Molecular Characterization of Phytochrome-interacting Nascent Polypeptide Associated Complex Protein in Arabidopsis thaliana

Nascent polypeptide associated complex (NAC) proteins bind to newly synthesized polypeptide chains from ribosome and are involved in various physiological processes. An in vitro pull-down assay demonstrated that the previously identified NAC protein interacts with phytochromes. Phytochrome-interacting NAC protein (PNAC) was expressed in the cytosol, and translocation of the PNAC protein into nucleus by irradiation was not observed. These findings suggest that PNAC is a possible cytosolic partner protein to phytochromes. Histochemical analysis of PNAC promoter-beta-glucuronidase (GUS) transgenic plants showed that PNAC expression was increased by light treatment, especially red light, indicating that phytochromes likely modulate PNAC gene expression.