Current MembersGroup Photo (July 2014)
Amita Sehgal, Ph.D.
School of Medicine Bio
John Herr Musser Professor of Neuroscience
10-136 Smilow Center for Translational Research
Howard Hughes Medical Institute/Department of Neuroscience Perelman School of Medicine at the University of Pennsylvania
3400 Civic Center Boulevard Building 421
Philadelphia, PA 19104-6058
Lei Bai, Ph.D.
Annika Barber, Ph.D.
Sleep is controlled by the sum of input from two systems: the circadian system, which drives a 24 h sleep rhythm and the homeostatic system, which signals the need to sleep after prolonged wakefulness. How circadian and homeostatic information are integrated to control sleep is unknown. My research focuses on identifying and mapping brain regions that receive input from both the circadian and sleep homeostatic systems. To identify such brain regions, I use Drosophila genetics and behavioral assays. I then want to tease apart the connectivity between regions of interest, for which I use further behavioral genetics experiments, patch clamp electrophsyiology, calcium imaging and computer modeling.
Paula Haynes, Ph.D.
Katarina Moravcevic, Ph.D.
My research in the lab focuses on two independent projects:I am interested in uncovering molecular underpinnings of sleep homeostasis using Drosophila as a model organism and understanding the interactions between clock proteins utilizing biophysical approaches. In collaboration with Christine Dubowy, we have conducted a thermogenetic screen for mutant fly lines that do not recover sleep following sleep deprivation i.e lines that do not show sleep rebound which is a hallmark of sleep homeostasis. We are now focused on mapping the phenotype of a fly line that is a rebound mutant utilizing modern sequencing approaches. At the same time, since very little is known about the interactions between clock proteins on an atomic level, my efforts are also focused on determining x-ray crystal structures of several key clock protein complexes.
Mi Shi, Ph.D.
Hirofumi Toda, Ph.D.
Shirley Zhang, Ph.D.
Xiangzhong (Sam) Zheng, Ph.D.
Research Assistant Professor
I find the question of why we sleep one of the most compelling mysteries in science. My research seeks to shed some light on this topic by investigating the molecular mechanisms through which short-term and long-term sleep deprivation affect behavior. After a single night of sleep deprivation, flies (like humans) rebound by sleeping longer and more deeply. To elucidate the mechanisms that drive this homeostatic regulation, Katarina Moravcevic and I recently completed a largescale, unbiased genetic screen to identify mutant Drosophila that do not rebound after being sleep deprived. We are currently using molecular and genetic approaches to characterize hits from this screen. I am also interested in the impairment of other behaviors after chronic sleep deprivation. I am working to develop a model behavior negatively affected by chronic sleep loss in flies, which can then be used to identify genes and molecules that promote resilience to sleep deprivation.
I study mechanisms that set the pace of the Drosophila circadian clock. The goal of my research is to uncover novel molecular components that regulate PERIOD (PER) stability and its nuclear entry, and to investigate how post-translational modifications of PER regulate the overall periodicity of circadian rhythms.