Immunogens created by DNA-mediated gene transfer

One of the major opportunities that molecular biology has presented is the ability to determine DNA sequences at will. This information, followed by either subcloning or oligonucleotide synthesis, allows the easy analysis of expression, at least as measured by RNA transcription. It is extremely useful to be able to assay protein as well as mRNA expression, because proteins mediate phenotypes rather than RNA itself. Many times the protein is present in either low concentration or is obscured by other similar-sized proteins. To detect a specific protein in such circumstances, antibodies are very useful. Antibodies can be used to detect the synthesis of a protein both by radioimmunoprecipitation or immunoblots (Western blots) using materials from cells or tissues; by immunohistochemical means, antibodies can be used to localize the expression of a particular molecule among the cells of a tissue. The ability to localize protein expression on a cell-by-cell basis is extraordinarily useful in trying to understands how gene expression regulates development. The author's goal in this chapter is to first discuss the two alternative methods for production of antibodies from DNA sequences. One way promulgated, uses synthetic peptides (1), and the other utilizes expression of transfected genes in L cells