1. hnRNP K supports high-amplitude D site-binding protein (Dbp) mRNA oscillation to sustain circadian rhythms.
- Author
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Kwangho Kwon, Paul, Kyung-Ha Lee, Ji-hyung Kim, Sookil Tae, Seokjin Ham, Young-Hun Jeong, Sung Wook Kim, Byunghee Kang, Hyo-Min Kim, Jung-Hyun Choi, Hee Yi, Hyun-Ok Ku, Tae-Young Roh, Chunghun Lim, and Kyong-Tai Kim
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CIRCADIAN rhythms ,OSCILLATIONS ,MOLECULAR clock ,MESSENGER RNA ,CLOCK genes ,PROTEINS ,PROTEIN expression - 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 (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. Interestingly, we further confirmed the rhythmic binding of endogenous hnRNP K within the Dbp promoter through chromatin immunoprecipitation as well as the cycling expression of hnRNP K. Finally, knockdown hnRNP K decreased mRNA oscillation in both Dbp and Dbp-dependent clock genes. Taken together, our results show rhythmic protein expression of hnRNP K and provide new insights into its function as a transcriptional amplifier of Dbp. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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