Hai-Ying Mary Cheng
Assistant Professor

Degrees:

B.Sc. (hons) University of Calgary, 1996
M.Sc. University of Toronto, 1999
Ph.D. University of Toronto, 2003
Post-doctoral fellow, University of Toronto and The Ohio State University, 2003-2007

Research Projects

All organisms have biological clocks, which drive and coordinate circadian rhythms in behaviour and physiology in accordance with the demands of our 24-hour world. In mammals, the master biological clock resides in the suprachiasmatic nuclei (SCN) of the hypothalamus. The SCN has endogenous pacemaker activity that runs at near-24-hour cycles and is regulated by the environmental light cycle, thereby allowing the organism to synchronize its internal clock timing mechanism with daily and seasonal variations in the day/night cycle. Many of us are familiar with the adverse effects of a disrupted biological clock—as a result of environmental conditions (eg., jet lag, night-shift work), or , for the more unfortunate, genetic inheritance (eg., familial advanced sleep phase disorder) and disease (eg., cancer, bipolar disorder). While genetic studies have established that the circadian clock is comprised of a set of ‘core’ clock proteins that interact in interlocking transcription/translation feedback loops to drive rhythms in their own gene expression, our knowledge of the regulatory processes that feed into this molecular clock remains nebulous. Which cascades of cellular events are needed to couple environmental light to the molecular clock? How do individual clock cells synchronize with each other to produce an ensemble rhythm in a tissue? How does aberrant regulation of the circadian clock impact on other biological clocks such as the one controlling cell division? The overall objective of our laboratory is to elucidate the cellular mechanisms that regulate biological timing in mammals, and, in turn, to understand how these cellular mechanisms manifest themselves at the “organism” scale such as animal behaviour, and play a role in diseases arising from their abnormal functioning.

Selected Publications: