hnRNP K Supports High-Amplitude D Site-Binding Protein mRNA ( Dbp mRNA) Oscillation To Sustain Circadian Rhythms

Abstract

Circadian gene expression is defined by the gene-specific phase and amplitude of daily oscillations in mRNA and protein levels. D site-binding protein mRNA ( Dbp mRNA) shows high-amplitude oscillation; however, the underlying mechanism remains elusive. Here, we demonstrate that heterogeneous nuclear ribonucleoprotein K (hnRNP K) is a key regulator that activates Dbp transcription via the poly(C) motif within its proximal promoter. Biochemical analyses identified hnRNP K as a specific protein that directly associates with the poly(C) motif in vitro .