ASSESSMENT OF GENE-EXPRESSION AND PEPTIDE SECRETION FROM INDIVIDUAL CELLS

We have developed an assay that allows one to monitor gene expression in and peptide secretion from individual cells. By combining the rever se hemolytic plaque with in situ hybridization, investigators can quan titate simultaneously the level of gene expression and the level of se cretion of a peptide. The method can be used in any system in which an appropriate antibody for the reverse hemolytic plaque assay and probe s complementary to the mRNA of interest are available. It can be used to monitor the level of mRNA and secretion of the peptide product, or expression of one gene and the secretion of another peptide. In this p aper we will describe the major steps of the method. We have used the pituitary lactotroph as a model to demonstrate the power of this techn ique. However, we believe that this method may be an important approac h to answer many questions regarding the cellular and molecular mechan isms that regulate the coupling of peptide secretion and gene expressi on at the single cell level.