title: Brachyury-downstream notochord genes and convergent extension in Ciona intestinalis embryos.
abstract: Formation of the chordate body is accomplished by a complex set of morphogenetic movements including convergent extension of notochord cells. In the ascidian Ciona intestinalis, Brachyury plays a key role in the formation of the notochord, and more than 30 Bra-downstream notochord genes have been identified. In the present study, we examined the effects of functional suppression of nine Bra-downstream notochord genes, which include Ci-PTP, Ci-ACL, Ci-prickle, Ci-netrin, Ci-trop, Ci-Noto3, Ci-ASAK, Ci-ERM and Ci-pellino. When the function of the first two genes (Ci-PTP and Ci-ACL) was suppressed with specific morpholinos, the notochord cells failed to converge, while functional suppression of Ci-prickle resulted in a failure of intercalation, and therefore the cells in these three types of embryo remained in the mid-dorsal region of the embryo. Functional suppression of the next four genes (Ci-netrin, Ci-trop, Ci-Noto3 and Ci-ASAK) resulted in the partial defect of intercalation, and the notochord did not consist of a single row. In addition, when the function of the last two genes (Ci-ERM and Ci-pellino) was suppressed, notochord cells failed to elongate in the embryo, even though convergence/extension took place normally. These results indicate that many Bra-downstream notochord genes are involved in convergence/extension of the embryo.
authors.affiliation: Department of Developmental Biology, National Institute for Basic Biology, Okazaki, Aichi 444-8585, Japan.
authors.forename: Kohji
authors.initials: K
authors.lastname: Hotta
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Yamada
authors.forename: Naoto
authors.initials: N
authors.lastname: Ueno
authors.forename: Nori
authors.initials: N
authors.lastname: Satoh
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takahashi
mesh_terms: D000818:Animals; D001483:Base Sequence; D019521:Body Patterning / Q000235:genetics; D002938:Ciona intestinalis / Q000196:embryology* / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D019143:Evolution, Molecular; D005326:Fetal Proteins / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D009672:Notochord / Q000196:embryology* / Q000378:metabolism; D020319:Oligodeoxyribonucleotides, Antisense / Q000235:genetics; D020825:T-Box Domain Proteins / Q000235:genetics*; D000098908:Brachyury Protein
chemical_list: D017931:DNA Primers; D005326:Fetal Proteins; D020319:Oligodeoxyribonucleotides, Antisense; D020825:T-Box Domain Proteins; D000098908:Brachyury Protein