Laminin and integrin expression in the ventral ectodermal ridge of the mouse embryo: Implications for regulation of BMP signalling

PMCID: PMC3629792.[Background]: The ventral ectodermal ridge (VER) is an important signalling centre in the mouse tail-bud following completion of gastrulation. BMP regulation is essential for VER function, but how these signals are transmitted between adjacent tissues is unclear. [Results]: We investigated the idea that extracellular matrix components might be involved, using immunohistochemistry and in situ hybridisation to detect all known α, β, and γ laminin chains and their mRNAs in the early tail bud. We identified an apparently novel laminin variant, comprising α5, β3 and γ2 chains, as a major component of the VER basement membrane at E9.5. Strikingly, only the mRNAs for these chains were co-expressed in VER cells, suggesting that lamin532 may be the sole basement membrane laminin at this stage. Since α6 integrin was also expressed in VER cells, this raises the possibility of cell-matrix interactions regulating BMP signalling at this site of caudal morphogenesis. [Conclusions]: Laminin532 could interact with α6-containing integrin to direct differentiation of the specialised VER cells from surface ectoderm.This work was supported by de Instituto de Salud Carlos III project CP08/00111 and PS09/00050 (to P.Y.-G.), la Consejería de Salud de la Junta de Andalucia project PI-0438-2010 (to P.Y.-G.), and the Wellcome Trust (to A.J.C.).Peer reviewe