Raizen Laboratory
Dr. David Raizen
My research interests are the regulation and function of sleep-like behavior in C. elegans.
Despite the fact that we spend one third of our life sleeping, and despite the fact that all animals appear to sleep, the purpose or sleep remains a mystery. In addition, the molecular basis underlying sleep/wake regulation is poorly understood.
My lab uses C. elegans as a model system to address these questions. C. elegans offers many experimental advantages including powerful genetic tools as well as a simple neuroanatomy.
Growth of C. elegans from an embryo to an adult is punctuated by four molts, during which the animal secretes a new cuticle and sheds its old one. Prior to each molt the worm has a quiescent behavioral state called lethargus. Lethargus has several similarities to sleep including reversibility, increased sensory arousal threshold, and homeostasis, which is manifested by a decreased latency to sleep and an increased depth of sleep following a period of deprivation. We have identified the cGMP dependent protein kinase gene egl-4 as a regulator of sleep like behavior in worms. We are studying how egl-4 acts to promote this worm sleep-like state.
By studying the purpose and genetic regulation of C. elegans lethargus, we hope to identify additional novel sleep regulators, and to gain insight into why sleep and sleep-like states had evolved, a central biological mystery.
Selected Publications
Raizen D (2009) Studies of behavioral quiescnece in the nematode Caenorhabditis elegans in Current Advances in Sleep Biology: Regulation and Function, edited by M. Frank. Hauppage NY: Nova Science Publishers, Inc. In press.
You Yj, Kim J, Raizen DM, Avery L. Insulin, cGMP, and TGF-b Signals Regulate Food Intake and Quiescence in C. elegans: A model for Satiety. Cell Metabolism 2008, 7(3):249-257.
Raizen D,Zimmerman J, Maycock M, Uyen DT, Young-jai Y, Sundaram MV, Pack AI. Lethargus is c. elegans sleep-like state. Nature 2008 Jan 31;451(7178):569-72.
Zimmerman JE, Raizen DM, Maycock MH, Maislin G, Pack AI. A video method to study Drosophila sleep. Sleep 2008, 31(11):1587-1598.
Raizen DM, Cullison KM, Pack AI, Sundaram MV. A novel gain-of-function mutant of the cyclic GMP-dependent protein kinase egl-4 affects multimple physiological processes in Caenorhabditis elegans. Genetics 2006.173(1):177-87.
Positions available
A postdoctoral position is available immediately in the Raizen lab to study the regulation of lethargus in C. elegans. Lethargus is a developmentally-timed quiescence program that has sleep-like behavioral properties. Standard methods in the lab include molecular biology, genetics, transgenesis, cell ablation, and behavioral analysis. Initial appointment is for one year and will be supported on an a grant from the NIH, with anticipation of yearly extensions of up to four years dependent on performance and available funding. Send curriculum vitae, contact information for three references, and a letter describing research experience and the reason for interest in our research to David Raizen.
Student positions (see Penn graduate group: Neuroscience and CAMB)
Student Rotation Projects
- The regulation of quiescence including the role of cAMP and cGMP signaling.
- The relationship between synaptic plasticity, metabolic cycles and lethargus
- Assessing effects of sleep-active drugs on worm behavior.
- Genetic approach to identify egl-4 signaling pathway.
Education
University of Texas at Austin, BA (Biochemistry) 1989
University of Texas Southwestern Medical School, PhD (Neuroscience) 1997
University of Texas Southwestern Medical School, MD (Medicine) 1997
Allan Pack | Nirinjini Naidoo | David Raizen | Sigrid Veasey