• activin;
  • paired-related homeobox genes;
  • prx-1;
  • Xenopus laevis

Homeobox genes are expressed both temporally and spatially during vertebrate development, and regulate the tissue-specific expression of other genes. A Xenopus paired-related homeobox-1 (Xprx-1) cDNA was cloned. Xprx-1 had a paired-related homeodomain, but did not contain a paired-box. The sequence of Xprx-1 had a high level of homology with K-2(mouse) and Prx-1(chicken), thus Xprx-1 is assumed to be the Xenopus homolog of these genes. Xprx-1 transcripts were maternally restricted, in Xenopus embryos, and a decrease in the late blastula stage was followed by an increase in zygotic transcripts after gastrulation. The transcripts were localized to the animal hemisphere of the late blastula and were concentrated in the branchial arches of the tail-bud stage embryo. In animal cap experiments, Activin A dose-dependently induced Xprx-1 gene expression. These results suggest that Xprx-1 plays a role in early Xenopus development similar to other species.