Live imaging is the requisite tool for studying cell behaviors driving embryonic development and tissue formation. Genetically-encoded reporters expressed under cell type-specific cis-regulatory elements that drive fluorescent protein expression at sufficient levels for visualization in living specimens have become indispensable for these studies. Increasingly dual-color (red-green) imaging is used for studying the coordinate behaviors if two cell populations of interest, identifying and characterizing subsets of within broader cell populations or subcellular features. Many reporters have been generated using green fluorescent protein (GFP) due to its brightness and developmental neutrality. To compliment the large cohort of available GFP reporters that label cellular populations in early mouse embryos, we have generated a red fluorescent protein (RFP)-based transgenic reporter using the red fluorescent tdTomato protein driven by cis-regulatory elements from the mouse Hex locus. The Hex-tdTomato reporter predominantly labels endodermal cells. It is the first RFP reporter of the distal visceral endoderm (DVE)/anterior visceral endoderm (AVE), a migratory population within the early post-implantation embryo. It also labels cells of the definitive endoderm (DE), which emerges at gastrulation. Dual-color visualization of these different early endodermal populations will provide a detailed understanding of the cellular behaviors driving key morphogenetic events involving the endoderm.
- Received February 6, 2017.
- Accepted March 6, 2017.
- © 2017. Published by The Company of Biologists Ltd
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