||Fig. 2. Spatio-temporal expression patterns of XBtg2.
(A) Expression of XBtg2 at various stages as detected by RTPCR.
XBtg2 transcripts were present maternally and increased
markedly after the neurula stage (stage 13). (B–I) Whole-mount
in situ hybridization analysis of XBtg2 expression. Lateral (B, E–
F) and dorsal (C, D) view of whole embryos at indicated stages.
(H,I) Transverse sections at the sites indicated by the black
lines in (G). XBtg2 was slightly expressed in the animal
hemisphere of the embryo at stage 10.5 (B). The black
arrowhead indicates dorsal blastopore lip. From stage 12.5,
XBtg2 was expressed strongly in the presomitic mesoderm (C).
At stage 15, XBtg2 expression was detected in the anterior
neural ectoderm (D). At tailbud stages, XBtg2 was expressed in
somite, neural tube, notochord, eyes, midbrain and pronephric
anlagen (E–I). The expression patterns in dorsal structures
showed a dynamic change along the anterior-posterior axis (H,
I); no, notochord; s, presomitic mesoderm; ne, neuraltube. (J) In
situ hybridization analysis of XBtg2 expression on sectioned
embryos. XBtg2 was expressed in the trunk-tail part of
notochord, which vanished subsequent to vacuolation.