Inhibition of DNA synthesis prevents mitotic entry through the action of the S-phase checkpoint. We have isolated S-phase arrest-defective (sad) mutants that show lethality in the presence of the DNA synthesis inhibitor hydroxyurea (HU). Several of these mutants show phenotypes consistent with inappropriate mitotic entry in the presence of unreplicated DNA, indicating a defect in the S-phase ch...

Small interfering RNA molecules (siRNA) hold great promise to specifically target cytoprotective factors to enhance cancer therapy. Like antisense RNA strategies, however, the use of siRNA is limited because of in vivo instability. As a first step to overcome delivery issues, a series of graft copolymers of polyethylene glycol and polyethylenimine (PEI-g-PEG) were synthesized and investigated a...

The extensive analysis of the impact of segmental aneuploidy by Lindsley et al. (1972) showed that there are relatively few haplo-lethal loci in the genome and that, with one exception, all loci are triplo-viable. The exceptional locus, which lies in salivary gland chromosome region 83D-E, is associated with lethality when present in either one or three doses in an otherwise diploid individual ...

The immunomodulatory activity of Cod liver oil (CLO) was evaluated by mice lethality test, carbon clearance assay, neutrophil adhesion test, cyclophosphamide-induced neutropenia, indirect haemagglutination test and effect on serum immunoglobulin levels. CLO was administered orally at a dose of 0.5 g/kg or 1 g/kg body weight. In mice lethality test, low dose of CLO (0.5 g/kg, po) produced 40% de...

VRK1 is a nuclear Ser-Thr chromatin kinase that does not mutate in cancer, and overexpressed many types of tumors associated with poor prognosis. Chromatin phosphorylates several transcription factors, including p53, histones proteins implicated DNA damage response pathways. In the context cell proliferation, regulates entry cycle, condensation G2/M, Golgi fragmentation, Cajal body dynamics env...

Intrinsic postzygotic reproductive isolation is thought to result from the substitution of multiple harmless or beneficial genetic differences between species that are incidentally deleterious when combined in species hybrids, causing hybrid sterility or inviability. Genetic variability for hybrid sterility or inviability phenotypes is, however, rarely assessed in natural populations. Here, we ...

Non-homologous end-joining (NHEJ) of DNA double-strand breaks (DSBs) is mediated by two protein complexes comprising Ku80/Ku70/DNA-PKcs/Artemis and XRCC4/LigaseIV/XLF. Loss of Ku or XRCC4/LigaseIV function compromises the rejoining of radiation-induced DSBs and leads to defective V(D)J recombination. In this study, we sought to define how XRCC4 and Ku80 affect NHEJ of site-directed chromosomal ...

Since transformation of hamster cells in vitro by simian virus 40 (SV40) is a rare event in a homogeneously infected cell population, physiochemical studies of the events of virus transformation are difficult. Similarly, other deoxyribonucleic acid-containing oncogenic viruses produce transformed-cell foci in vitro with low efficiency. Sublethal doses of X-ray irradiation, as well as preincubat...

Development of novel approaches linking the physical characteristics of particles with biological responses are of high relevance for the field of particle therapy. In radiobiology, the clonogenic survival of cells is considered the gold standard assay for the assessment of cellular sensitivity to ionizing radiation. Toward further development of next generation biodosimeters in particle therap...

Gap junctional intercellular communication (GJIC) is essential in the maintenance of tissue homeostasis and has been implicated in tumor suppression. Recent studies have indicated that GJIC is also involved in cellular stress responses to low dose ionizing radiation, UV light and hydrogen peroxide. However, the contribution of GJIC to the heat stress response has not yet been elucidated. We her...