scholarly journals Effects of α-amanitinin vivoon RNA polymerase activity of cultured chick embryo fibroblast cell nuclei: Resistance of ribosomal RNA synthesis to the drug

FEBS Letters ◽  
1973 ◽  
Vol 32 (1) ◽  
pp. 95-99 ◽  
Author(s):  
N.D. Hastie ◽  
B.W.J. Mahy
2010 ◽  
Vol 31 (7) ◽  
pp. 2107-2109 ◽  
Author(s):  
Bok-Hui Lee ◽  
Hyun-Jung Seo ◽  
So-Hyun Kim ◽  
Woong Jung ◽  
Dong-Woon Kim ◽  
...  

1993 ◽  
Vol 116 (1) ◽  
pp. 820-822
Author(s):  
Ya. Kh. Turakulov ◽  
S. N. Dalimova ◽  
I. R. Kamalieva ◽  
G. D. Umarova ◽  
B. A. Atakhanova

1977 ◽  
Vol 26 (1) ◽  
pp. 267-279
Author(s):  
K.E. Davies ◽  
I.O. Walker

Methods for isolating nuclei, nucleoli and chromatin from Physarum polycephalum which retain high levels of endogenous RNA polymerase activity are described. Under carefully controlled conditions with respect to mono- and divalent cation concentrations RNA synthesis in nuclei displayed linear kinetics for at least 30 min and the RNA products had a similar size distribution to nuclear RNA synthesis observed in vivo. Chromatin showed 60% of the nuclear transcriptional activity but no conditions were found where faithful transcription of the template occurred. Isolated nucleoli were 5-fold more active than nuclei and the endogenous RNA polymerase activity was insensitive to alpha-amanitin. Under carefully controlled conditions, the nucleoli appeared to support the accurate transcription, re-initiation and processing of rRNA chains in vitro.


1982 ◽  
Vol 201 (1) ◽  
pp. 145-151 ◽  
Author(s):  
J W Dillwith ◽  
R A Lewis

Captan (N-trichloromethylthiocyclohex-4-ene-1,2-dicarboximide) was shown to inhibit RNA synthesis in vitro catalysed by Escherichia coli RNA polymerase. Incorporation of [gamma-32P]ATP and [gamma-32P]GTP was inhibited by captan to the same extent as overall RNA synthesis. The ratio of [3H]UTP incorporation to that of [gamma-32P]ATP or of [gamma-32P]GTP in control and captan-treated samples indicated that initiation was inhibited, but the length of RNA chains being synthesized was not altered by captan treatment. Limited-substrate assays in which re-initiation of RNA chains did not occur also showed that captan had no effect on the elongation reaction. Studies which measured the interaction of RNA polymerase with template DNA revealed that the binding of enzyme to DNA was inhibited by captan. Glycerol-gradient sedimentation of the captan-treated RNA polymerase indicated that the inhibition of the enzyme was irreversible and did not result in dissociation of its subunits. These data are consistent with a mechanism in which RNA polymerase activity was irreversibly altered by captan, resulting in an inability of the enzyme to bind to the template. This interaction was probably at the DNA-binding site on the polymerase and did not involve reaction of captan with the DNA template.


1983 ◽  
Vol 61 (4) ◽  
pp. 341-348 ◽  
Author(s):  
James D. McCully ◽  
Paul B. Taylor ◽  
Nancy L. Morrison

The effect of normal growth (hypertrophy) on myocardial nuclear activity was investigated using male Wistar rats at 21, 50, and 100 days of age. Cardiac mass increased sevenfold during this age range. The concentration of RNA (mg∙g−1) was the highest at 21 days and decreased 48% by 50 days of age and 68% after 100 days of development. RNA synthesis, corrected for alterations in the specific activity of the cytoplasmic nucleotide pool, was the highest at 21 days of age. After 50 days of growth, uridine incorporation was decreased fivefold. With continual growth (100 days), RNA synthesis was still reduced compared with the 21-day animals. RNA polymerase activity in myocyte nuclei showed little change in activity from 21 to 100 days of age. However, in the nonmyocyte fraction, RNA polymerase decreased threefold after 50 days of development. Collectively, these data suggest that the large decrease in myocardial RNA synthesis cannot be accounted for by a change in nuclear RNA polymerase activity and that an alteration in chromatin template capacity may be involved during this form of cardiac growth.


1979 ◽  
Vol 184 (3) ◽  
pp. 669-674 ◽  
Author(s):  
R Bolla ◽  
W D Denckla

Changes in RNA synthesis in liver nuclei were observed at different ages and after hypophysectomy and hormone replacement in female Sprague-Dawley rats. As determined by the incorporation of [3H]UMP into an acid-insoluble product, RNA synthesis decreased by about 75% in intact rats from 6 months to 24 months of age. This decline with age was not observed in liver nuclei from 24-month-old rats that had been hypophysectomized at 12 months and maintained on a minimal hormone-replacement therapy. Thyroid hormones and somatotropin (growth hormone) had an additive effect on RNA synthesis in liver nuclei from these hypophysectomized rats. The same hormones had no significant effect on intact, age-matched rats. With advancing age, nuclei of intact rats had an increase in the pool of free RNA polymerase and an apparent decrease in the enzyme activity bound to nuclear chromatin. There was no change in total enzyme with age. In hypophysectomized, hormone-treated rats, free RNA polymerase activity decreased and chromatin-bound activity increased. There was no difference in total nuclear RNA polymerase activity between operated or intact rats. However, the ratio of the bound to the free activity was different. These results suggest that the ability of RNA polymerase to bind to chromatin may be involved in the age-related decrease in liver nuclear RNA synthesis of intact rats.


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