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Fig. 5. Spatial expression of integrin a 3 mRNA. Whole-mount in situ hybridiztion was performed on albino Xenopus embryos using digoxigenin-labelled a3 antisense (A-K) and sense (L) transcripts. Hybridization signal visualized as alkaline phosphatase chromogenic
reaction product. Anterior end of embryos is oriented to the right in D-K. (A) Gastrula stage 10.5, vegetal pole view; staining of individual cells in dorsal lip region (arrow). (B) Stage 10.5, side view of dorsal involuting mesoderm (arrow). Arrowheads in B and D indicate faint background staining of outer ectodermal layer also observed with gastrula sense controls (L). Blastocoel roof in B is partially collapsed (arrowhead). (C) Dorsal and (D) side view of stage 12 embryo. Note intense staining of the presumptive notochord (arrows). (E) Dorsal and (F) side view of stage 20 embryo. Expression of a 3 observed along entire length of notochord. Anterior progression of staining extends to the prechordal plate (F). (G) Stage 24, side view. Expression of a3 mRNA in the notochord (arrow) is decreased in the anterior portion. (H) Stage 28 and (I) stage 31 embryos, side views. Staining limited to caudal portion of notochord in the developing tail bud (I). Increased staining detected in the head with pronounced expression at the level of the forebrain (arrowheads). (J) Detail of a stage 31 tail bud. Note intense staining at the caudal tip of the notochord (arrow). (K) Stage 39, optical section of anterior end of embryo visualized by differential interference contrast microscopy. Arrowheads indicate borders of a3 mRNA expression in the prosencephalon. (L) Representative tail bud, neurula and gastrula hybridized with a3 sense transcript. Note faint background staining in ectoderm of gastrula and head of tail bud-stage embryo. Scale bar in A, same as in C,D,J,K, equals 100 fliD. Scale bar in B, same as in E-H, equals 200 fliD. Scale bars in I and L equal400 fliD. Y, yolk plug in A-D |
