X-IRRADIATION-INDUCED DISORGANIZATION OF CYTOSKELETAL FILAMENTS AND CELL CONTACTS IN HT29 CELLS

Organization of cytoskeleton and cell contacts were studied by immunoc hemistry and electron microscopy in confluent HT29 cultured cells foll owing exposure to 0.5 and 1.0 Gy doses of X-ray. Microtubules were res istant to irradiation, whereas, the actin and intermediate filaments d isrupted rapidly following the treatment and their components appeared as clumps of actin and cytokeratin aggregates in the cytoplasm as dem onstrated by immunochemistry. Loss of cell contacts and decrease in th e number of desmosomes was also characteristic of irradiated cells. El ectron microscopy revealed intact desmosomes in control cells and abno rmal desmosomes in the irradiated samples characterized by the absence of tono-filaments. The perinuclear filament network and cortical fila ments were well detectable by electron microscopy. Under the effect of irradiation, the perinuclear filaments almost disappeared and, at the same time, small bundles of filaments were formed irregularly in the cytoplasm associated with amorphous material.