HSF2BP represses BNC1 transcriptional activity by sequestering BNC1 to the cytoplasm

Basonuclin (BNC1), a zinc finger transcriptional factor, is essential for mouse spermatogenesis. However, the regulatory mechanisms of BNC1 in spermatogenesis are poorly understood. In this study, we identified HSF2BP, a testis-specific binding protein of HSF2, as a binding partner of BNC1 by using yeast two-hybrid screening. HSF2BP could interact with and inhibit BNC1 transcriptional activity without affecting its expression level. Moreover, coexpression of HSF2BP with BNC1 resulted in a striking redistribution of BNC1 to the cytoplasm. These data suggest that HSF2BP may play a pivotal role in regulating BNC1 transcriptional activity and subcellular localization during spermatogenesis. Structured summary of protein interactions: Bnc1 physically interacts with HSF2BP by two hybrid (View interaction) Bnc1 and HSF2BP colocalize by fluorescence microscopy (View interaction) Bnc1 physically interacts with HSF2BP by anti tag coimmunoprecipitation (View Interaction: 1, 2) (C) 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.