ACID NUCLEAR EXTRACTS AS MEDIATORS OF GENE-TRANSFER AND EXPRESSION

In an attempt to demonstrate transfection-active DNA packaging protein s in the cell nucleus? we prepared acid nuclear extracts with perchlor ic acid and subsequent protein fractions by stepwise acetone precipita tion. The original extract and these fractions containing different co mpositions of nuclear proteins were used as DNA packaging agents, Afte r the formation of complexes between these protein fractions and repor ter genes, the addition of these complexes to the cells resulted in hi gh transfection rates. Gel electrophoresis shows that the most active fractions contain histone H1 and HMG17. HMG1 exhibits a smaller activi ty. This result was confirmed by positive transfection experiments wit h commercial histone H1. Our results show that the transfection activi ty of acid nuclear protein fractions and histone H1 is dependent on th e presence of calcium. (C) 1998 Elsevier Science B.V.