January 1, 2006;
Vertebrate homologues of Frodo are dynamically expressed during embryonic development in tissues undergoing extensive morphogenetic movements.
has been identified as a protein interacting with Dishevelled
, an essential mediator of the Wnt signaling pathway, critical for the determination of cell fate and polarity in embryonic development. In this study, we use specific gene probes to characterize stage- and tissue
-specific expression patterns of the mouse Frodo
homologue and compare them with Frodo
expression patterns in Xenopus embryos. In situ hybridization analysis of mouse Frodo
transcripts demonstrates that, similar to Xenopus Frodo
, mouse Frodo
is expressed in primitive streak mesoderm
, neural crest, presomitic mesoderm
, and somites
. In many cases, Frodo
expression is confined to tissues undergoing extensive morphogenesis, suggesting that Frodo
may be involved in the regulation of cell shape and motility. Highly conserved dynamic expression patterns of Frodo
homologues indicate a similar function for these proteins in different vertebrates.
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Figure 1. Localization of Frodo transcripts during Xenopus embryogenesis. A,B: Lateral views of stage 10 (A) and stage 10.5 (B) embryos (animal is up; dorsal is to the right), showing Frodo expression in the dorsal mesoderm (DM) and neuroectoderm (NE). Embryos were bisected sagittally before whole-mount in situ hybridization. Black arrowheads point to the dorsal lip (DL). C,D: Dorsal views of stage 14 (C) and stage 18 (D) embryos (anterior is up). Frodo expression is detectable predominantly at the edge and the midline (ML) of the neural plate (NP), a part of the diencephalon (arrowheads), in early neurulae (C) and in neural crest cells (NC) at the late neurula stage (D). A-D: Right panels contain schematic diagrams for each embryo shown. E,F: Lateral views of stage 23 (E) and stage 28 (F) embryos (anterior is to the left). Frodo is expressed in the eyes, branchial arches (BA), and presomitic mesoderm (PSM, arrowhead) at the early tail bud stage (E) and is also detectable in the somites (S, arrows) at the late tail bud (F) stage. G: Lateral view of stage 33 embryo (anterior is to the left), showing Frodo expression in branchial arches (BA), somites (S, arrows), and the tip of the tail (arrowhead). H: A transverse section of stage 18 embryo, counterstained in eosin, shows enriched expression of Frodo in neural crest (NC).