Identification of mouse Jun dimerization protein 2 as a novel repressor ofATF-2

A mouse cDNA that encodes a DNA-binding protein was identified by yeast two -hybrid screening, using activating transcription factor-2 (ATF-2) as the b ait. The protein contained a bZIP (basic amino acid-leucine zipper region) domain and its amino acid sequence was almost identical to that of rat Jun dimerization protein 2 (JDP2). Mouse JDP2 interacted with ATF-2 both in vit ro and in vivo via its bZIP domain. It was encoded by a single gene and var ious transcripts were expressed in all tested tissues of adult mice, as wel l as in embryos, albeit at different levels in various tissues. Furthermore , mouse JDP2 bound to the cAMP-response element (CRE) as a homodimer or as a heterodimer with ATF-2, and repressed CRE-dependent transcription that wa s mediated by ATF-2, JDP2 was identified as a novel repressor protein that affects ATF-2-mediated transcription. (C) 2001 Federation of European Bioch emical Societies. Published by Elsevier Science B.V. All rights reserved.