Evidence that the product of the xrs gene is predominantly involved in the repair of a subset of radiation-induced interphase chromosome breaks rejoining with fast kinetics

Journal Article · Fri Apr 01 04:00:00 EST 1994 · Radiation Research; (United States)

DOI:https://doi.org/10.2307/3578844· OSTI ID:6443841

Okayasu, R; Iliakis, G ^[1]

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1. Thomas Jefferson Univ., Philadelphia, PA (United States)

We classified interphase chromosome breaks into [alpha] and [beta] forms to study the requirement for the xrs gene product in the repair of each of these forms of damage. The [alpha] form of damage comprises radiation-induced interphase chromosome breaks whose rejoining is slow and sensitive to treatment with [beta]-arabinofuranosyladenine ([beta]-araA), whereas the [beta] form of damage comprises interphase chromosome breaks whose rejoining is fast and sensitive to treatment in hypertonic medium. Interphase chromosome breaks of the [alpha] form are visualized in plateau-phase cells by premature chromosome condensation (PCC) carried out in the absence of any treatment during the condensation period. More interphase chromosome breaks of the [beta] form are not visualized in experiments using standard PCC protocols but can be uncovered by treatment in hypertonic growth medium during the period allowed for PCC. In the present report, we show that the yield of interphase chromosome breaks of the [alpha] form is similar in CHO and xrs-5 cells and demonstrate that xrs-5 cells rejoin this type of interphase chromosome breaks with an efficiency similar to that observed in repair-proficient CHO cells. Furthermore, we provide evidence supporting the notion that xrs-5 cells are deficient in the rejoining of the [beta] form of interphase chromosome breaks. These results strongly suggest that the product of the xrs gene is required predominantly in the repair of the [beta] form of interphase chromosome damage and emphasize the need for discrimination between different forms of interphase chromosome breaks in irradiated cells. 41 refs., 8 figs., 1 tab.

• OSTI ID: 6443841
• Journal Information: Radiation Research; (United States), Journal Name: Radiation Research; (United States) Vol. 138:1; ISSN 0033-7587; ISSN RAREAE
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
560120 -- Radiation Effects on Biochemicals
Cells
& Tissue Culture
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CHO CELLS
CHROMOSOMAL ABERRATIONS
CHROMOSOME BREAKAGE
DAMAGE
GENE REGULATION
KINETICS
MUTANTS
MUTATIONS
RADIATION INDUCED MUTANTS
RADIOINDUCTION
REACTION KINETICS
REPAIR