Zebrafish Metabolic Disease Reporters – mCherry and eGFP
NIGHTSEA recently visited Dr. Jessica Dunleavey at the Zaghloul Lab at the University of Maryland Baltimore to determine whether our Model SFA Stereo Microscope Fluorescence Adapter system could be used to screen their transgenic zebrafish. The research group investigates the functions of genes associated with metabolic diseases including diabetes, obesity, and NAFLD/NASH (nonalcoholic fatty liver disease / nonalcoholic steatohepatitis). Insulin-producing β (beta) cells occur in islets in the pancreas and are critically important in maintaining glucose levels. They are a significant study topic in the metabolic disease community, and zebrafish β cells are similar to those in mammals both functionally and developmentally. At the stage of larval development we looked at, Dr. Dunleavey estimated that the islet contained approximately 35 β cells. The zebrafish model expresses two fluorescent reporters – eGFP in the exocrine pancreas and mCherry in the β cells (ptf1a:eGFP and ins:mCherry, also known as exocrine eGFP and β cell mCherry) – and Dr. Dunleavey hoped to be able to see both of them.
The test was successful. The images below were made quickly with an iPhone hand-held over the eyepiece of a Nikon SMZ1000 stereo microscope outfitted with the NIGHTSEA SFA. The Royal Blue excitation/emission set was used for imaging eGFP, and the Green set for imaging mCherry.
(Click image for larger view)
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- Zebrafish, white light
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- Zebrafish, showing exocrine eGFP under Royal Blue excitation
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- Zebrafish, showing beta cell mCherry under Green excitation
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- Zebrafish, white light
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- Zebrafish, showing exocrine eGFP under Royal Blue excitation
Acknowledgments – Thanks to Drs. Jessica Dunleavey and Norann Zaghloul for the opportunity to test our system with their zebrafish. The transgenic zebrafish line expressing both ptf1a:eGFP and ins:mCherry was created by Drs. Steven Leach (Dartmouth College) and Michael Parsons (University of California, Irvine).
Pisharath, H., Rhee, J. M., Swanson, M. A., Leach, S. D., & Parsons, M. J. (2007). Targeted ablation of beta cells in the embryonic zebrafish pancreas using E.coli nitroreductase. Mechanisms of Development, 124(3), 218–229. http://doi.org/10.1016/j.mod.2006.11.005
Park, S. W., Davison, J. M., Rhee, J., Hruban, R. H., Maitra, A., & Leach, S. D. (2008). Oncogenic KRAS induces progenitor cell expansion and malignant transformation in zebrafish exocrine pancreas. Gastroenterology, 134(7), 2080–2090. http://doi.org/10.1053/j.gastro.2008.02.084