A gene, cMG1, whose expression is transiently activated in growth factor stimulated epithelial cells has been identified by differential screening. Overlapping cDNA recombinants derived from cMG1 mRNA have been sequenced and shown to encode a protein of 338 amino acids. Database searches have revealed no similarities between cMG1 and other genes, except that over a 67-amino acid region the cMG1 protein shows 72% identity to the product of the TIS11 gene, a TPA-induced sequence in Swiss 3T3 cells. The results suggest that these two genes code for a novel type of early response gene.