scholarly journals Reversal of Aphidicolin-Directed Inhibition of DNA Synthesis in vivo and in vitro by Deoxyribonucleosides or Their 5'-Triphosphates

1980 ◽  
Vol 5 (2) ◽  
pp. 147-154 ◽  
Author(s):  
Dai Ayusawa ◽  
Kimiko Iwata ◽  
Susumu Ikegami ◽  
Takeshi Seno
Keyword(s):  
Dna Synthesis ◽  
Inhibition Of Dna Synthesis

scholarly journals Inhibition of Wool Follicle DNA Synthesis by Mimosine and Related 4(1H)-Pyridones

1976 ◽  
Vol 29 (3) ◽  
pp. 189 ◽  
Author(s):  
KA Ward ◽  
RL N Harris
Keyword(s):  
Dna Synthesis ◽  
Side Chain ◽  
Amino Acid Side Chain ◽  
Maximal Inhibition ◽  
Thin Slices ◽  
Wool Follicle ◽  
Inhibition Of Dna Synthesis ◽  
Primary Action

The. in vitro incorporation of [3Hjthymidine has been examined in thin slices of sheep skin. Most of the radioactivity (88 %) was incorporated into the bulb cells of the wool follicles, and the technique is therefore suitable for the study of some aspects of wool follicle DNA synthesis. The t1ffect of mimosine and a number of related 4(IH)-pyridones on [3Hjthymidine incorporation into sheep skin slices was t1xamined. Mimosine was shown to inhibit the incorporation at a concentration of 0�2mM. At this concentration, the incorporation of [3Hjuridine or ['4C]leucine was not affected. The inhibition of [3Hjthymidine incorporation was time dependent, 2 h of incubation being requ4"ed for maximal inhibition of DNA synthesis, and was readily reversible by removal of mimosine from the incubation medium. The 3-hydroxyl-4-oxo function of the pyridone ring appears to be directly involved in DNA synthesis inhibition. The amino acid side chain is not a toxophoric centre, but changes in its polarity have been shown to affect the inhibitory activity. The results suggest that the primary action of mimosine on the inhibition of wool biosynthesis in vivo is the inhibition of follicle bulb cell DNA synthesis and consequently of cell division.

Thrombopoietin-Induced Stimulation of Megakaryocyte- Enriched Bone Marrow Cultures

1979 ◽  
Author(s):  
K. L. Kellar ◽  
B. L. Evatt ◽  
C. R. McGrath ◽  
R. B. Ramsey
Keyword(s):  
Bone Marrow ◽  
Dna Synthesis ◽  
Bone Marrow Cells ◽  
Rabbit Plasma ◽  
Bone Marrow Cultures ◽  
Plasma Fractions ◽  
Marrow Cultures ◽  
Stimulation Of

Liquid cultures of bone marrow cells enriched for megakaryocytes were assayed for incorporation of 3H-thymidine (3H-TdR) into acid-precipitable cell digests to determine the effect of thrombopoietin on DNA synthesis. As previously described, thrombopoietin was prepared by ammonium sulfate fractionation of pooled plasma obtained from thrombocytopenic rabbits. A control fraction was prepared from normal rabbit plasma. The thrombopoietic activity of these fractions was determined in vivo with normal rabbits as assay animals and the rate of incorporation of 75Se-selenomethionine into newly formed platelets as an index of thrombopoietic activity of the infused material. Guinea pig megakaryocytes were purified using bovine serum albumin gradients. Bone marrow cultures containing 1.5-3.0x104 cells and 31%-71% megakaryocytes were incubated 18 h in modified Dulbecco’s MEM containing 10% of the concentrated plasma fractions from either thrombocytopenic or normal rabbits. In other control cultures, 0.9% NaCl was substituted for the plasma fractions. 3H-TdR incorporation was measured after cells were incubated for 3 h with 1 μCi/ml. The protein fraction containing thrombopoietin-stimulating activity caused a 25%-31% increase in 3H-TdR incorporation over that in cultures which were incubated with the similar fraction from normal plasma and a 29% increase over the activity in control cultures to which 0.9% NaCl had been added. These data suggest that thrombopoietin stimulates DNA synthesis in megakaryocytes and that this tecnique may be useful in assaying thrombopoietin in vitro.

scholarly journals RuvAB and RecG Are Not Essential for the Recovery of DNA Synthesis Following UV-Induced DNA Damage in Escherichia coli

Genetics ◽  
2004 ◽  
Vol 166 (4) ◽  
pp. 1631-1640 ◽  
Author(s):  
Janet R Donaldson ◽  
Charmain T Courcelle ◽  
Justin Courcelle
Keyword(s):  
Dna Damage ◽  
Dna Synthesis ◽  
Dna Lesions ◽  
Replication Forks ◽  
Wild Type ◽  
Replication Machinery ◽  
Dna Junctions ◽  
Fork Regression

Abstract Ultraviolet light induces DNA lesions that block the progression of the replication machinery. Several models speculate that the resumption of replication following disruption by UV-induced DNA damage requires regression of the nascent DNA or migration of the replication machinery away from the blocking lesion to allow repair or bypass of the lesion to occur. Both RuvAB and RecG catalyze branch migration of three- and four-stranded DNA junctions in vitro and are proposed to catalyze fork regression in vivo. To examine this possibility, we characterized the recovery of DNA synthesis in ruvAB and recG mutants. We found that in the absence of either RecG or RuvAB, arrested replication forks are maintained and DNA synthesis is resumed with kinetics that are similar to those in wild-type cells. The data presented here indicate that RecG- or RuvAB-catalyzed fork regression is not essential for DNA synthesis to resume following arrest by UV-induced DNA damage in vivo.

Potentiation of the bleomycin, arabinofuranosylcytosine and adriamycin-caused inhibition of DNA synthesis in lymphocytes by bestatin in vitro

1985 ◽  
Vol 21 (11) ◽  
pp. 1325-1330 ◽  
Author(s):  
G. Leyhausen ◽  
H.C. Schröder ◽  
D.K. Schuster ◽  
A. Maidhof ◽  
H. Umezawa ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Inhibition Of Dna Synthesis

scholarly journals Effect of incorporation of cidofovir into DNA by human cytomegalovirus DNA polymerase on DNA elongation.

1997 ◽  
Vol 41 (3) ◽  
pp. 594-599 ◽  
Author(s):  
X Xiong ◽  
J L Smith ◽  
M S Chen
Keyword(s):  
Dna Synthesis ◽  
Dna Polymerase ◽  
Human Cytomegalovirus ◽  
Chain Elongation ◽  
Exonuclease Activity ◽  
Dna Chain ◽  
Alternate Substrate

Cidofovir (CDV) (HPMPC) has potent in vitro and in vivo activity against human cytomegalovirus (HCMV), CDV diphosphate (CDVpp), the putative antiviral metabolite of CDV, is an inhibitor and an alternate substrate of HCMV DNA polymerase. CDV is incorporated with the correct complementation to dGMP in the template, and the incorporated CDV at the primer end is not excised by the 3'-to-5' exonuclease activity of HCMV DNA polymerase. The incorporation of a CDV molecule causes a decrease in the rate of DNA elongation for the addition of the second natural nucleotide from the singly incorporated CDV molecule. The reduction in the rate of DNA (36-mer) synthesis from an 18-mer by one incorporated CDV is 31% that of the control. However, the fidelity of HCMV DNA polymerase is maintained for the addition of the nucleotides following a single incorporated CDV molecule. The rate of DNA synthesis by HCMV DNA polymerase is drastically decreased after the incorporation of two consecutive CDV molecules; the incorporation of a third consecutive CDV molecule is not detectable. Incorporation of two CDV molecules separated by either one or two deoxynucleoside monophosphates (dAMP, dGMP, or dTMP) also drastically decreases the rate of DNA chain elongation by HCMV DNA polymerase. The rate of DNA synthesis decreases by 90% when a template which contains one internally incorporated CDV molecule is used. The inhibition by CDVpp of DNA synthesis by HCMV DNA polymerase and the inability of HCMV DNA polymerase to excise incorporated CDV from DNA may account for the potent and long-lasting anti-CMV activity of CDV.

scholarly journals Interaction between the DrosophilaCAF-1 and ASF1 Chromatin Assembly Factors

2001 ◽  
Vol 21 (19) ◽  
pp. 6574-6584 ◽  
Author(s):  
Jessica K. Tyler ◽  
Kimberly A. Collins ◽  
Jayashree Prasad-Sinha ◽  
Elizabeth Amiott ◽  
Michael Bulger ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Polytene Chromosomes ◽  
Normal Growth ◽  
Chromatin Assembly ◽  
Truncated Form ◽  
Assembly Factor ◽  
Development And Differentiation ◽  
Growth Development

ABSTRACT The assembly of newly synthesized DNA into chromatin is essential for normal growth, development, and differentiation. To gain a better understanding of the assembly of chromatin during DNA synthesis, we identified, cloned, and characterized the 180- and 105-kDa polypeptides of Drosophila chromatin assembly factor 1 (dCAF-1). The purified recombinant p180+p105+p55 dCAF-1 complex is active for DNA replication-coupled chromatin assembly. Furthermore, we have established that the putative 75-kDa polypeptide of dCAF-1 is a C-terminally truncated form of p105 that does not coexist in dCAF-1 complexes containing the p105 subunit. The analysis of native and recombinant dCAF-1 revealed an interaction between dCAF-1 and theDrosophila anti-silencing function 1 (dASF1) component of replication-coupling assembly factor (RCAF). The binding of dASF1 to dCAF-1 is mediated through the p105 subunit of dCAF-1. Consistent with the interaction between dCAF-1 p105 and dASF1 in vitro, we observed that dASF1 and dCAF-1 p105 colocalized in vivo inDrosophila polytene chromosomes. This interaction between dCAF-1 and dASF1 may be a key component of the functional synergy observed between RCAF and dCAF-1 during the assembly of newly synthesized DNA into chromatin.

Planarian regeneration: in vivo and in vitro effects of calcium and calmodulin on DNA synthesis

1983 ◽  
Vol 13 (1) ◽  
pp. 25-34 ◽  
Author(s):  
Isabelle Martelly ◽  
Annie Molla ◽  
Monique Thomasset ◽  
Albert Le Moigne
Keyword(s):  
Dna Synthesis ◽  
Planarian Regeneration ◽  
In Vitro Effects
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