When eukaryotic cells are stimulated to undergo mitogenesis or differentiation, the expression of a small subset of genes, termed early response or immediate early genes, is rapidly activated. Many early response genes encode transcriptional regulators, for example, nerve growth factor-induced clones C and A, also called EGR4 and EGR1, respectively.

By use of fluorescence in situ hybridization, Crosby et al. (1992) localized the human EGR4 gene to 2p13. Barrow et al. (1994) demonstrated that the homologous gene in the mouse (Early Growth Response 4 ) maps to chromosome 6 in a region of conserved homology of synteny with human chromosome 2.