Ephs and ephrins during early stages of chick embryogenesis

Abstract

The Eph family of receptor tyrosine kinases and their ligands, the ephrins, are membrane-bound proteins that mediate bidirectional signals between adjacent cells. By modulating cytoskeleton dynamics affecting cell motility and adhesion, Ephs and ephrins orchestrate cell movements during multiple morphogenetic processes, including gastrulation, segmentation, angiogenesis, axonal pathfinding, and neural crest cell migration. The full repertoire of developmental Eph/ephrin functions remains uncertain, however, because coexpression of multiple receptor and ligand family members, and promiscuous interactions between them, can result in functional redundancy. A complete understanding of expression patterns, therefore, is a necessary prerequisite to understanding function. Here, we present a comprehensive expression overview for 10 Eph and ephrin genes during the first 48 hr of chick embryo development. First, dynamic expression domains are described for each gene between Hamburger and Hamilton stages 4 and 12; second, comparative analyses are presented of Eph/ephrin expression patterns in the primitive streak, the somites, the vasculature, and the brain. Complex spatially and temporally dynamic expression patterns are revealed that suggest novel functions for Eph and ephrin family members in both known and previously unrecognized processes. This study will provide a valuable resource for further experimental investigations of Eph and ephrin functions during early embryonic development.

Eph/ephrin interactions modulate muscle satellite cell motility and patterning

“…Eph receptors are the largest family of mammalian receptor tyrosine kinases; both Eph receptors and their ligands (ephrins) are expressed by almost all tissues in the developing embryo (Baker and Antin, 2003). Eph receptors have also been shown to interact functionally with multiple other transmembrane receptors including Fgfrs, Cxcr4, integrins and cadherins (reviewed by Arvanitis and Davy, 2008).…”

Subdivisions of chick diencephalic roof plate: Implication in the formation of the posterior commissure

“…The different axonal behaviors in the midline suggest that in this place the cells of the MDRP may secrete other guidance signal, different to SCO-spondin, which the axons required to decide if they have to cross or not the midline. In this context it has been described the presence of EphrA7 (Araujo and Nieto, 1997;Marin et al, 2001;Baker and Antin, 2003;Garcia-Calero et al, 2006) and semaphorin 3D (Bao and Jin, 2006) in diencephalic roof plate, although the precise location (lateral or medial) and the function of these molecules in PC development are unknown.…”

Leiomodin-2 is an antagonist of tropomodulin-1 at the pointed end of the thin filaments in cardiac muscle

“…Embryos were rinsed in PBT to stop the digestion, and were then transferred to prehybridization solution. Antisense probe preparation and in situ hybridization was carried out as described (Nieto et al, 1996;Baker and Antin, 2003). Additional images showing Tmod1 and Lmod2 expression were deposited in http://geisha.arizona.edu.…”