Identification of the trans-activation domain and the nuclear location signals of human zinc finger protein HZF1 (ZNF16).

We previously characterized a C2H2-type zinc finger protein HZF1 (ZNF16) and demonstrated its important role in erythroid and megakaryocytic differentiation. This protein was located in nucleus. In this study, we first approved that HZF1 solely could activate lacZ reporter gene in yeast host Y190. This self-activation phenomenon together with structure and distribution of HZF1 suggested it as a potential transcription factor. By the auto-activation experiments and the luciferase reporter system and deletion mutation analysis, we further located the trans-activation domain at amino acid residences 49-197 within the non-zinc finger region of HZF1. An acidic residue-rich subregion (amino acids 49-105) was important for the trans-activation effect, but it could not function independently. By deletion mutation analysis, we also identified three nuclear location signals, which were located in the regions of amino acids 255-280, 328-360, and 460-490, respectively, and all of them within the zinc finger region.