第1023回生物科学セミナー
The “mesodermal” gene brachyury regulates ectoderm-endoderm demarcation in a diploblastic animal, the scleractinian coral Acropora digitifera
Dr. Yuuri Yasuoka（Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University (OIST)）
2015年02月05日(木) 13:30-14:30 理学部 2号館 201号室
The T-box transcription factor Brachyury is expressed around the blastopore during gastrulation of almost all metazoan animals. Its functions for mesoderm formation during gastrulation have been energetically studied in vertebrates. However, its fundamental roles around blastopore are poorly understood in other phyla. Here we show that Brachyury regulates germ layer segregation in embryos of the coral Acropora digitifera. Expression analysis of brachyury showed that brachyury expression around the blastopore is positively regulated by Wnt/?-catenin signaling in the ectoderm of coral embryos, indicating that this regulatory axis is highly conserved among eumetazoans. Loss-of-function analysis showed that Brachyury is required for ectoderm development but not for gastrulation movement. Furthermore, genome-wide transcriptome analysis revealed that Brachyury positively and negatively regulate cell differentiation for ectoderm and endoderm, respectively. Our study proposed that the evolutionarily conserved role of Brachyury during gastrulation of animal embryos is germ layer demarcation around the blastopore. The correlation between Brachyury roles for ectoderm-endoderm demarcation in the diploblastic animal and those for mesoderm-ectoderm demarcation in vertebrates opens the possibility that the origin of mesoderm is ectodermal tissues adjacent to the endoderm.
