| |
Figure 1.
FN Matrix Is Required for Morphogenesis, but Not for Mesodermal Patterning in Whole Embryos
(A–C) (A) FN matrix assembly, as detected by immunofluorescence, is extensive in stage 12 embryos injected with control mAb 4H2. (B and C) Patterning of mesodermal ([B], Xnot; [C], Xbra) tissues is unaffected by mAb 4H2 injection, as detected by in situ hybridization.
(D–F) (D) Embryos injected with the FN function-blocking mAb 4B12 do not assemble an FN matrix, and the domains of expression of (E) Xnot and (F) Xbra are shorter and wider than in control embryos.
(G–I) (G) En face views of control cells along the inner surface of the blastocoel roof expressing the HA construct (green) support FN matrix assembly (red). (H and I) Patterning of mesodermal ([H], Xnot; [I], Xbra) tissues is normal in embryos expressing HA.
(J–L) (J) Embryos expressing the HAβ1 dominant-negative integrin construct (green) do not assemble an FN matrix (red). (K and L) Patterning of mesodermal ([K], Xnot; [L], Xbra) tissues is unaffected by HAβ1. However, the domains of expression of these marker genes are shorter and wider than in HA-expressing embryos ([H], Xnot; [I], Xbra).
The embryos in (G) and (J) were injected with HA or HAβ1 in one blastomere at the 2 cell stage. Embryos in (H), (I), (K), and (L) received transcript injections at two sites in each of the dorsal blastomeres at the 4 cell stage. The embryos shown in (H), (I), (K), and (L) are slightly older than those depicted in (B), (C), (E), and (F). Embryos are arranged with the blastopore down; anterior is up. |
