scholarly journals Early induction of in vivo-in vitro hepatocyte replicative DNA synthesis(RDS) by nongenotoxic and genotoxic hepatocarcinogens in male F334 rats and B6C3F1 mice.

1995 ◽  
Vol 8 (3) ◽  
pp. 291-302 ◽  
Author(s):  
Kunie Yoshikawa
Keyword(s):  
Dna Synthesis ◽  
B6c3f1 Mice

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.

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

scholarly journals Monoclonal antibody to the interferon-inducible protein Leu-13 triggers aggregation and inhibits proliferation of leukemic B cells

Blood ◽  
1990 ◽  
Vol 76 (12) ◽  
pp. 2583-2593 ◽  
Author(s):  
SS Evans ◽  
DB Lee ◽  
T Han ◽  
TB Tomasi ◽  
RL Evans
Keyword(s):  
B Cells ◽  
Dna Synthesis ◽  
Lymphocytic Leukemia ◽  
Intercellular Adhesion Molecule ◽  
Intercellular Adhesion Molecule 1 ◽  
Adhesive Properties ◽  
Prolymphocytic Leukemia ◽  
Ifn Alpha

Abstract Interferon (IFN)-alpha inhibits DNA synthesis stimulated by low molecular weight B-cell growth factor (BCGF) in hairy cells in vitro, suggesting that the therapeutic efficacy of IFN-alpha in hairy cell leukemia (HCL) involves growth inhibition of malignant B cells. Evidence that the 16-Kd cell surface protein Leu-13 mediates an antiproliferative signal in T lymphocytes and is IFN-inducible in endothelial cells prompted us to examine the expression and functional role of this molecule in leukemic B cells. Leu-13 density, determined by flow cytometry, was upregulated in vitro and in vivo by IFN-alpha on malignant B cells from patients with HCL, chronic lymphocytic leukemia, and prolymphocytic leukemia. Monoclonal anti-Leu-13 triggered homotypic aggregation of leukemic B cells via an adhesion pathway that was not inhibited by antibodies to leukocyte function associated antigen-1 (LFA- 1) or intercellular adhesion molecule-1 (ICAM-1). Moreover, anti-Leu-13 potentiated the inhibitory effects of IFN-alpha on BCGF-stimulated DNA synthesis, assessed by [3H]-thymidine and [3H]-deoxyadenosine incorporation into DNA. These results indicate that Leu-13 is part of a novel IFN-inducible signaling pathway which may modify the growth and adhesive properties of leukemic B cells under physiologic or therapeutic conditions.

Use of in Vivo/In Vitro Unscheduled Dna Synthesis for Identification of Organ-Specific Carcinogens

1987 ◽  
Vol 17 (3) ◽  
pp. 245-277 ◽  
Author(s):  
Chie Furihata ◽  
Taijiro Matsushima ◽  
Byron E. Butterworth
Keyword(s):  
Dna Synthesis ◽  
Unscheduled Dna Synthesis ◽  
Organ Specific

SYNTHESIS OF DNA AND LECITHIN IN TISSUE CULTURE AND OESTROGEN RECEPTOR ACTIVITY IN RAT MAMMARY TUMOURS DEPENDENT ON AND INDEPENDENT OF THE OVARY

1979 ◽  
Vol 81 (2) ◽  
pp. 183-198 ◽  
Author(s):  
ANNE-MARIE SCOTT ◽  
SUSAN MURPHY ◽  
R. A. HAWKINS
Keyword(s):  
Tissue Culture ◽  
Dna Synthesis ◽  
Oestrogen Receptor ◽  
Receptor Activity ◽  
Sprague Dawley ◽  
Mammary Tumours ◽  
Sprague Dawley Rats ◽  
The Media

Dimethylbenz(a)anthracene (DMBA)-induced and transplanted rat mammary tumours (2 lines) were examined for oestrogen receptor activity, and for sensitivity to hormones in vivo (by ovariectomy) and in vitro (by tissue culture). In vivo, the growth of all tumours induced by the administration of DMBA in random-bred Sprague–Dawley rats was found to be dependent on the ovary, whilst in all transplanted tumours (12 TG-3 and six TG-5 lines), maintained in an inbred strain of Sprague–Dawley rats, growth was found to be independent of the ovary. In vitro, the capacity for DNA synthesis in DMBA-induced tumours was better maintained after 24 h when insulin (10 μg/ml) and corticosterone (5 μg/ml) or insulin, corticosterone and prolactin (each 5 μg/ml) were present in the medium (five out of 12 and eight out of 11 tumours respectively); no effect of hormones in the media was detected after 48 h. In the transplanted tumours, no effect of hormones on DNA synthesis was detected after either 24 or 48 h of culture. Synthesis of lecithin was not detectably influenced by the presence of hormones in either DMBA-induced or transplanted tumours. Oestrogen receptor concentrations were, on average, significantly higher in the DMBA-induced tumours than in either line of transplanted tumour. For 22 DMBA-induced tumours and 15 transplanted tumours, the effect of hormones in vitro (`response') was directly correlated with receptor concentration at time 0 (Spearman's ρ = + 0·59) and inversely correlated with the rate of DNA synthesis (`basal') at time 0 (Spearman's ρ = −0·62). No single parameter or pair of parameters permitted accurate distinction between the tumour types.

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