Changes in the content of condensed chromatin during the cell cycle in antheridial filaments ofChara vulgaris L. as related to DNA and RNA synthesis,3H actinomycin D binding and RNA polymerase activity

PROTOPLASMA ◽  
1979 ◽  
Vol 98 (4) ◽  
pp. 363-367 ◽  
Author(s):  
Maria Kwiatkowska ◽  
J. Maszewski
1973 ◽  
Vol 57 (2) ◽  
pp. 538-550 ◽  
Author(s):  
R. Sederoff ◽  
R. Clynes ◽  
M. Poncz ◽  
S. Hachtel

Cytological preparations of Drosophila polytene chromosomes serve as templates for RNA synthesis carried out by exogenous RNA polymerase (Escherichia coli). Incorporation of labeled ribonucleoside triphosphates into RNA may be observed directly by autoradiography. Because of the effects of rifampicin, actinomycin D, ribonuclease, high salt, and the requirement for all four nucleoside triphosphates, we conclude that the labeling observed over chromosomes is due to DNA-dependent RNA polymerase activity. Using this method, one can observe RNA synthesis in vitro on specific chromosome regions due to the activity of exogenous RNA polymerase. We find that much of the RNA synthesis in this system occurs on DNA sequences which appear to be in a nondenatured state.


1977 ◽  
Vol 74 (3) ◽  
pp. 698-706 ◽  
Author(s):  
C D Fuster ◽  
D Farrell ◽  
F A Stern ◽  
N B Hecht

Washed mature spermatozoa from bulls incorporate ribonucleoside triphosphates into RNA using an endogenous template. Maximum incorporation was observed at 31 degrees C in the presence of MgCl2, all four ribonucleoside triphosphates, beta-mercaptoethanol, and glycine sodium hydroxide buffer at pH 9.0. The amount of synthesis was linearly dependent upon the concentration of spermatozoa and continued for at least 4 h. Digestion studies revealed the RNA to be present in a protected (intracellular?) location in the spermatozoa. The RNA synthesis was inhibited by ethidium bromide, rifampicin, acriflavine, actinomycin D, and caffeine, but not by alpha-amanitine or rifamycin SV. Fractionation of the spermatozoa by sonication and separation of the heads and tails by centrifugation through a discontinuous gradient revealed that more than half of the total RNA polymerase activity was associated with the tail fraction.


2010 ◽  
Vol 31 (7) ◽  
pp. 2107-2109 ◽  
Author(s):  
Bok-Hui Lee ◽  
Hyun-Jung Seo ◽  
So-Hyun Kim ◽  
Woong Jung ◽  
Dong-Woon Kim ◽  
...  

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.


1979 ◽  
Vol 34 (3) ◽  
pp. 203-213 ◽  
Author(s):  
F. E. Randall ◽  
D. E. S. Truman ◽  
R. M. Clayton

SUMMARYThe genetically unrelated chick strains Hy-1 and Hy-2, which have been strongly selected for growth rate, both exhibit hyperplasia of the lens epithelium. These two strains and a control strain N, not selected for growth rate, were compared with respect to incorporation of 3H-thymidine and 14C-uridine by freshly excised lenses in culture at different times throughout a 24-h period. The levels of incorporation of label into the lens cells were found to vary according to the time of day. The pattern of diurnal variation in both thymidine and uridine incorporation was found to be strain specific. Hy-1 and Hy-2 showed a greater degree of synchrony than did normal (N) lenses, and the frequency of the peaks of incorporation was also higher. Autoradiography confirmed that only lens epithelium incorporates thymidine during culture and that the number of labelled nuclei depends on the time of day when the lenses were explanted. These data point to genetic control of the cell cycle.


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