CHARACTERIZATION OF GENE-EXPRESSION IN RESTING AND ACTIVATED MAST-CELLS

To characterize gene expression in activated mast cells more comprehen sively than heretofore, we surveyed the changes in genetic transcripts by the method of serial analysis of gene expression in the RBL-2H3 li ne of rat mast cells before and after they were stimulated through the ir receptors with high affinity for immunoglobulin E (Fc epsilon RI). A total of 40,759 transcripts derived from 11,300 genes were analyzed. Among the diverse genes that had not been previously associated with mast cells and that were constitutively expressed were those for the c ytokine macrophage migration inhibitory factor neurohormone receptors such as growth hormone-releasing factor and melatonin and components o f the exocytotic machinery. In addition, several dozen transcripts wer e differentially expressed in response to antigen-induced clustering o f the Fc epsilon RI. Included among these were the genes for preprorel axin, mitogen-activated protein kinase kinase 3, and the dual specific ity protein phosphatase, rVH6. Significantly, the majority of genes di fferentially expressed in this well-studied model of mast cell activat ion have not been identified before this analysis.