title: Spatial and temporal expression patterns of Xenopus Nkx-2.3 gene in skin epidermis during metamorphosis.
abstract: Using PCR cloning, the mRNA of XNkx-2.3 gene, a Xenopus tinman homologue, was identified in a cDNA library prepared from thyroid hormone (T(3))-treated tadpole skin. Quantitative RT-PCR and RNase Protection Assay confirmed the expression of XNkx-2.3 in adult frog skin and its amount was similar to the amount found in heart. In situ hybridization indicated that XNkx-2.3 was expressed in the frog epidermis. Further analysis of XNkx-2.3 expression patterns demonstrates that it shares great similarities with a 63 kDa keratin, a well-characterized marker for skin maturation, in the following aspects. First, XNkx-2.3 was expressed in tadpole skin during metamorphosis (stages 55-59), but not in pre-metamorphic (stage 54) skin. Secondly, XNkx-2.3 expression in skin responded to T(3) stimulation because it could be precociously induced by T(3) at pre-metamorphic stage, both in tadpoles and in cultures of skin explants. Finally, the T(3)-induced appearance of XNkx-2.3 in head skin occurred earlier and at higher level than that in tail skin. These data suggest that XNkx-2.3 may be an important factor for skin maturation and may also serve as a good marker to indicate the maturation of Xenopus epidermis.
authors.affiliation: Laboratory of Mammalian Genes and Development, National Institute of Child Health and Development, National Institute of Health, 2B211, Bldg. 6B, 9000 Rockville Pike, Bethesda, MD 20892, USA. mach@mail.nih.gov
authors.forename: Chang M
authors.initials: CM
authors.lastname: Ma
mesh_terms: D000818:Animals; D004817:Epidermis / Q000254:growth & development* / Q000378:metabolism; D020869:Gene Expression Profiling; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000096:biosynthesis / Q000235:genetics*; D007814:Larva / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014981:Xenopus; D029867:Xenopus Proteins / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D018398:Homeodomain Proteins; D029867:Xenopus Proteins