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Department of

Pharmacology & Systems Physiology 

Photo of  Christian Hong, PhD

Christian Hong, PhD

Associate Professor

Research Interests

Our lab is interested in the molecular mechanism of circadian rhythms and its functional role in cell cycle controls. Circadian rhythms are periodic physiological events that recur about every 24 hours. The importance of circadian rhythms is well recognized in many different organisms’ survival as well as in human physiology. Misregulation in circadian rhythms may lead to different conditions such as depression, familial advanced sleep phase syndrome (FASPS), delayed sleep phase syndrome (DSPS), and/or insomnia, which largely impact our society. Recent studies indicate higher incidents of cancer in clock defective mice and chronic jet-lag is associated with higher mortality rate in aged mice. The cell cycle control is intertwined with circadian network via molecular coupling factors such as WEE1, a kinase that is involved in G2 to M transition. Therefore, maintaining robust circadian rhythms is vital for the health of an organism. Circadian rhythms are dictated by cellular regulations of transcriptional and translational feedback loops. There are positive and negative elements that create a time-delayed negative feedback loop to generate a rhythm of about 24 hours. Several core clock components oscillate in terms of their quality and abundance, and determine the period and the phase of the circadian clock. We use mathematical models and tools in genetics and molecular biology to investigate molecular components and dynamical properties of circadian rhythms and cell cycle in a model organism, Neurospora crassa. Neurospora is a filamentous fungus that provides excellent tools for circadian rhythms research. We follow molecular rhythms in real-time with bioluminescence assay utilizing luciferase derived from firefly luciferase. We can track gene regulations or protein abundances as a function of time with bioluminescence assay. This provides a good handle for us to study dynamical properties of circadian rhythms and cell cycle in various genetic backgrounds. Hypotheses are derived from mathematical simulations and predictions are experimentally validated. This interdisciplinary approach creates a synergy to efficiently understand nuts and bolts of circadian rhythms and its roles in cell cycle control.

  • PhD: Virginia Tech
  • BS: Virginia Tech
  • MS: Virginia Tech
Contact Information
  • Medical Sciences Building
  • Room 4201
  • 231 Albert Sabin Way
  • Cincinnati, Ohio 45267-0576
  • Office 513-558-5093
  • Fax 513-558-5738
  • Email

Peer Reviewed Publications

Caicedo-Casso, Angélica; Kang, Hye-Won; Lim, Sookkyung; Hong, Christian I 2015. Robustness and period sensitivity analysis of minimal models for biochemical oscillators. Scientific reports, 5 , 13161

Chen, Shuang; Brunskill, Eric W; Potter, S Steven; Dexheimer, Phillip J; Salomonis, Nathan; Aronow, Bruce J; Hong, Christian I; Zhang, Tongli; Kopan, Raphael 2015. Intrinsic Age-Dependent Changes and Cell-Cell Contacts Regulate Nephron Progenitor Lifespan. Developmental cell, 35 1, 49-62

Cockrell, Allison L; Pirlo, Russell K; Babson, David M; Cusick, Kathleen D; Soto, Carissa M; Petersen, Emily R; Davis, Miah J; Hong, Christian I; Lee, Kwangwon; Fitzgerald, Lisa A; Biffinger, Justin C 2015. Suppressing the Neurospora crassa circadian clock while maintaining light responsiveness in continuous stirred tank reactors. Scientific reports, 5 , 10691

Dovzhenok, Andrey A; Baek, Mokryun; Lim, Sookkyung; Hong, Christian I 2015. Mathematical modeling and validation of glucose compensation of the neurospora circadian clock. Biophysical journal, 108 7, 1830-9

Hong, Christian I; Zámborszky, Judit; Baek, Mokryun; Labiscsak, Laszlo; Ju, Kyungsu; Lee, Hyeyeong; Larrondo, Luis F; Goity, Alejandra; Chong, Hin Siong; Belden, William J; Csikász-Nagy, Attila 2014. Circadian rhythms synchronize mitosis in Neurospora crassa. Proceedings of the National Academy of Sciences of the United States of America, 111 4, 1397-402

Moore, Sean R; Pruszka, Jill; Vallance, Jefferson; Aihara, Eitaro; Matsuura, Toru; Montrose, Marshall H; Shroyer, Noah F; Hong, Christian I 2014. Robust circadian rhythms in organoid cultures from PERIOD2::LUCIFERASE mouse small intestine. Disease models & mechanisms, 7 9, 1123-30

Zámborszky, Judit; Csikász-Nagy, Attila; Hong, Christian I 2014. Neurospora crassa as a model organism to explore the interconnected network of the cell cycle and the circadian clock. Fungal genetics and biology : FG & B, 71 , 52-7

Lee, Kang Kug; Ahn, Chong H; Hong, Christian I 2013. Circadian rhythms in Neurospora crassa on a polydimethylsiloxane microfluidic device for real-time gas perturbations. Biomicrofluidics, 7 4, 44129

Hong, Christian I; Zámborszky, Judit; Csikász-Nagy, Attila 2009. Minimum criteria for DNA damage-induced phase advances in circadian rhythms. PLoS computational biology, 5 5, e1000384

Hong, Christian I; Jolma, Ingunn W; Loros, Jennifer J; Dunlap, Jay C; Ruoff, Peter 2008. Simulating dark expressions and interactions of frq and wc-1 in the Neurospora circadian clock. Biophysical journal, 94 4, 1221-32

Dunlap, J C; Loros, J J; Colot, H V; Mehra, A; Belden, W J; Shi, M; Hong, C I; Larrondo, L F; Baker, C L; Chen, C-H; Schwerdtfeger, C; Collopy, P D; Gamsby, J J; Lambreghts, R 2007. A circadian clock in Neurospora: how genes and proteins cooperate to produce a sustained, entrainable, and compensated biological oscillator with a period of about a day. Cold Spring Harbor symposia on quantitative biology, 72 , 57-68

Hong, Christian I; Conrad, Emery D; Tyson, John J 2007. A proposal for robust temperature compensation of circadian rhythms. Proceedings of the National Academy of Sciences of the United States of America, 104 4, 1195-200

Loros, J J; Dunlap, J C; Larrondo, L F; Shi, M; Belden, W J; Gooch, V D; Chen, C-H; Baker, C L; Mehra, A; Colot, H V; Schwerdtfeger, C; Lambreghts, R; Collopy, P D; Gamsby, J J; Hong, C I 2007. Circadian output, input, and intracellular oscillators: insights into the circadian systems of single cells. Cold Spring Harbor symposia on quantitative biology, 72 , 201-14

Zámborszky, Judit; Hong, Christian I; Csikász Nagy, Attila 2007. Computational analysis of mammalian cell division gated by a circadian clock: quantized cell cycles and cell size control. Journal of biological rhythms, 22 6, 542-53

Mehra, Arun; Hong, Christian I; Shi, Mi; Loros, Jennifer J; Dunlap, Jay C; Ruoff, Peter 2006. Circadian rhythmicity by autocatalysis. PLoS computational biology, 2 7, e96

Tyson, J J; Hong, C I; Thron, C D; Novak, B 1999. A simple model of circadian rhythms based on dimerization and proteolysis of PER and TIM. Biophysical journal, 77 5, 2411-7