Hoxb4 expression patterns during early chick development.
(A-G) Whole-mount RNA in situ hybridization (ISH) using a
Hoxb4 probe. Hamburger and Hamilton (HH) stages are indicated. Black
arrows mark Hensen's node. Red arrows in B-D point to gastrulating cells
expressing Hoxb4. Red lines mark the sixth somite axial level. (A-F)
Ventral view; (G) dorsal view. (H-K) Cross-sections at the level of H-K
in C,F. Dashed circles mark the IM (J,K). (L) Scheme of the expression
patterns of several Hox genes in the IM of a chick embryo. Bars with a blue
margin represent Hox genes that have an anterior boundary at the sixth somite
level. NE, neuroepithelium; m, mesoderm; NT, neural tube; s, somite; LPM,
lateral plate mesoderm. Scale bars: 100 μm.