个体发育 ontogeny >胚胎发育。 >胚后发育。 0.2-0.15mm POET DVULATORY WEEKS
个体发育 – ontogeny ➢ 胚胎发育。 ➢ 胚后发育
动物发育的主要阶段 受精 桑椹胚→(囊胚)□(原肠胚 成体〈(幼体 器官形成 神经胚 有些动物个体还要经过变态才能发育成为成体。如两 栖类要经历尾部变化、四肢生长和呼吸系统的改变
动物发育的主要阶段 有些动物个体还要经过变态才能发育成为成体。如两 栖类要经历尾部变化、四肢生长和呼吸系统的改变。 受精 桑椹胚 成体 幼体 囊胚 器官形成 原肠胚 神经胚
受精( fertilization >新个体的生命开始于两性 Acrosomal reaction cumulus cell taver 配子—精子和卵子的融二 a pellucida 合,其融合过程称为受精。 eggnudeus conical granule >通过受精激活发育的程序, zona pellucida 受精卵开始胚胎发育
➢ 新个体的生命开始于两性 配子——精子和卵子的融 合，其融合过程称为受精。 ➢ 通过受精激活发育的程序， 受精卵开始胚胎发育。 受精（ fertilization ）
ARTICLE doi:10.1038/ nature12632 Nanog, Pou5fl and SoxBl activate zygotic gene expression during the maternal-to-zygotic transition Miler T Lee*, Ashley R Bonneau*, Carter M. Takacs, Ariel A Bazzini, Kate R DiVito, Elizabeth S. Fleming antonio j. giraldez. 2 After fertilization, maternal factors direct development and trigger zygotic genome activation(ZGA)at the maternal-to- zygotic transition(MZT). In zebrafish, ZGA is required for gastrulation and clearance of maternal messenger RNAs, which is in part regulated by the conserved microRNA miR-430. However, the factors that activate the zygotic program in vertebrates are unknown. Here we show that Nanog, Pou5fl(also called Oct4) and SoxBl regulate zygotic gene acti- vation in zebrafish. We identified several hundred genes directly activated by maternal factors, constituting the first wave of zygotic transcription Ribosome profiling revealed that nanog, sox19b and pou5fl are the most highly translated transcription factors pre-MZT. Combined loss of these factors resulted in developmental arrest before gastrulation and a failure to activate >75% of zygotic genes, including miR-430. Our results demonstrate that maternal Nanog, Pou5fl and SoxBI are required to initiate the zygotic developmental program and induce clearance of the maternal program by activating miR-430 expression
卵裂 受精卵 2细胞期 4细胞期 32细胞期 16细胞期 8细胞期 外胚层 中胚层 内胚层 囊胚期(胚泡) 原肠胚期