Coding sequence and expression patterns of mouse chordin and mapping of the cognate mouse chrd and human CHRD genes

Chordin is a key developmental protein that dorsalizes early vertebrate embryonic tissues by binding to ventralizing TGF-beta-like bone morphogenetic proteins and sequestering them in latent complexes. Here we report the first characterization of mammalian chordin. The full-length cDNA sequence for mouse chordin is given, and RNA blot analysis shows the murine chordin gene Chrd to be expressed at relatively high levels in 7-day postcoitum mouse embryos and at much decreased levels at later developmental times and in adult tissues. These results imply a major role for chordin during gastrulation of the mammalian embryo. Nevertheless, both murine and human chordin genes are shown to be expressed at readily detectable levels in several fetal and adult tissues, most notably liver and cerebellum, suggesting additional roles in organogenesis and homeostasis. Chrd was mapped to mouse chromosome 16 using interspecific crosses, and the cognate human gene CHRD was localized to human chromosome 3q27 by radiation hybrid mapping.