Int. J. Dev. Biol. 56: 719 - 728 (2012)
doi: 10.1387/ijdb.120021rw
© UPV/EHU Press

Roles of EphB3/ephrin-B1 in feather morphogenesis

Sanong Suksaweang1,3, Ting-Xin Jiang1, Paul Roybal2, Cheng-Ming Chuong*,1 and Randall Widelitz*,1

1Department of Pathology, 2Department of Biochemistry, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA and 3Department of Pathology and Laboratory Medicine, Institute of Medicine, Suranaree University of Technology, Nakhon Ratchasima, Thailand

ABSTRACT The ephrin receptor (Eph) tyrosine kinases and their ephrin ligands are involved in morphogenesis during organ formation. We studied their role in feather morphogenesis, focusing on ephrin-B1 and its receptor EphB3. Early in feather development, ephrin-B1 mRNA and protein were found to be expressed in the dermal condensation, but not in the inter-bud mesenchyme. Later, in feather buds, expression was found in both the epithelium and mesenchyme. In the feather follicle, ephrin-B1 protein expression was found to be enriched in the feather filament epithelium and in the marginal plate which sets the boundary between the barb ridges. EphB3 mRNA was also expressed in epithelia. In the feather bud, its expression was restricted to the posterior bud. In the follicle, its expression formed a circle at the bud base which may set the boundary between bud and inter-bud domains. Perturbation with ephrin-B1/Fc altered feather primordia segregation and feather bud elongation. Analyses revealed that ephrin-B1/Fc caused three types of changes: blurred placode boundaries with loose dermal condensations, incomplete follicle invagination with less compact dermal papillae, and aberrant barb ridge patterning in feather filament morphogenesis. Thus, while ephrin-B1 suppression does not inhibit the initial emergence of a new epithelial domain, Eph/ephrin-B1 interaction is required for its proper completion. Consequently, we propose that interaction between ephrin-B1 and its receptor is involved in boundary stabilization during feather morphogenesis.

Keywords:

skin appendage development, boundary formation, border formation

*Corresponding author e-mail: widelitz@usc.edu; cmchuong@usc.edu