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Cytogenetic and Genome Research 2008The present study reports on the chromosomal expression and localization of aphidicolin-induced fragile sites in the standard karyotype of river buffalo (Bubalus...
The present study reports on the chromosomal expression and localization of aphidicolin-induced fragile sites in the standard karyotype of river buffalo (Bubalus bubalis, 2n = 50) with the aim of establishing a 'fragile site map' of the species. Totally, 400 aphidicolin-induced breakages were analyzed from eight young and clinically healthy animals, four males and four females; these breakages were localized in 106 RBG-negative chromosome bands or at the band-interband regions. The number of breakages per chromosome did not vary statistically 'among' the animals investigated but the differences among individual chromosomes were highly significant thus indicating that the chromosomal distribution of the breakages is not random and appears only partially related to chromosome length. Fragile sites were statistically determined as those chromosomal bands showing three or more breakages. In the river buffalo karyotype, 51 fragile sites were detected and localized on the standardized ideogram of the species. The most fragile bands were as follows: 9q213 with 24 breakages out of 400; 19q21 with 16, 17q21 and inacXq24 with 15, 15q23 with 13 and 13q23 with 12 breaks, respectively. Previous gene mapping analysis in this species has revealed that the closest loci to these fragile sites contain genes such as RASA1 and CAST (9q214), NPR3 and C9 (19q19), PLP and BTK (Xq24-q25), OarCP09 (15q24), and EDNRB (13q22) whose mutations are responsible for severe phenotypic malformations and immunodeficiency in humans as well as in mice and meat quality in pigs. Further cytogenetic and molecular studies are needed to fully exploit the biological significance of the fragile sites in karyotype evolution of domestic animals and their relationships with productive and reproductive efficiency of livestock.
Topics: Animals; Aphidicolin; Buffaloes; Cells, Cultured; Chromosome Banding; Chromosome Breakage; Chromosome Fragile Sites; Chromosome Mapping; Female; Karyotyping; Male; X Chromosome
PubMed: 18467845
DOI: 10.1159/000118760 -
Computers in Biology and Medicine Jul 1992A computer simulation model was developed and used to analyze the inhibitory effect of aphidicolin on the proliferation of Hela cells. Simulation results were compared...
A computer simulation model was developed and used to analyze the inhibitory effect of aphidicolin on the proliferation of Hela cells. Simulation results were compared with actual experimental results [Pedrali-Noy et al. (1980) Nuc. Acid Res. 8, 377] and were found to be in good agreement. Also, the simulation showed that aphidicolin caused cells to be accumulated at the G1/S boundary and that recruitment and synchrony occurred.
Topics: Aphidicolin; Cell Cycle; Cells, Cultured; Computer Simulation; HeLa Cells; Humans; Models, Biological; Software
PubMed: 1643850
DOI: 10.1016/0010-4825(92)90066-v -
Mutation Research Nov 1999The expression of aphidicolin (apc)-produced common fragile sites and chromosome aberrations observed 24 h after apc treatment was studied in a normal individual. The...
The expression of aphidicolin (apc)-produced common fragile sites and chromosome aberrations observed 24 h after apc treatment was studied in a normal individual. The chromosome lesions (gaps and breaks) induced by apc are expressed as full chromosomal aberrations in later cell divisions. We compared chromosome rearrangements or anomalies induced by apc (detected in 45.4% of metaphases analyzed) with those present in human neoplasia or involved in primate evolution. We found that 55.7% of deletions observed in our study coincided with deletions implicated in several types of neoplasia. However, none of 49 translocations observed in our study coincided with those described as recurrently associated with human neoplasia, probably due to their unbalanced nature. When chromosome aberrations detected in our study (only deletions and inversions were taken into account) were compared to those involved in primate evolution, we found a low rate of coincidence. The low coincidence between chromosome alterations in neoplasia and evolution and those observed in our study could be explained because we analyzed chromosome alterations that had not been selected, whereas those present in chromosome evolution and in neoplasia had been subjected to a selection process.
Topics: Aphidicolin; Chromosome Aberrations; Chromosome Deletion; Chromosome Disorders; Chromosome Fragile Sites; Chromosome Fragility; Female; Humans; Metaphase; Translocation, Genetic
PubMed: 10592317
DOI: 10.1016/s0027-5107(99)00125-6 -
Cancer Genetics and Cytogenetics Oct 1984A new class of fragile sites termed common fragile sites is induced by aphidicolin, an inhibitor of DNA polymerase alpha. Analysis of these common fragile sites and...
A new class of fragile sites termed common fragile sites is induced by aphidicolin, an inhibitor of DNA polymerase alpha. Analysis of these common fragile sites and cancer chromosome breakpoints indicates that eight fragile sites are in bands with cancer breakpoints. This is unlikely to be due to chance (p less than 0.01). Common fragile sites are in both bands where breaks occur in carcinoma of the lung and in carcinoma of the ovary. Common fragile sites are in bands with breaks leading to constitutional chromosome abnormalities associated with cancer: hereditary renal cell carcinoma and aniridia-Wilms' tumor complex. Common fragile sites, thus, may predispose to chromosome breaks and rearrangements in cancer.
Topics: Aphidicolin; Chromosome Fragile Sites; Chromosome Fragility; Chromosome Mapping; DNA, Neoplasm; Diterpenes; Humans; Nucleic Acid Synthesis Inhibitors
PubMed: 6434179
DOI: 10.1016/0165-4608(84)90060-8 -
The Journal of Parasitology Aug 1998We have previously demonstrated that DNA polymerase activity of Entamoeba histolytica is inhibited by aphidicolin, which is a specific inhibitor of eukaryotic nuclear...
We have previously demonstrated that DNA polymerase activity of Entamoeba histolytica is inhibited by aphidicolin, which is a specific inhibitor of eukaryotic nuclear replicative DNA polymerases. The present study was aimed to evaluate the effect of aphidicolin on growth and DNA synthesis by this parasite. Aphidicolin blocked the growth of axenic E. histolytica strain HM-1:IMSS. DNA synthesis was also inhibited by aphidicolin when assayed by incorporation of [3H]thymidine into the DNA. The inhibitory effect of aphidicolin on the growth of E. histolytica was abrogated by removal of the drug, and exposure to 3 microg/ml of the drug for at least 48 hr had little effect on the viability. Synchronous growth was observed in the recovery phase after removal of aphidicolin.
Topics: Animals; Aphidicolin; DNA, Protozoan; Entamoeba histolytica; Enzyme Inhibitors; Nucleic Acid Synthesis Inhibitors
PubMed: 9714225
DOI: No ID Found -
The Tokai Journal of Experimental and... Dec 1998We have detected and characterized DNA polymerase activity in cell extracts from trophozoites of Entamoeba histolytica and have found that the activity of E. histolytica...
We have detected and characterized DNA polymerase activity in cell extracts from trophozoites of Entamoeba histolytica and have found that the activity of E. histolytica is inhibited by aphidicolin, which is a specific inhibitor of eukaryotic nuclear replicative DNA polymerases. The present study was aimed to evaluate the effect of aphidicolin on growth and DNA synthesis by this parasite. Aphidicolin blocked the growth of axenic E. histolytica strain HM-1: IMSS. DNA synthesis was also inhibited by aphidicolin when assayed by incorporation of [3H] thymidine into the DNA. The inhibitory effect of aphidicolin on the growth of E. histolytica was abrogated by removal of the drug, and exposure to 3 microg/ml of the drug for at least 48 hr had little effect on the viability. Synchronous growth was observed in the recovery phase after removal of aphidicolin.
Topics: Animals; Aphidicolin; DNA, Protozoan; DNA-Directed DNA Polymerase; Entamoeba histolytica; Enzyme Inhibitors; Nucleic Acid Synthesis Inhibitors
PubMed: 10622640
DOI: No ID Found -
Life Science Alliance Apr 2023Eukaryotic genomes are duplicated from thousands of replication origins that fire sequentially forming a defined spatiotemporal pattern of replication clusters. The...
Eukaryotic genomes are duplicated from thousands of replication origins that fire sequentially forming a defined spatiotemporal pattern of replication clusters. The temporal order of DNA replication is determined by chromatin architecture and, more specifically, by chromatin contacts that are stabilized by RIF1. Here, we show that RIF1 localizes near newly synthesized DNA. In cells exposed to the DNA replication inhibitor aphidicolin, suppression of RIF1 markedly decreased the efficacy of isolation of proteins on nascent DNA, suggesting that the isolation of proteins on nascent DNA procedure is biased by chromatin topology. RIF1 was required to limit the accumulation of DNA lesions induced by aphidicolin treatment and promoted the recruitment of cohesins in the vicinity of nascent DNA. Collectively, the data suggest that the stabilization of chromatin topology by RIF1 limits replication-associated genomic instability.
Topics: Chromatin; Aphidicolin; Telomere-Binding Proteins; DNA; DNA Replication
PubMed: 36746532
DOI: 10.26508/lsa.202101186 -
Journal of Immunology (Baltimore, Md. :... Oct 1993To test whether DNA injury contributes to TNF-induced cytotoxicity, we attempted to enhance DNA injury by inhibiting its repair and then assessing effects on...
To test whether DNA injury contributes to TNF-induced cytotoxicity, we attempted to enhance DNA injury by inhibiting its repair and then assessing effects on cytotoxicity. DNA repair, assayed as unscheduled DNA synthesis, was first detected in TNF-sensitive targets by 2-3 h of incubation with TNF. Targets resistant to TNF cytotoxicity did not demonstrate significant repair replication. Repair preceded the detection of TNF-induced DNA injury, which was subsequently demonstrated by a double-stranded DNA fragmentation assay, sedimentation of DNA in neutral and alkaline sucrose gradients, and gel electrophoresis of extracted DNA. This suggested that early during exposure to TNF, DNA repair proceeds more rapidly than strand breakage. To inhibit repair, nontoxic concentrations of aphidicolin (inhibitor of DNA polymerase-alpha) and dideoxythymidine (inhibitor of DNA polymerase-beta and gamma) were used. Aphidicolin inhibited repair and consistently sensitized to TNF cytotoxicity, decreasing the ID50 for TNF at least 10- to 50-fold. In contrast, dideoxythymidine had no effect on repair or cytotoxicity. Deoxycytidine, which competitively inhibits binding of aphidicolin to DNA polymerase, blocked the sensitization in a concentration-dependent fashion. In targets sensitized with aphidicolin, TNF-induced strand breakage was accelerated, being detected by 4 h of culture in the sucrose gradient assay. Sensitization to TNF was not due to a heightened activation of poly (ADP-ribose) polymerase. These results indicate that TNF-induced strand breakage participates in TNF-induced cytotoxicity and that the level of DNA repair plays a role in determining relative sensitivity of targets.
Topics: Aphidicolin; Cell Survival; DNA; DNA Damage; DNA Repair; DNA Replication; Dideoxynucleosides; Female; Humans; Poly(ADP-ribose) Polymerases; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha
PubMed: 8376804
DOI: No ID Found -
International Journal of Pharmaceutics Mar 2000A series of labdans and their derivatives have been identified as novel potential antileishmanial drugs using an in vitro test system against extracellular promastigotes... (Comparative Study)
Comparative Study
A series of labdans and their derivatives have been identified as novel potential antileishmanial drugs using an in vitro test system against extracellular promastigotes and intracellular amastigotes of Leishmania donovani in murine macrophages (Kayser, O., Kiderlen, A.F., 1998. In vitro activity of leishmanicidal labdanes and related compounds. Proceedings of the Ninth International Congress of Parasitology, Monduzi Editore, Bologna, 925-929). Of these compounds, aphidicolin, a tetradecanhydro-3,9-dihydroxy-4,11b-dimethyl-8, 11a-methano-11aH-cyclo-hepta[a]naphthalin-4,9-dimethanol+ ++ (Fig. 1), was shown to be highly active at concentrations in the microgram range (EC(50) = 0.16 microg/ml). To improve drug targeting effects aphidicolin was formulated as nanosuspension and retested for its enhanced activity (EC(50) = 0.003 microg/ml).
Topics: Animals; Antiprotozoal Agents; Aphidicolin; Bone Marrow Cells; Dimethyl Sulfoxide; Drug Delivery Systems; Inhibitory Concentration 50; Leishmania; Macrophages; Mice; Mice, Inbred C57BL; Polysorbates; Suspensions
PubMed: 10699730
DOI: 10.1016/s0378-5173(99)00434-2 -
Mutation Research Apr 2010The instability of common fragile sites (CFSs) contributes to the development of a variety of cancers. The ATR-dependent DNA damage checkpoint pathway has been...
The instability of common fragile sites (CFSs) contributes to the development of a variety of cancers. The ATR-dependent DNA damage checkpoint pathway has been implicated in maintaining CFS stability, but the mechanism is incompletely understood. The goal of our study was to elucidate the action of the ATR protein in the CFS-specific ATR-dependent checkpoint response. Using a chromatin immunoprecipitation assay, we demonstrated that ATR protein preferentially binds (directly or through complexes) to fragile site FRA3B as compared to non-fragile site regions, under conditions of mild replication stress. Interestingly, the amount of ATR protein that bound to three regions of FRA3B peaked at 0.4microM aphidicolin (APH) treatment and decreased again at higher concentrations of APH. The total amounts of cellular ATR and several ATR-interacting proteins remained unchanged, suggesting that ATR binding to the fragile site is guided initially by the level of replication stress signals generated at FRA3B due to APH treatment and then sequestered from FRA3B regions by successive signals from other non-fragile site regions, which are produced at the higher concentrations of APH. This decrease in ATR binding to fragile site FRA3B at the higher concentrations of APH may account for the increasing number of chromosome gaps and breaks observed under the same conditions. Furthermore, inhibition of ATR kinase activity by treatment with 2-aminopurine (2-AP) or by over-expression of a kinase-dead ATR mutant showed that the kinase activity is required for the binding of ATR to fragile DNAs in response to APH treatment. Our results provide novel insight into the mechanism for the regulation of fragile site stability by ATR.
Topics: Acid Anhydride Hydrolases; Aphidicolin; Ataxia Telangiectasia Mutated Proteins; Cell Cycle Proteins; DNA Damage; DNA Replication; Enzyme Inhibitors; Genomic Instability; Humans; Neoplasm Proteins; Protein Kinases; Protein Serine-Threonine Kinases
PubMed: 20060399
DOI: 10.1016/j.mrfmmm.2009.12.012