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非洲爪蟾个体早期发育Early development of Xenopus laevis

2026-06-25 · 研究进展Research

爪蟾个体发育阶段

非洲爪蟾个体早期发育：卵 → 蝌蚪 → 变态 → 成蛙Xenopus development: egg → tadpole → metamorphosis → adult

非洲爪蟾（Xenopus laevis）体外受精、胚胎数量大、发育迅速且相对透明，是研究脊椎动物早期发育的经典模式动物，对脊椎动物早期胚胎发育研究做出了重要贡献。其发育时期通常采用 Nieuwkoop–Faber（NF）分期系统进行标准化描述。With external fertilization, large clutches and rapid, relatively transparent development, Xenopus laevis is a classic model for vertebrate early development. Stages are standardized using the Nieuwkoop–Faber (NF) system.

早期发育主要阶段Major early developmental stages

1. 卵裂（Cleavage）1. Cleavage

受精后，合子经历完全两侧对称型卵裂。第一次卵裂沟为经裂（meridional），第二次同为经裂且与第一次垂直，第三次为纬裂（latitudinal）。由于植物极富含卵黄，动物极形成较小的卵裂球，植物极形成较大的富含卵黄的卵裂球，产生明显的不等裂格局。After fertilization, the zygote undergoes complete bilateral cleavage. The first cleavage furrow is meridional; the second is also meridional but perpendicular to the first; the third is latitudinal. Yolk-rich vegetal cells divide more slowly, producing smaller animal-pole and larger vegetal-pole blastomeres.

2. 囊胚（Blastula，NF 7–9）2. Blastula (NF 7–9)

约 128 细胞期，胚胎内部形成明显的囊胚腔（blastocoel）。动物极形成小而分裂迅速的细胞，植物极为大型富含卵黄的细胞。晚囊胚期（NF 8–9）启动中囊胚转换（mid-blastula transition，MBT），合子基因组开始转录激活，细胞周期延长并出现不同步。Around the 128-cell stage a distinct blastocoel forms. Animal-pole cells divide rapidly, while vegetal-pole cells remain large and yolk-laden. The mid-blastula transition (MBT, NF 8–9) marks onset of zygotic transcription, cell-cycle lengthening and asynchrony.

3. 原肠胚（Gastrula，NF 10–12）3. Gastrula (NF 10–12)

推定内胚层细胞向内卷折，在植物极背侧形成狭缝状的胚孔（blastopore）。瓶状细胞（bottle cells）收缩并牵引边缘带细胞内移，最终建立内、中、外三个胚层，并确立背腹与前后体轴。Spemann-Mangold 组织者（organizer）分泌 Chordin、Noggin 等信号分子，拮抗 BMP 通路，诱导背侧中胚层与神经组织。Presumptive endoderm involutes to form a slit-like blastopore on the dorsal vegetal side. Bottle cells constrict and drive internalization of marginal-zone cells, ultimately establishing three germ layers and the body axes. The Spemann–Mangold organizer secretes Chordin, Noggin and related factors that antagonize BMP, inducing dorsal mesoderm and neural tissue.

4. 神经胚（Neurula，NF 13–21）4. Neurula (NF 13–21)

卵黄栓收缩、胚孔封闭后，脊索结构形成。背侧外胚层增厚成神经板，神经板两侧边缘上卷形成神经褶，最终融合形成神经管与神经嵴细胞，分别发育为中枢神经系统和迁移性颅面及周围神经组织。After yolk plug retraction and blastopore closure, the notochord forms. The dorsal ectoderm thickens into a neural plate; its lateral edges elevate into neural folds that fuse to form the neural tube and neural crest cells, precursors of the CNS and migratory craniofacial/peripheral neural tissues.

5. 尾芽期与孵化（NF 22–35）5. Tailbud & hatching (NF 22–35)

体轴形成涉及多个分子调控系统：背侧 Nieuwkoop 中心通过 Wnt/β-Catenin 信号激活脊背基因；各类组织者分泌因子精细调节前后轴与左右不对称。器官原基相继形成，胚胎孵化后进入自由游动的蝌蚪阶段（NF 35 起），开始摄食直至变态为幼蛙。Axis formation involves multiple regulatory systems: the dorsal Nieuwkoop center activates dorsal genes via Wnt/β-catenin; organizer-secreted factors precisely pattern the anterior–posterior and left–right axes. Organ primordia form sequentially; the embryo hatches and begins free-swimming tadpole life (NF 35+), feeding until metamorphosis.

NF 分期简表NF stage summary

NF 期NF Stage阶段名称Stage主要特征Key feature温度 20℃ 时约需时间Approx. time at 20 ℃
1–3受精 / 卵裂初期Fertilization / early cleavage合子 → 8 细胞Zygote → 8-cell0–3 h
4–9囊胚Blastula囊胚腔、MBTBlastocoel, MBT3–8 h
10–12原肠胚Gastrula三胚层建立Three germ layers8–12 h
13–21神经胚Neurula神经管、脊索Neural tube, notochord12–20 h
22–35尾芽期Tailbud体节、器官原基Somites, organ primordia20–48 h
35–46自由游动蝌蚪Free-swimming tadpole开口摄食、鳃、心跳Feeding, gills, heartbeat2–14 d
47–66变态期Metamorphosis四肢、尾部吸收Limb growth, tail resorption数月

我们按 NF 分期提供不同发育时期的蝌蚪与胚胎材料，并可开展早期胚胎单细胞提取与发育毒性实验。We supply staged tadpoles/embryos by NF stage, and offer single-cell isolation and developmental toxicity testing.

各发育期蝌蚪Staged tadpoles 单细胞提取服务Single-cell service

参考文献References

  1. Nieuwkoop PD & Faber J (1994) Normal Table of Xenopus laevis (Daudin), 2nd edn. Garland Publishing, New York.
  2. Harland RM & Gerhart J (1997) Formation and function of Spemann's organizer. Annu Rev Cell Dev Biol 13:611–667.
  3. Heasman J (2006) Patterning the early Xenopus embryo. Development 133:1205–1217.
  4. Sive HL, Grainger RM & Harland RM (2000) Early Development of Xenopus laevis: A Laboratory Manual. Cold Spring Harbor Laboratory Press.