title: Expression pattern of annelid Zic in embryonic development of the oligochaete Tubifex tubifex.
abstract: Embryonic expression of a Zic homologue (Ttu-Zic) was examined in the oligochaete annelid Tubifex tubifex. The body plan of T. tubifex is characterized by obvious segmentation in the ectoderm and mesoderm. Ttu-Zic expression is detected in the mesodermal germ band and a subset of micromere descendants. Ttu-Zic is transiently expressed in primary m-blast cells (i.e., founder cells of mesodermal segments) as early as the time of their birth from M teloblasts. During its development, each mesodermal segment experiences two additional phases of Ttu-Zic expression. Ttu-Zic expression in micromere descendants is seen on the anterior surfaces of embryos undergoing teloblastogenesis; subsequently, these cells proliferate to form bilateral clusters, which then become internalized. Finally, clusters of Ttu-Zic-expressing cells are found in the center of the prostomium, corresponding to the cerebral ganglion. The Ttu-Zic expression profile in the early embryogenesis of T. tubifex may be homologous to those of evolutionarily distant animals.
authors.affiliation: Laboratory for Behavioral and Developmental Disorders, RIKEN Brain Science Institute, Wako, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Takahashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Shimizu
authors.forename: Jun
authors.initials: J
authors.lastname: Aruga
mesh_terms: D000818:Animals; D000845:Annelida / Q000196:embryology* / Q000235:genetics*; D001921:Brain / Q000196:embryology / Q000378:metabolism; D019070:Cell Lineage; D004625:Embryo, Nonmammalian / Q000378:metabolism; D047108:Embryonic Development / Q000235:genetics*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D050437:Genes, Developmental; D008648:Mesoderm / Q000166:cytology / Q000378:metabolism