Analysis of cis-acting sequences and trans-acting factors regulating the interleukin-3 response element of the DUB-1 gene

The murine DUE-I gene is a hematopoietic-specific, immediate-early gene tha t encodes a growth-regulatory deubiquitinating enzyme. DUE-I contains an IL -3-inducible enhancer element that is activated in a JAK2-dependent, STAT5- independent manner. In this study, we have further characterized this novel IL-3 response element. Transcriptional reporter assays in Ba/F3 cells reve aled that two AP-1 sites, a GATA motif, and an Ets site are required for in duction of DUB-1 enhancer activity. Cel shift assays indicated that IL-3 ac tivates the binding of an AP-I complex containing JunD to the API sites and the binding of another protein complex to the Ets motif. The latter comple x was not detectable in Ba/F3 cells stably transfected with a dominant-nega tive mutant of JAK2. As previously shows, these cells do not express DUB-1 mRNA or protein. Furthermore, we demonstrated that GATA;I constitutively bi nds to the DUE-I enhancer element. The involvement of GATA-1 may be importa nt for the hematopoietic-restricted expression pattern of DUB-1. This combi nation of inducible and constitutive elements of the DUE-I enhancer appears to account for the unique STAT-independent expression characteristics of D UB-1. (C) 1999 Elsevier Science B.V. All rights reserved.