| abstract |
A method of expression DNA in a cell comprises, in a cell that expresses a replication VpA factor, transfecting the cell with a vector, wherein (i) the vector contains a DNA, or is adapted to receive a DNA, in operative combination with a promoter for expression of the DNA; and (ii) extrachromosomal replication of the vector is dependent upon presence within the cell of the replication factor. Stable El maintenance of the vector and expression of the DNA is thereby achieved. Vectors for expression of DNA are provided as are assays for the effect of expression of DNAs in cells, the DNAs being H expressed from the vectors. |