title: Patterns of gene expression in the core of Spemann's organizer and activin-treated ectoderm in Cynops pyrrhogaster.
abstract: The presumptive pharyngeal endoderm region of the Cynops early gastrula induces head or trunk-tail structures in sandwich culture. Activin-treated ectoderm can mimic this phenomenon at least at the histological level. The patterns of expression of organizer-specific genes were examined to compare these two inductive materials at the molecular level. A chordin cDNA clone from Cynops pyrrhogaster (Cychd) was isolated by reverse transcription-polymerase chain reaction (RT-PCR). Cychd mRNA was first detected in the presumptive pharyngeal endoderm and prechordal plate regions of stage 11 embryos, and was expressed continuously until stage 20. The spatiotemporal expression pattern of Cychd was similar to that of Xenopus chordin. The patterns of expression of organizer-related genes in the pharyngeal endoderm and activin-treated ectoderm were compared by RT-PCR analysis. Expression of Cychd in these two materials peaked at the time when they can induce head structures in sandwich culture. Expression of fork head and goosecoid did not change in the presumptive pharyngeal endoderm over this period. Cychd may play a key role in head formation in the Cynops embryo.
authors.affiliation: Department of Life Sciences (Biology), Graduate School of Arts and Sciences, The University of Tokyo, Japan.
authors.forename: C
authors.initials: C
authors.lastname: Yokota
authors.forename: T
authors.initials: T
authors.lastname: Ariizumi
authors.forename: M
authors.initials: M
authors.lastname: Asashima
mesh_terms: D028341:Activins; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004475:Ectoderm / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000737:chemistry / Q000378:metabolism; D004707:Endoderm / Q000737:chemistry / Q000378:metabolism; D005775:Gastrula / Q000737:chemistry / Q000378:metabolism*; D015870:Gene Expression / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D005796:Genes / Q000235:genetics; D006023:Glycoproteins / Q000235:genetics; D007265:Inhibins / Q000494:pharmacology*; D036341:Intercellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D010614:Pharynx / Q000737:chemistry / Q000196:embryology / Q000378:metabolism; D012455:Salamandridae / Q000196:embryology* / Q000235:genetics*; D012680:Sensitivity and Specificity
chemical_list: D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D028341:Activins; D007265:Inhibins; C054234:chordin