File:Stages of primordial germ cell migration.jpg

Stages of primordial germ cell migration

a Lateral views (top panels) and transverse sections (bottom panels) showing primordial germ cell (PGC) migration in Drosophila melanogaster. After specification, PGCs are carried into the embryo by the midgut primordium. PGCs polarize and migrate through the midgut epithelium at stages 9−10 (~4.5 hours after egg laying (~4.5 hAEL); step 1). PGCs reorient on the midgut towards the mesoderm at stage 10 (~5 h 10 m AEL; step 2). PGCs migrate bilaterally towards the somatic gonadal precursors (SGPs) at stage 11 (~7 hAEL; step 3). PGCs associate with the SGPs and coalesce to form the embryonic gonad (step 4).

b Following specification at four random locations, PGCs in zebrafish migrate dorsally (step 1; animal pole view — the animal pole refers to the portion of the blastula embryo that differentiates into mesoderm and ectoderm). At gastrulation, 4.5 hours post-fertilization (4.5 hpf), PGCs follow the expression of stromal-derived factor 1a (SDF1A) and at 10.5 hpf somites 1–3 act as intermediate targets (step 2; lateral view, left side). PGCs migrate towards the final target tissue at somites 8–10 at 13 hpf (step 3; frontal view). At 24 hpf, PGCs coalesce with the somatic cells of the gonad (step 4; lateral view, left side).

c PGCs in mice, specified in the proximal epiblast, migrate from the primitive streak to the endoderm (future hindgut) at embryonic day 7.5 (E7.5; step 1). A close-up is shown in the bottom panel. At E8, PGCs migrate along the endoderm (step 2). At E9.5, PGCs migrate bilaterally towards the dorsal body wall (step 3). At E10.5, PGCs reach the genital ridges to form the embryonic gonad (step 4). Lateral views (top panels) and transverse sections (bottom panels) are shown.

Original File Name: Figure 1 Nrm2815-f1.jpg

Reference

<pubmed> 20027186</pubmed>| Nature Reviews Molecular Cell Biology

Reprinted by permission from Macmillan Publishers Ltd: Nature Reviews Molecular Cell Biology "Mechanisms guiding primordial germ cell migration: strategies from different organisms", copyright (2010)