The formation of chromosome aberrations induced by alkylating agents such as mitomycin C has been shown to require the passage of the treated cell through S phase. However, the exact mechanisms by which mitomycin C-induced DNA lesions are translated into chromosome aberrations during S phase are not known. The purpose of these studies was to better understand the molecular basis of chromosome a...

A spillage of about 1200 gallons of benzene occurred during the loading of a ship, and 10 workers on a single shift were exposed to benzene. Shortly afterwards, an assay of the urine of these individuals showed that substantial amounts of phenol were being excreted. About three months after the incident samples of venous blood were taken from 10 individuals exposed to benzene and 11 men on a co...

Various types of DNA damage, induced by endo- and exogenous genotoxic impacts, may become processed into structural chromosome changes such as sister chromatid exchanges (SCEs) and chromosomal aberrations. Chromosomal aberrations occur preferentially within heterochromatic regions composed mainly of repetitive sequences. Most of the preclastogenic damage is correctly repaired by different repai...

DNA double-strand breaks (DSBs) are harmful lesions that arise mainly during replication. The choice of the sister chromatid as the preferential repair template is critical for genome integrity, but the mechanisms that guarantee this choice are unknown. Here we identify new genes with a specific role in assuring the sister chromatid as the preferred repair template. Physical analyses of sister ...

Through its functions in chromosome replication, segregation, and repair, the Smc5/6 complex has a central role in the maintenance of genome stability. The complex is part of the family of structural maintenance of chromosome protein complexes that also includes cohesin and condensin. Mutations in any of these complexes disrupt chromosome segregation and render cells hypersensitive to different...

It has been proposed that cells monitor chromatid catenation status after DNA replication and inhibit progression into mitosis until chromatids are correctly decatenated by topoisomerase II (TopoII). Studies in yeast have suggested that TopoII may interact with RecQ helicases during this process. Using ICRF187, a TopoII catalytic inhibitor that prevents chromatid decatenation without producing ...

The possibility that Ureaplasma urealyticum might play an important role in human infertility was first raised more than 20 years ago, but this association remains speculative. Considering the hypothesis that the pathogenicity of Ureaplasma urealyticum may depend on its serotypes, the clastogenic effects of different strains of Ureaplasma urealyticum, at concentrations of 10(3) CCU (color chang...

Chromatid catenation is actively monitored in human cells, with progression from G(2) to mitosis being inhibited when chromatids are insufficiently decatenated. Mitotic delay was quantified in normal and checkpoint-deficient human cells during treatment with ICRF-193, a topoisomerase II catalytic inhibitor that prevents chromatid decatenation without producing topoisomerase-associated DNA stran...

The SMC1/SMC3 heterodimer acts in sister chromatid cohesion, and recent data indicate a function in DNA double-strand break repair (DSBR). Since this role of SMC proteins has remained largely elusive, we explored interactions between SMC1 and the homologous recombination (HR) or non-homologous end-joining (NHEJ) pathways for DSBR in Saccharomyces cerevisiae. Analysis of conditional single- and ...