Expression of NPR‐B and CNP mRNA during the course of chick embryonic limb development: implication in the regulation of limb mesenchymal chondrogenesis

Abstract

The homodimeric transmembrane receptor natriuretic peptide receptor B (NPR-B) produces cytoplasmic cyclic GMP from GTP on binding its extracellular ligand, C-type natriuretic peptide (CNP). Mutations in the NPR-B gene have shown to be the cause of acromesomelic dysplasia, type Maroteaux (AMDM), an autosomal recessive skeletal dysplasia. This signaling pathway has also been implicated in the regulation of limb mesenchymal chondrogenesis. Thus, the expression profile of both, NPR-B and CNP mRNA, in the process of chick embryonic limb development has been investigated on the basis of RT-PCR. Results showed that NPR-B mRNA was detectable in chick embryonic limb buds at Hamburger and Hamilton (HH) stage 18, followed by a sharp peak at stage 23/24, and a gradual increase in between stages 25 to 35. CNP mRNA, on the other hand, was detectable within the chick embryonic limb buds in between HH stages 18 to 35, without any significant change of pattern. These preliminary results suggest the involvement of this signaling pathway in the process of limb mesenchymal proliferation and chondrogenic differentiation. A potential regulation of this signaling event at the receptor level has to be considered for future studies. (Supported by The Scientific and Technological Research Council of Turkey, Grant number SBAG-104S261).