CORTISOL INCREASES TRANSFECTION EFFICIENCY OF CELLS

DNA uptake can be facilitated by addition of physiological amounts of 11 beta-hydroxy glucocorticosteroids (such as cortisol) during transfe ction, In the presence of cortisol, but not of the inactive Il-keto gl ucocorticoid cortisone, twice as many cells uptake and express the rep orter gene, The effect is specific and dose-dependent; the amounts of glucocorticosteroids needed to enhance transfection efficiency are in the nanomolar range, which corresponds to the dissociation constant of glucocorticoids for the glucocorticoid receptor in vitro, This effect can be abolished by an excess of the glucocorticoid antagonist RU486, We infer that the activated cytoplasmic glucocorticoid receptors enha nce nuclear translocation of the incoming transfected DNA. (C) 1997 Fe deration of European Biochemical Societies.