TREATMENT WITH A POLYAMINE ANALOG ALTERS DNA-MATRIX ASSOCIATION IN HELA-CELL NUCLEI - A NUCLEOID HALO ASSAY

The polyamine analog 1,14-bis(ethylamino)-5,10-diazatetradecane (BE-4- 4-4) depletes polyamines and inhibits the growth of tumor cells in tis sue culture. We treated HeLa cells in culture with BE-4-4-4 for differ ent time periods to produce different degrees of polyamine depletion. The cells were lysed and dehistonized to obtain nucleoids containing D NA attached to the nuclear matrix. Titration of the nucleoids with pro pidium iodide caused an uncoiling of negatively supercoiled DNA, resul ting in the formation of a halo surrounding the nucleoid periphery. Th e halo diameters in both the BE-4-4-4-treated cells and the untreated control cells were measured using a fluorescence image analysis system . As compared to the control cells, the BE-4-4-4-treated cells showed a 20-25% decrease in halo diameter, indicating that there was less rel axation of the negative supercoils in the nuclear DNA of the BE-4-4-4- treated cells than in the controls.