Interferon-related developmental regulator (IFRD1) is the human homologue of the rat early response protein PC4 and its murine homologue TIS7 [1]. The exact function of IFRD1 is unknown but it has been shown that PC4 is necessary to muscle differentiation and that it might have a role in signal transduction. This family also contains IFRD2 and its murine equivalent SKMc15 which are highly expressed soon after gastrulation and in the hepatic primordium, suggesting an involvement in early hematopoiesis [2].

1: The human homolog of the rodent immediate early response genes, PC4 and TIS7, resides in the lung cancer tumor suppressor gene region on chromosome 3p21. Latif F, Duh FM, Bader S, Sekido Y, Li H, Geil L, Zbar B, Minna JD, Lerman MI; Hum Genet 1997;99:334-341. PMID:9050919

2: Cloning of the human interferon-related developmental regulator (IFRD1) gene coding for the PC4 protein, a member of a novel family of developmentally regulated genes. Buanne P, Incerti B, Guardavaccaro D, Avvantaggiato V, Simeone A, Tirone F; Genomics 1998;51:233-242. PMID:9722946