Inhibition of de novo RNA synthesis by the insecticidal exotoxin of Bacillus thuringiensis var. gelechiae

1969 ◽  
Vol 34 (6) ◽  
pp. 1786-1791 ◽  
Author(s):  
K. Šebesta ◽  
K. Horská ◽  
J. Vaňková
Keyword(s):  
Bacillus Thuringiensis ◽  
Rna Synthesis ◽  
De Novo

Mechanism for De Novo RNA Synthesis and Initiating Nucleotide Specificity by T7 RNA Polymerase

2007 ◽  
Vol 370 (2) ◽  
pp. 256-268 ◽  
Author(s):  
William P. Kennedy ◽  
Jamila R. Momand ◽  
Y. Whitney Yin
Keyword(s):  
Rna Polymerase ◽  
Rna Synthesis ◽  
De Novo ◽  
T7 Rna Polymerase ◽  
Nucleotide Specificity

scholarly journals Factors affecting de novo RNA synthesis and back-priming by the respiratory syncytial virus polymerase

Virology ◽  
2014 ◽  
Vol 462-463 ◽  
pp. 318-327 ◽  
Author(s):  
Sarah L. Noton ◽  
Waleed Aljabr ◽  
Julian A. Hiscox ◽  
David A. Matthews ◽  
Rachel Fearns
Keyword(s):  
Respiratory Syncytial Virus ◽  
Rna Synthesis ◽  
De Novo ◽  
Factors Affecting ◽  
Syncytial Virus

Glucocorticoid-regulated compartmentalization of cell surface-associated glycoproteins in rat hepatoma cells: evidence for an independent response that requires receptor function and de novo RNA synthesis

1987 ◽  
Vol 7 (4) ◽  
pp. 1508-1517
Author(s):  
O K Haffar ◽  
A K Vallerga ◽  
S A Marenda ◽  
H J Witchel ◽  
G L Firestone
Keyword(s):  
Cell Surface ◽  
Time Course ◽  
Rna Synthesis ◽  
De Novo ◽  
Receptor Occupancy ◽  
Receptor Function ◽  
Intracellular Fraction ◽  
Culture Cells ◽  
Viral Glycoproteins ◽  
Rat Hepatoma

The role of glucocorticoid hormones in the compartmentalization of cell surface-associated mouse mammary tumor virus (MMTV) glycoproteins was examined in M1.54, a cloned line of MMTV-infected rat hepatoma tissue culture cells. The expression of cellular [2-3H]mannose-labeled and cell surface 125I-labeled MMTV glycoproteins was examined throughout a time course of exposure to dexamethasone, a synthetic glucocorticoid. Posttranslational localization of cell surface MMTV glycoproteins required 6 h of exposure to hormone and occurred approximately 4 h after their initial production in an intracellular fraction. This regulated localization to the cell surface correlated with glucocorticoid receptor occupancy and was inhibited by exposure to RU 38486, a powerful antagonist of glucocorticoid-mediated responses. Cell surface immunoprecipitation demonstrated that actinomycin D, an inhibitor of de novo RNA synthesis, prevented regulated expression of cell surface viral glycoproteins, suggesting that newly synthesized cellular components mediate this process. The localization of cell surface MMTV glycoproteins appeared normal in a transcriptional variant (CR1) that produces basal levels of MMTV RNA and glycoprotein precursors in the presence of dexamethasone. Thus, regulated compartmentalization of viral glycoproteins is not an obligate consequence of a critical precursor concentration. Taken together, our results suggest that posttranslational trafficking of cell surface-destined MMTV glycoproteins resulted from an independent glucocorticoid hormone response that required receptor function and de novo RNA synthesis.

scholarly journals De Novo Initiation of RNA Synthesis by the RNA-Dependent RNA Polymerase (NS5B) of Hepatitis C Virus

2000 ◽  
Vol 74 (2) ◽  
pp. 851-863 ◽  
Author(s):  
Guangxiang Luo ◽  
Robert K. Hamatake ◽  
Danielle M. Mathis ◽  
Jason Racela ◽  
Karen L. Rigat ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Rna Polymerase ◽  
Rna Synthesis ◽  
De Novo ◽  
Oligonucleotide Primer ◽  
Transferase Activity ◽  
Rdrp Activity ◽  
Rna Dependent Rna Polymerase ◽  
Hcv Ns5b

ABSTRACT Hepatitis C virus (HCV) NS5B protein possesses an RNA-dependent RNA polymerase (RdRp) activity, a major function responsible for replication of the viral RNA genome. To further characterize the RdRp activity, NS5B proteins were expressed from recombinant baculoviruses, purified to near homogeneity, and examined for their ability to synthesize RNA in vitro. As a result, a highly active NS5B RdRp (1b-42), which contains an 18-amino acid C-terminal truncation resulting from a newly created stop codon, was identified among a number of independent isolates. The RdRp activity of the truncated NS5B is comparable to the activity of the full-length protein and is 20 times higher in the presence of Mn2+ than in the presence of Mg2+. When a 384-nucleotide RNA was used as the template, two major RNA products were synthesized by 1b-42. One is a complementary RNA identical in size to the input RNA template (monomer), while the other is a hairpin dimer RNA synthesized by a “copy-back” mechanism. Substantial evidence derived from several experiments demonstrated that the RNA monomer was synthesized through de novo initiation by NS5B rather than by a terminal transferase activity. Synthesis of the RNA monomer requires all four ribonucleotides. The RNA monomer product was verified to be the result of de novo RNA synthesis, as two expected RNA products were generated from monomer RNA by RNase H digestion. In addition, modification of the RNA template by the addition of the chain terminator cordycepin at the 3′ end did not affect synthesis of the RNA monomer but eliminated synthesis of the self-priming hairpin dimer RNA. Moreover, synthesis of RNA on poly(C) and poly(U) homopolymer templates by 1b-42 NS5B did not require the oligonucleotide primer at high concentrations (≥50 μM) of GTP and ATP, further supporting a de novo initiation mechanism. These findings suggest that HCV NS5B is able to initiate RNA synthesis de novo.

Stimulierung von Kulturen embryonaler Rattenzellen durch Kälberserum, III / Stimulation of Embryonic Rat Cells in Culture by Calf Serum, III

1972 ◽  
Vol 27 (11) ◽  
pp. 1399-1404 ◽  
Author(s):  
Michael Humpel ◽  
Werner Frank
Keyword(s):  
Rna Synthesis ◽  
De Novo ◽  
Calf Serum ◽  
Serum Free Medium ◽  
Free Medium ◽  
Serum Free ◽  
Uridine Uptake ◽  
Insoluble Material ◽  
Turn Over ◽  
Precursor Molecules

Embryonic rat cells which have been stopped in G1-phase of their cell cycle by incubation in serum-free medium can be triggered by the addition of calf serum.Expamination of uridine uptake and RNA synthesis after stimulation gave the following results:1) Uridine uptake into the acid soluble pool is increased within a few minutes.2) 2 hours after the addition of serum cells incorporate twice as much 3H-uridine into the acid insoluble material as do cells in serum-free medium; this is not the result of a higher rate of RNA synthesis but is due to an increased uridine uptake.As demonstrated by isolation of RNA and electrophoresis in polyacrylamide gels a significant de novo synthesis can be detected 4 hours after stimulation. Sedimentation coefficients of these RNA species are between 28S and 18S, and 18S and 4/5S, resp.; they turn over quite rapidly as was demonstrated by chase experiments.3) When cells are grown for 2 hours in medium containing 3H-uridine, little label can be detected in the ribosomal 18S- and 28S-RNA. Radioaktivity in these species is, however, strongly increased after another incubation period of 2 hours in culture medium without 3H-uridine. This indicates that precursor molecules ars synthetized and subsequently degrated into 28S- and 18S-rRNA.

Regulation of the Synthesis of Ribulose-l,5-bisphosphate Carboxylase and Its Subunits in the Flagellate Chlorogonium elongatum. II. Coordinated Synthesis of the Large and Small Subunits

1981 ◽  
Vol 36 (11-12) ◽  
pp. 942-950 ◽  
Author(s):  
Peter Westhoff ◽  
Kurt Zimmermann ◽  
Frank Boege ◽  
Klaus Zetsche
Keyword(s):  
Rna Synthesis ◽  
De Novo ◽  
Fold Increase ◽  
Growth Conditions ◽  
Autotrophic Growth ◽  
De Novo Synthesis ◽  
Bisphosphate Carboxylase ◽  
Unicellular Green Alga ◽  
Protein And Rna Synthesis ◽  
Ribulosebisphosphate Carboxylase

Abstract Transfer of heterotrophically grown cells of the unicellular green alga Chlorogonium elongatum to autotrophic growth conditions causes a 10 -15 fold increase in the amount of the chloroplastic enzyme ribulose-1,5-bisphosphate carboxylase. This increase was found to be due to de novo synthesis. The relative proportions of large and small subunits of the enzyme do not change. Their ratio is close to 3.4, the proportions in weight of the two subunits in the holoenzyme. Continous labelling with [35S]sulfate reveals that the ratios of incorporation into large and small subunits are essentially the same in autotrophic and heterotrophic cells. Pulse-chase experiments show that the subunits are degraded synchronously. The coordinated subunit synthesis cannot be uncoupled using inhibitors of protein and RNA synthesis or high temperature of cultivation of the alga. The results suggests a very tightly coordinated synthesis of the large and small subunits of ribulosebisphosphate carboxylase.

scholarly journals Evidence for the De Novo Synthesis of Erythropoietin in Hypoxic Rats

Blood ◽  
1972 ◽  
Vol 40 (5) ◽  
pp. 662-670 ◽  
Author(s):  
J. C. Schooley ◽  
L. J. Mahlmann
Keyword(s):  
Rna Synthesis ◽  
Actinomycin D ◽  
De Novo ◽  
Protein S ◽  
Male Rats ◽  
Hypoxic Exposure ◽  
De Novo Synthesis ◽  
Serum Erythropoietin

Abstract Significant increases in the serum erythropoietin of male rats occur after the end of a brief hypoxic exposure. These increases in the hormone are almost completely abolished when the kidneys are removed after the hypoxic exposure. Injection of puromycin or cycloheximide after the hypoxic exposure significantly decreases the subsequent increases in serum erythropoietin titers, whereas injections of actinomycin D at this time have no significant effect on erythropoietin levels. Injections of actinomycin D before the hypoxic exposure prevent the increase in serum erythropoietin that normally occurs. These findings suggest that a brief period of hypoxia initiates a DNA-dependent RNA synthesis that regulates the de novo ribosomal synthesis of protein(s) involved in the biogenesis of erythropoietin and that the kidney is essential for these reactions to occur.

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