CLONING OF NRF1, AN NF-E2-RELATED TRANSCRIPTION FACTOR, BY GENETIC SELECTION IN YEAST

We have devised a complementation assay in yeast to clone mammalian tr anscriptional activators and have used it to identify a human basic le ucine-zipper transcription factor that we have designated Nrf1 for NF- E2-related factor 1. Nrf1 potentially encodes a 742-aa protein and dis plays marked homology to the mouse and human NF-E2 transcription facto rs. Nrf1 activates transcription via NF-E2 binding sites in yeast cell s. The ubiquitous expression pattern of Nrf1 and the range of promoter s containing the NF-E2 binding motif suggest that this gene may play a role in the regulation of heme synthesis and ferritin genes.