, PCNA could be used to replace the BrdU method to assess tumor proliferative fraction because it does not require pretreatment of tissues.


1989 ◽  
Vol 9 (2) ◽  
pp. 609-619 ◽  
Author(s):  
T Tsurimoto ◽  
B Stillman

Cell extracts (S100) derived from human 293 cells were separated into five fractions by phosphocellulose chromatography and monitored for their ability to support simian virus 40 (SV40) DNA replication in vitro in the presence of purified SV40 T antigen. Three fractions, designated I, IIA, and IIC, were essential. Fraction IIC contained the known replication factors topoisomerases I and II, but in addition contained a novel replication factor called RF-C. The RF-C activity, assayed in the presence of I, IIA, and excess amounts of purified topoisomerases, was detected in both cytosol and nuclear fractions, but was more abundant in the latter fraction. RF-C was purified from the 293 cell nuclear fraction to near homogeneity by conventional column chromatography. The reconstituted reaction mix containing purified RF-C could replicate SV40 origin-containing plasmid DNA more efficiently than could the S100 extract, and the products were predominantly completely replicated, monomer molecules. Interestingly, in the absence of RF-C, early replicative intermediates accumulated and subsequent elongation was aberrant. Hybridization studies with strand-specific, single-stranded M13-SV40 DNAs showed that in the absence of RF-C, abnormal DNA synthesis occurred preferentially on the lagging strand, and leading-strand replication was inefficient. These products closely resembled those previously observed for SV40 DNA replication in vitro in the absence of proliferating-cell nuclear antigen. These results suggest that an elongation complex containing RF-C and proliferating-cell nuclear antigen is assembled after formation of the first nascent strands at the replication origin. Subsequent synthesis of leading and lagging strands at a eucaryotic DNA replication fork can be distinguished by different requirements for multiple replication components, but we suggest that even though the two polymerases function asymmetrically, they normally progress coordinately.


1990 ◽  
Vol 172 (2) ◽  
pp. 419-429 ◽  
Author(s):  
J P Huff ◽  
G Roos ◽  
C L Peebles ◽  
R Houghten ◽  
K F Sullivan ◽  
...  

A cDNA clone encoding full-length human proliferating cell nuclear antigen (PCNA) was used to generate a panel of in vitro translated labeled protein products with COOH-terminal deletions and to construct a set of fusion proteins with COOH- and NH2-terminal deletions. A rabbit antiserum raised against an NH2-terminal peptide, a well-characterized murine monoclonal antibody (mAb), and 14 human lupus sera with autoantibody to PCNA were analyzed for their reactivity with the constructs using both immunoprecipitation and immunoblotting techniques. The rabbit antiserum reacted in immunoprecipitation and immunoblotting with constructs containing the appropriate NH2-terminal sequence and mAb reacted with a sequence from the midregion of PCNA. These experimentally induced antibodies also reacted with 15-mer synthetic peptides in enzyme-linked immunosorbent assay (ELISA). In contrast, none of the lupus sera reacted with synthetic peptides in ELISA. 9 of the 14 lupus sera also failed to react in Western immunoblotting with any recombinant fusion protein, although they all immunoprecipitated in vitro translated full-length protein. Four of the nine had variable patterns of immunoprecipitation with shorter constructs. The remaining five lupus sera were able to immunoprecipitate translation products as well as Western blot recombinant fusion proteins. From analysis of the patterns of reactivity of human lupus sera, it was deduced that the apparent heterogeneity of human autoantibodies to PCNA could be explained by immune response to highly conformational epitopes. These observations demonstrate that there might be special features in "native" epitopes of intranuclear antigens that are recognized by autoantibodies, and that these special features of native epitopes might not be present in prepared antigen used for experimental immunization. These features may be related to protein folding or to association of the antigen with other intranuclear proteins or nucleic acids, as might occur with antigens that are components of subcellular particles.


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