CONNEXIN-43 EXPRESSION IN NORMAL AND IRRADIATED MOUSE SKIN

The expression of connexin 43 (Cx43) in normal and irradiated mouse sk in was evaluated using immunofluorescence with polyclonal antisera to Cx43 on cryostat sections. One week after the start of daily irradiati on with 3 Gy, enhanced immunoreactivity in basal cells and in the lowe r part of the spinous layer of the epidermis was detected. In hypertro phic and hyperplastic skin, about 3 weeks after irradiation, a further increase in the expression of Cx43 was found in the epidermis as well as in the dermis, Western blot analysis of normal and irradiated skin homogenates confirmed the increased Cx43 protein concentration in the skin. In nuclear extracts of the same preparations, increased AP-l-bi nding activity was found. These data suggest that the gap-junction pro tein is expressed in response to irradiation of the skin and may be re lated to the subsequent hyperproliferative response which is associate d with accelerated repopulation. (C) 1997 by Radiation Research Societ y.