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Faculty Members: 
Xiangzhong (Sam) Zheng, Ph.D
Research Assistant Professor of Neuroscience
Member, Institute for Diabetes, Obesity & Metabolism
Department: Neuroscience
Contact information
Department of Neuroscience
University of Pennsylvania School of Medicine
10-142 TRC
3400 Civic Center Blvd
Philadelphia, PA 19104
University of Pennsylvania School of Medicine
10-142 TRC
3400 Civic Center Blvd
Philadelphia, PA 19104
Office: 215-573-2226
Email:
zhengx@mail.med.upenn.edu
zhengx@mail.med.upenn.edu
Education:
B.S. (Biology)
Hangzhou Normal College, 1993.
M.S. (Ecology)
East China Normal University, 1996.
Ph.D. (Genetics)
Institute of Genetics, Fudan University, 1999.
B.S. (Biology)
Hangzhou Normal College, 1993.
M.S. (Ecology)
East China Normal University, 1996.
Ph.D. (Genetics)
Institute of Genetics, Fudan University, 1999.
Post-Graduate Training
Research Associate, Howard Hughes Medical Institute, Department of Neuroscience, University of Pennsylvania School of Medicine, 1999-2005.
Permanent linkResearch Associate, Howard Hughes Medical Institute, Department of Neuroscience, University of Pennsylvania School of Medicine, 1999-2005.
Description of Research Expertise
Research InterestOrganization of the circadian clock and its interaction with the cellular environment
Keywords: Drosophila, circadian clock, metabolism, redox, aging, light entrainment
Circadian behavior is driven by an endogenous molecular oscillator and its output signals. In the fruit fly Drosophila melanogaster, the core molecular circadian clock consists of four major components: CLK, CYC, PER and TIM. Rhythmic inhibition of CLK-CYC transcriptional activity by the temporal expression of PER-TIM complex generates rhythmic gene transcription. It's still largely unknown as how this core oscillator regulates fundamental physiological processes, such as sleep and energy metabolism, and how it integrates with the cellular environment.
My research focuses on the determination of mechanisms underlying circadian regulation of energy metabolism, and identification of cellular/environmental conditions that feed into the circadian clock circuitry.
Selected Publications
Zheng X, Sehgal A: AKT and TOR Signaling Set the Pace of the Circadian Pacemaker. Current Biology 20(13): 1203-1208, 2010.Zheng X*, Koh K*, Sowcik M, Smith CJ, Chen D, Wu MN, Sehgal A : An isoform-specific mutant reveals a role of PDP1ε in the circadian oscillator. Journal of Neuroscience 29(35): 10920-10927, 2009 Notes: *co-first author.
Xu K, Zheng X, Sehgal A: Regulation of Feeding and Metabolism by Neuronal and Peripheral Clocks in Drosophila. Cell Metabolism 8: 289-300, 2008.
Sathyanarayanan S*, Zheng X*, Kumar S, Chen C-H, Chen D, Hay B, and Sehgal A: Identification of novel genes involved in light-dependent CRY degradation through a genome-wide RNAi screen. Genes & Development 22: 1522-1533, 2008 Notes: *Co-first author.
Zheng X, Sehgal A: Probing the relative importance of molecular oscillations in the circadian clock. Genetics 178(3): 1147-55, 2008.
Zheng X, Yang Z, Yue Z, Alvarez JD, Sehgal A: FOXO and insulin signaling regulate the sensitivity of circadian clock to oxidative stress. Proceedings of the National Academy of Sciences 104(40): 15899-904, 2007.
Koh K, Zheng X, Sehgal A : JETLAG resets the Drosophila circadian clock by promoting light-induced degradation of TIMELESS. Science 23(312 ): 1809-12, 2006.
Yuan Q, Lin F.J, Zheng X, Sehgal A: Serotonin modulates circadian entrainment in Drosophila. Neuron 47(1): 115-27, 2005.
Sathyanarayanan S, Zheng X, Xiao R, Sehgal A: Posttranslational regulation of Drosophila PERIOD protein by protein phosphatase 2A. Cell 116: 603-615, 2004.
Jaramillo AM*, Zheng X*, Zhou Y, Amado DA, Sheldon A, Sehgal A, Levitan IB: Pattern of distribution and cycling of SLOB, Slowpoke channel binding protein, in Drosophila. BMC Neuroscience 5: 3, 2004 Notes: *Co-first author.
