[ Research Interests ] [ Representative Publications ]

Steven A. Farber Staff Member Carnegie Institution of Washington Adjunct Associate Professor Department of Biology

Carnegie Institution of Washington     Department of Embryology 3520 San Martin Drive Baltimore, Maryland 21218 Office Telephone: Lab Telephone: Department Fax: Email: (410) 554-8196 (410) 246-3028 (410) 243-6311 Steven A. Farber Carnegie Web Site Carnegie Institution of Washington

Research Interests Work in Dr. Farber's laboratory utilizes the zebrafish, danio rerio, to visualize biochemical processes in living embryos by exploiting their accessibility and optical clarity. The list of cell Localized cPLA2 activity is detected in zebrafish embryos in vivo signaling molecules that are derived from membrane phospholipids is continually growing. Often the synthesis of these molecules requires the activity of phospholipases, enzymes that cleave phospholipids in response to specific cellular signals.Specifically, the Farber laboratory has focused on studying phospholipase A2 (PLA2) activity in the developing embryo. PLA2 activity is unusual in that it releases potent lipid signaling molecules that can act both intracellularly as a second messenger, and extracellularly by binding to specific receptors. Developmental processes where PLA2 signaling exemplifies this dual character are: cell movement (metastasis and integrin/matrix interactions), membrane fusion (sperm acrosomal activation), and oocyte maturation (mediates responses to progesterone). PLA2 signaling has also been implicated in a number of human conditions (i.e. arthritis, septic shock, and cancer) and is known to play a role in neurotransmission. Despite these findings, little is known about the role of PLA2 in cell signaling events important during embryonic development. To facilitate the study of zebrafish phospholipase activity, Dr. Farber developed both a TLC-based assay that allows the quantification and characterization of embryonic PLA2A clutch of live, 5 day post fertilization wild type and fat free mutant zebrafish larvae labeled with a fluorescent reporter of PLA2 activity. activity; and a fluorescence-based biosensor to localize PLA2 activity in living embryos. These assays made it possible to perform a new type of genetic screen for mutations that alter PLA2 activity. An important advantage of the zebrafish is its utility in genetic analyses. The use of genetics may provide a way to identify modifiers of PLA2activity thereby increasing our understanding of its function and regulation. This knowledge will almost certainly inform our understanding of a number of human diseases. PLA2 activity can be regulated post-transcriptionally, and candidates for mediating this regulation are the annexins (ANX), a highly conserved family of Ca2+ and lipid binding proteins that are known to inhibit PLA2. Another goal of the laboratory is to explore the regulatory role of ANXs in zebrafish development. Dr. Farber has cloned a number of zebrafish ANX genes A fluorescent PLA2 reporter results intensely labeled digestive system in 5 day old zebrafish larvae . that are expressed in temporally and spatially distinct patterns during zebrafish development. Work is now focused on positioning these genes on the zebrafish genetic map and screening for mutations that disrupt these genes. Taking advantage of the optical clarity of zebrafish embryos, the Farber laboratory has developed in vivo fluorescent reporters of PLA2 activity to visualize enzymatic activity in developingZebrafish digestive tract labeling following ingestion of NBD embryos. These molecules either change color or become fluorescent when cleaved by lipases. Using one such reporter Dr. Farber was able to observe PLA2 activity at the subcellular level. Furthermore, these molecules can be delivered to older fish to study lipid metabolism in the colon. A long-term goal of the laboratory is to better understand the role of lipid mediators in the normal vertebrate embryo and how they influence intestinal tumor formation. Dr. Farber's research exploits the unique advantages of the zebrafish by coupling genetic analyses to real-time imaging of enzyme function during development. Science Outreach Program We have created a Science Outreach Program (SOP) that incorporates life science and laboratory education using zebrafish. The outreach program brings the zebrafish to grade school classrooms for hands-on experiments. The program teaches students science literacy, genetics, the experimental process and the cardiovascular system through the use of live zebrafish. The mission of the SOP is to foster an enthusiasm for science education, promote interest for future participation in a biology-related field, and allow all students the opportunity to learn life science through a hands-on, student-centered approach to instruction. Some of the goals of the program are to instill in children a love for science and foster knowledge and experience of science education to all students and teachers regardless of community, poverty or race. In the last 2 years we have made substantial progress toward bringing live science education to the community. Currently, the SOP has been teaching our science unit to classes of 2nd, 7th, and 8th grade. Students enjoy a total of 15 hours of live experimentation during the unit. This program has garnered significant excitement among primary school faculty in the region and the scientific press. Since we began, almost 3000 students have participated in our in-class zebrafish unit. (Schaefer, J., and Farber, S. A. (2004) PLoS Biol.) Representative Publications Mulligan T.S., and Farber S.A. (2005) A "Block and Rescue" Pharmacogenetic Approach to Dissecting a Biochemical Pathway Controlling Germ Cell Migration. Zebrafish. 1:343-347. Smart E.J., De Rose R.A., and Farber, S.A.(2004) Annexin II - Caveolin I complex is a target of ezetimibe and regulates intestinal cholesterol transport. PNAS 101:3450-3455. Schaefer, J., and Farber, S. A. (2004) PLoS Biol. In Press. Farber S.A., Pack M., Ho S.Y., Johnson, I.D., Wagner D.S., Dosch R., Mullins M.C., Hendrickson S., Hendrickson E.K., and Halpern M.E. (2001) Analysis of Digestive Physiology Using Fluorescent Phospholipid Reporters. Science. 292:1385-1388. (abstract, full text) Farber, S.A., Olson, E., Clark, J.D. and Halpern M.E. (1999) Characterization of Ca2+ -Dependent Phospholipase A2 Activity During Zebrafish Embryogenesis. J. Biol. Chem. 274:19338-19346. Hendrickson, H.S., Hendrickson, E.K., Johnson, I.D., Farber, S.A. (1999) Intramolecularly quenched BODIPY-labeled phospholipid analogs in phospholipase A2 and platelet-activating factor acetylhydrolase assays and in vivo fluorescence imaging. Anal. Biochem. 276:27-35.

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