113 – Reversible biophysical changes of DNAs from in vitro cultured non-tumour cells

Med. Sci. Res., 16, 1988, pp. 359-361. Available in English only ABSTRACT: We have previously shown that DNA fom plant Crown-gall tumour tissues is highly relaxed and thereby very susceptible to various DNA-destabilizing agents which, in contrast, do not affect DNA from healthy tissues. In vitro DNA strand separation (chain unpairing), the rate of in vitro DNA synthesis and in vivo increase in tumor cell multiplication are colsely correlated. Here we report that plant non-tumour cell DNA may temporarily undergo conformational changes when these cells are cultured in vitro in the presence of opines (octopine, nopaline, lysopine which accumulate in Crown-gall tissues or dl-ethionine (a known carcinogen in mammalian tissues). The induced DNA double-strand destabilisation and consequent increase in template activity are shown to be reversible under our experimental conditions.Voir le document