Transforming growth factor-β5 expression during early development of Xenopus laevis

Members of the transforming growth factor-beta (TGF-beta) superfamily play various roles during development in both vertebrates and invertebrates. Two isoforms, TGF-beta 2 and -beta 5, have been isolated from Xenopus laevis. We describe here the localization of TGF-beta 5 mRNA in early embryos of X. laevis, assessed by whole-mount in situ hybridization. The first detectable expression of TGF-beta 5 was seen in the stage 14 embryo at the posterior tip of notochord, which continued to later stages, accompanied by the expression in bilateral regions of posterior wall in the tail region next to the notochord. At later stages, transient expression was seen in the cement gland (around stage 21) and in the somites (stages 24-27). In addition, expression was present in the branchial arches (stage 29-36) and olfactory placodes (stage 36). (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.