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Ultrasound Imaging of Gene Expression in Mammalian Cells

Farhadi, Arash and Ho, Gabrielle H. and Sawyer, Daniel P. and Bourdeau, Raymond W. and Shapiro, Mikhail G. (2019) Ultrasound Imaging of Gene Expression in Mammalian Cells. . (Unpublished)

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The study of cellular processes occurring inside intact organisms and the development of cell-based diagnostic and therapeutic agents requires methods to visualize cellular functions such as gene expression in deep tissues. Ultrasound is a widely used biomedical technology enabling deep-tissue imaging with high spatial and temporal resolution. However, no genetically encoded molecular reporters are available to connect ultrasound contrast to gene expression in mammalian cells. To address this limitation, we introduce the first mammalian acoustic reporter genes. Starting with an eleven-gene polycistronic gene cluster derived from bacteria, we engineered a eukaryotic genetic program whose introduction into mammalian cells results in the expression of a unique class of intracellular air-filled protein nanostructures called gas vesicles. The scattering of ultrasound by these nanostructures allows mammalian cells to be visualized at volumetric densities below 0.5%, enables the monitoring of dynamic circuit-driven gene expression, and permits high-resolution imaging of gene expression in living animals. These mammalian acoustic reporter genes enable previously impossible approaches to monitoring the location, viability and function of mammalian cells in vivo.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Farhadi, Arash0000-0001-9137-8559
Ho, Gabrielle H.0000-0002-8511-5549
Sawyer, Daniel P.0000-0003-2926-191X
Bourdeau, Raymond W.0000-0003-2202-1980
Shapiro, Mikhail G.0000-0002-0291-4215
Additional Information:The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission. bioRxiv preprint first posted online Mar. 18, 2019. The authors thank David Maresca, Bill Ling and Avinoam Bar-Zion for help with ultrasound imaging, Noushin Koulena for assistance with tissue histology, Andres Collazo for confocal microscopy, Chris Buser and Oak Crest Institute of Science for cell sectioning and staining, Erik Jue and William Chour for assistance with initial experiments. Electron microscopy was performed at the Beckman Institute Resource Center for Transmission Electron Microscopy at Caltech. Fluorescence imaging of tissues was performed in the Biological Imaging Facility of the Caltech Beckman Institute with support from the Arnold and Mabel Beckman Foundation. We appreciate the help of Audrey Lee-Gosselin and Caltech’s Office of Laboratory Animal Research with animal protocols and husbandry. Arash Farhadi was supported by the NSERC graduate fellowship. Daniel Sawyer was supported by the NSF graduate research fellowship (Grant No. 1745301). This research was supported by the National Institutes of Health (grant numbers R01EB018975 and U54CA199090 to M.G.S.), the Heritage Medical Research Institute (M.G.S.), the Packard Fellowship for Science and Engineering (M.G.S.), and the Burroughs Welcome Fund Career Award at the Scientific Interface (M.G.S.). Author Contributions: A.F. and M.G.S. conceived and planned the research. A.F. and G.H.H. performed the experiments. A.F. and R.W.B. designed the DNA sequences. A.F. and D.P.S. designed and optimized the ultrasound imaging sequences. A.F. analyzed data. A.F., and M.G.S. wrote the manuscript with input from all authors. M.G.S. supervised the research. The authors declare no competing financial interests.
Group:Heritage Medical Research Institute
Funding AgencyGrant Number
Arnold and Mabel Beckman FoundationUNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
NSF Graduate Research FellowshipDGE-1745301
Heritage Medical Research InstituteUNSPECIFIED
David and Lucile Packard FoundationUNSPECIFIED
Burroughs Welcome FoundationUNSPECIFIED
Record Number:CaltechAUTHORS:20190319-072910559
Persistent URL:
Official Citation:Ultrasound Imaging of Gene Expression in Mammalian Cells. Arash Farhadi, Gabrielle H. Ho, Daniel P. Sawyer, Raymond W. Bourdeau, Mikhail G. Shapiro. bioRxiv 580647; doi:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:93946
Deposited By: Tony Diaz
Deposited On:19 Mar 2019 15:01
Last Modified:19 Mar 2019 15:01

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