Developmental Biology 斑马鱼神经管的形成 neural plate spider neural tube
Developmental Biology 斑马鱼神经管的形成
Developmental Biology 、神经诱导作用 Blastocoel 1. Organizer mesoderm 诱导神经管的形成 两栖动物胚胎胚孔背唇诱 Presumptive Primary blaster modern nc导第二胚轴形成的作用叫做 Induced secondary structures Primary structures primary embryonic induction Somite Lumen of gut Notochord Somite Endoderm dcoe) Neural tube Figure 15.12 Self-differentiation of the dorsal blastopore lip tissue. (A)Dorsal blastopore lip from early gastrula is transplanted into another early gastrula in the region that normally becomes ventral epidermis. (B)Tissue invaginates and forms a second archenteron and then a second embryonic axis. both donor and host tissues are seen in the new neural tube, notochord, and somites. (C)Eventually, a second embryo forms that is joined to the host
Developmental Biology 1.Organizer mesoderm 诱导神经管的形成 两栖动物胚胎胚孔背唇诱 导第二胚轴形成的作用叫做 primary embryonic induction 二、神经诱导作用
Developmental Biology 主要胚胎诱导作用也存在于其它物种上 鸭的 Hensen` s node移植到鸡胚上诱导一个次级胚轴形成 (A) Induced Transplantation of neural tube embryo duck Hensens node Duck embryo Chick embryo Figure 15. 13 Induction of a new embryonic axis by Hensen's node (A)Hensens node tissue is removed from a duck embryo and implanted into a host chick embryo. (B)An accessory neural tube is induced at the graft site.(After Waddington, 1933.)
Developmental Biology 主要胚胎诱导作用也存在于其它物种上 鸭的Hensen`s node移植到鸡胚上诱导一个次级胚轴形成
Developmental Biology Animal E mbryonIc Er mbryonIc shield shie 斑 Ventral Dorsal Donor Host 组马 Vegetal 织鱼 中的 Figure 11.5 The embryonic shield as organizer in the fish embryo. a donor embryonic 心胚 shield (about 100 cells from a stained embryo) is transplanted into a host em- 活盾 bryo at the same early-gastrula stage The result is two embryonic axes joined 性具 to the host's yolk cell. In the photo- graph, both axes have been stained for 有 sonic hedgehog mRNA, which is ex pressed in the ventral midline. (The embryo to the right is the secondary axis. )(After Shinya et al. 1999; photo graph courtesy of the authors
Developmental Biology 斑马鱼的胚盾具有 组织中心活性
Developmental Biolo Animal epe Neural ectoderm ectoderm Ventral Dorsal ORGANIZER MOLECULES BMP4 Chordin, Noggin, Mesoderm Follistatin Xnr3 神经诱导作用的机制 Dorsal endoderm Vegetal 组织中心产生的信号分子(如 Chordin、 Noggin、 Follistatin)可 BMP7 screw 拮抗腹部化信号(如BMP4),从而 使其附近的外胚层细胞朝预置的 Non-neural homeobox gen 神经命运发育 Short gastrulation B Chordates 口 Drosophila gure 15.23 Model for the action of the organizer.(A)BMP4(and certain other molecules)are powerful ventralizing factors. Organizer proteins such as Chordin and Noggin may block the action of BMP4( Follistatin may inhibit the action of BMP7, which com with BMP4 to activate it. The antagonistic effects of these proteins can be in all three germ layers.(B)Homologous developmental pathways in the for mation of the central nervous systems of a vertebrate(Xenopus) and an invertebrate (Drosophila). The vertebrate factor is in black, the homologous Drosophila protein is in color. (After De Robertis and Sasai, 1996; Sasai et al., 1996.)
Developmental Biology 神经诱导作用的机制 组织中心产生的信号分子(如 Chordin、Noggin、Follistatin)可 拮抗腹部化信号(如BMP4)，从而 使其附近的外胚层细胞朝预置的 神经命运发育