GFZF, a Glutathione S -Transferase Protein Implicated in Cell Cycle Regulation and Hybrid Inviability, Is a Transcriptional Coactivator

Abstract

ABSTRACT The core promoters of protein-encoding genes play a central role in regulating transcription. M1BP is a transcriptional activator that associates with a core promoter element known as Motif 1 that resides at thousands of genes in Drosophila . To gain insight into how M1BP functions, we identified an interacting protein called GFZF. GFZF had been previously identified in genetic screens for factors involved in maintenance of hybrid inviability, the G 2 -M DNA damage checkpoint, and RAS/mitogen-activated protein kinase (MAPK) signaling, but its contribution to these processes was unknown. Here, we show that GFZF resides in the nucleus and functions as a transcriptional coactivator. In addition, we show that GFZF is a glutathione S -transferase (GST). Thus, GFZF is the first transcriptional coactivator with intrinsic GST activity, and its identification as a transcriptional coactivator provides an explanation for its role in numerous biological processes.