ABSTRACT
I. INTRODUCTION Transfection of DNA into eukaryotic cells is widely used to functionally analyze DNA, RNA, and proteins in a natural environment. For stable trans fections, those rare cells, in which integration of a vector has led to its perma nent persistence, usually are selected with a drug to which a vector-encoded protein confers resistance. In case of transient transfections, the time span of expression of a drug-resistance protein from the nonintegrated vector is too short for a selection. Thus, these cells are usually analyzed in bulk, which is often hampered by a huge background of untransfected cells. Now, the selection of transient and even stable transfectants using a surface marker has become practical, because of the development of rapid sorting of large numbers of cells without affecting their viability. In this chapter, we summa rize experiments done with selectable surface markers and show that selection of transfectants by cell sorting strongly facilitates the analysis of transient
transfectants. For stable transfection, this method clearly has certain advan tages over the use of drug selection.
