scholarly journals Rapamycin (sirolimus) inhibits proliferating cell nuclear antigen expression and blocks cell cycle in the G1 phase in human keratinocyte stem cells.

1997 ◽  
Vol 99 (9) ◽  
pp. 2094-2099 ◽  
Author(s):  
A F Javier ◽  
Z Bata-Csorgo ◽  
C N Ellis ◽  
S Kang ◽  
J J Voorhees ◽  
...  
Biochemistry ◽  
1989 ◽  
Vol 28 (7) ◽  
pp. 2967-2974 ◽  
Author(s):  
Yin Chang Liu ◽  
Robert L. Marraccino ◽  
Peter C. Keng ◽  
Robert A. Bambara ◽  
Edith M. Lord ◽  
...  

2017 ◽  
Vol 56 (1) ◽  
Author(s):  
Nazul Becerril ◽  
Miguel Ángel Martínez ◽  
Elpidio García ◽  
Jorge Manuel Vázquez Ramos

Using the technique of Chromatin Immunoprecipitation, we have detected the formation of complexes between the homotrimer protein ring Proliferating Cell Nuclear Antigen, PCNA, and two fundamental regulators of the cell cycle, CdkA and Cyclin D4;2 along germination of maize seeds. This finding suggests the way PCNA participates in the control of the G1 phase, by allowing cyclin-kinase complexes to find and phosphorylate protein targets. Incidentally, PCNA may form a structure of a dimer of trimer when bound to the chromatin.


1993 ◽  
Vol 105 (1) ◽  
pp. 69-80 ◽  
Author(s):  
M. Baptist ◽  
J.E. Dumont ◽  
P.P. Roger

In this study, experimental conditions are described that allowed us to follow the fate of the DNA polymerase delta-associated proliferating cell nuclear antigen (PCNA), by immunolabeling during the overall cell cycle. Differences in subcellular localization or the presence of PCNA allowed us to identify each phase of the cell cycle. Using these cell cycle markers in dog thyroid epithelial cells in primary culture, we found unexpected differences in cell cycle kinetics, in response to stimulations through cAMP-dependent and cAMP-independent pathways. These provide a new dimension to the view that the two pathways are largely separate, but co-operate on DNA synthesis initiation. More precisely, thyrotropin (TSH), acting via cAMP, exerts a potent triggering effect on DNA synthesis, associated with a precocious induction of PCNA appearance. This constitutes the major influence of TSH (cAMP) in determining cell cycle progression, which is only partly moderated by TSH-dependent lengthening of S- and G2-phases.


Placenta ◽  
2007 ◽  
Vol 28 (8-9) ◽  
pp. 803-811 ◽  
Author(s):  
L. Šerman ◽  
M. Vlahović ◽  
M. Šijan ◽  
F. Bulić-Jakuš ◽  
A. Šerman ◽  
...  

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.


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