Nac1 interacts with the POZ-domain transcription factor, Miz1

Mark A Stead,Stephanie C Wright

doi:10.1042/bsr20140049

Abstract

Nac1 (nucleus accumbens 1) is a POZ (poxvirus and zinc finger)-domain transcriptional repressor that is expressed at high levels in ovarian serous carcinoma. Here we identify Nac1 as a novel interacting partner of the POZ-domain transcriptional activator, Miz1 (Myc-interacting zinc-finger protein 1), and using chemical crosslinking we show that this association is mediated by a heterodimeric interaction of the Nac1 and Miz1 POZ domains. Nac1 is found in discrete bodies within the nucleus of mammalian cells, and we demonstrate the relocalization of Miz1 to these structures in transfected HeLa cells. We show that siRNA (small interfering RNA)-mediated knockdown of Nac1 in ovarian cancer cells results in increased levels of the Miz1 target gene product, p21Cip1. The interaction of Nac1 with Miz1 may thus be relevant to its mechanism of tumourigenesis in ovarian cancer.

Highlights

nucleus accumbens 1 (Nac1) was originally identified as the protein product of a cocaine-inducible transcript in the nucleus accumbens of the rat brain [1], and more recently it has emerged as a transcriptional repressor that functions as part of the network involved in embryonic stem cell self-renewal [2]
Myc-interacting zinc-finger protein 1 (Miz1) interacts with Nac1 in yeast two-hybrid assays and in mammalian cells The transcriptional properties of Miz1 may be modulated by the interaction of its N-terminal poxvirus and zinc finger (POZ) domain with other POZ domain transcription factors [48]
To identify novel interacting partners of Miz1, we used yeast two-hybrid assays to analyse the interaction of its POZ domain (Miz1 residues 1–115) with the POZ domains isolated from 32 POZ-domain transcription factor (POZ-TF); the well-characterized interaction between the Miz1- and BCL6 POZ domains served as a positive control

Summary

Introduction

Nac1 (nucleus accumbens 1) was originally identified as the protein product of a cocaine-inducible transcript in the nucleus accumbens of the rat brain [1], and more recently it has emerged as a transcriptional repressor that functions as part of the network involved in embryonic stem cell self-renewal [2]. Nac1 does not contain a zinc-finger DNA-binding domain as is found in most POZ-TFs; it is assumed that its C-terminal BEN (B-cell translocation gene 3 associated nuclear protein, E5R and Nac1) domain interacts with the promoters of target genes as has been recently reported for other BEN-domain transcriptional repressors [26].

Results

Conclusion