H1 AND HMG17 EXTRACTED FROM CALF THYMUS NUCLEI ARE EFFICIENT DNA CARRIERS IN GENE-TRANSFER

In this article we describe the chromatographic separation of acid nuc lear protein fractions which have previously been shown to be active i n DNA transfection experiments. By combining anionic and cationic ion exchangers, we were able to separate and identify some of the active p roteins. In addition to HMG1, already known for its transfection activ ity, we have identified histone H1 and HMG17 as further transfection-a ctive proteins. The highest transfection activity was associated with H1 and another nonidentified protein showing a somewhat higher electro phoretic mobility than H1. We have also found that the presence of CaC l2 in a low concentration in the cell culture medium is an important r equirement for transfection.