ABSTRACT
When one desires to produce a protein that is most likely to be successfully synthesized in a mammalian cell, the recommended process depends on several different criteria, most importantly, the amount of the protein that is required. Microgram to milligram quantities of either cytoplasmic or secreted proteins can most efficiently be produced by transient expression using virus-derived vectors that produce a lytic infection in mammalian cells. A higher percentage of stable clones can be achieved by several different methods, but this is not necessary for isolating clones with high level expression. Cells can be seeded directly following introduction of DNA into 96-well dishes, and then selected for a marker gene. If a higher level of expression is desired, a group of high level expressing clones are individually selected for gene amplification.
